piperidines and Spinal-Cord-Injuries

Topics: Alzheimer Disease; Animals; Asthma; Dermatitis, Atopic; Drug Design; Enzyme Inhibitors; Humans; Intramolecular Oxidoreductases; Leukodystrophy, Globoid Cell; Lipocalins; Muscular Dystrophies; Niacinamide; Piperidines; Pulmonary Disease, Chronic Obstructive; Pyrazoles; Pyrimidines; Rhinitis, Allergic, Perennial; Spinal Cord Injuries; Thiazoles

The central nervous system of adult mammals has been classically considered as structurally rigid, tightly wired, and unable to be repaired. We have shown that there exists a rather considerable degree of intrinsic plasticity due to the neurons themselves, but merely to glial cells and to multipotent stem cells. The spinal cord constitutes a good model on which we could demonstrate, with vascular and traumatic animal paradigms, that an early pharmacologic intervention could reduce significantly the extent of lesions and the subsequent functional deficit. Moreover, we showed that regeneration of severed central axons could occur, provided that the astrocytes' component of the glial scar was modified. Finally, transplants of embryonic neurons were shown to repair the axonal circuitry below a sectioned cord, and to restore reflex functions. All these data point to unprecedented perspectives of efficient therapies in acute and chronic neurological diseases.

Topics: Animals; Axons; Cyclohexanes; Cyclohexenes; Fetal Tissue Transplantation; Male; Mammals; Mice; Mice, Knockout; Models, Animal; Nerve Regeneration; Neuronal Plasticity; Neurons; Neuroprotective Agents; Piperidines; Rats; Spinal Cord Injuries

Chronic pain after spinal cord injury (SCI) may present as hyperalgesia, allodynia, and/or spontaneous pain and is often resistant to conventional pain medications. Identifying more effective interventions to manage SCI pain requires improved understanding of the pathophysiological mechanisms involved. Cell cycle activation (CCA) has been implicated as a key pathophysiological event following SCI. We have shown that early central or systemic administration of a cell cycle inhibitor reduces CCA, prevents glial changes, and limits SCI-induced hyperesthesia. Here, we compared the effects of early vs late treatment with the pan-cyclin-dependent kinase inhibitor flavopiridol on allodynia as well as spontaneous pain. Adult C57BL/6 male mice subjected to moderate SCI were treated with intraperitoneal injections of flavopiridol (1 mg/kg), daily for 7 days beginning either 3 hours or 5 weeks after injury. Mechanical/thermal allodynia was evaluated, as well as spontaneous pain using the mouse grimace scale (MGS). We show that sensitivity to mechanical and thermal stimulation, and locomotor dysfunction were significantly reduced by early flavopiridol treatment compared with vehicle-treated controls. Spinal cord injury caused robust and extended increases of MGS up to 3 weeks after trauma. Early administration of flavopiridol significantly shortened duration of MGS changes. Late flavopiridol intervention significantly limited hyperesthesia at 7 days after treatment, associated with reduced glial changes, but without effect on locomotion. Thus, our data suggest that cell cycle modulation may provide an effective therapeutic strategy to reduce hyperesthesia after SCI, with a prolonged therapeutic window.

Topics: Animals; Calcium-Binding Proteins; Cell Cycle; Cell Cycle Proteins; Cell Movement; Disease Models, Animal; Facial Expression; Flavonoids; Ganglia, Spinal; Gene Expression Regulation; Hyperalgesia; Locomotion; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Nerve Tissue Proteins; Neuralgia; Pain Measurement; Piperidines; Protein Kinase Inhibitors; Spinal Cord Injuries; Statistics, Nonparametric

Single centre, single ascending dose study.. To compare the pharmacokinetics and assess the safety of capromorelin, a compound that has potential to treat constipation following spinal cord injury (SCI), in groups of able-bodied and SCI volunteers.. Local population from Victoria, Australia.. Following initial screening and baseline blood collections, participants received ascending oral doses (20, 50 and then 100 mg at least 1-week apart) of capromorelin after pre-dose blood collection, followed by blood collections over the following 12 h for pharmacokinetic analysis and 1-week and 4-week follow-up blood collections for safety evaluations. Blood pressure and heart rate were monitored.. No serious adverse events were recorded following any dose in either the able-bodied group or the SCI group. There were no abnormal blood pressure or heart rate changes. Minor adverse events resolved quickly without the need for treatment. Pharmacokinetic behaviour was broadly similar between groups, with both exhibiting dose-dependent increases in Cmax and AUC0-∞. The SCI participants showed greater variance in pharmacokinetic parameters and had a slightly delayed Tmax and half-life.. Capromorelin at the doses tested was safe and well tolerated in both SCI and able-bodied participants and also showed similar pharmacokinetics with dose-dependent increases in concentration and drug exposure.

Topics: Administration, Oral; Adult; Area Under Curve; Autonomic Agents; Blood Pressure; Dose-Response Relationship, Drug; Follow-Up Studies; Ghrelin; Half-Life; Humans; Male; Piperidines; Pyrazoles; Spinal Cord Injuries; Victoria

Endothelin-1 (ET-1) contributes to the increased peripheral resistance in heart failure and hypertension. Physical inactivity is associated with cardiovascular disease and characterized by increased vascular tone. In this study, we assess the contribution of ET-1 to the increased vascular tone in the extremely deconditioned legs of spinal cord-injured (SCI) individuals before and after exercise training.. In 8 controls and 8 SCI individuals, bilateral thigh blood flow was measured by plethysmography before and during the administration of an ET(A)/ET(B)-receptor blocker into the femoral artery. In SCI, this procedure was repeated after 6 weeks of electro-stimulated training. In a subset of SCI (n=4), selective ET(A)-receptor blockade was performed to determine the role of the ET(A)-receptors. In controls, dual ET-receptor blockade increased leg blood flow at the infused side (10%, P<0.05), indicating a small contribution of ET-1 to leg vascular tone. In SCI, baseline blood flow was lower compared with controls (P=0.05). In SCI, dual ET-receptor blockade increased blood flow (41%, P<0.001). This vasodilator response was significantly larger in SCI compared with controls (P<0.001). The response to selective ET(A)-receptor blockade was similar to the effect of dual blockade. Electro-stimulated training normalized baseline blood flow in SCI and reduced the response to dual ET-receptor blockade in the infused leg (29%, P=0.04).. ET-1 mediates the increased vascular tone of extremely inactive legs of SCI individuals by increased activation of ET(A)-receptors. Physical training reverses the ET-1-pathway, which normalizes basal leg vascular tone.

Topics: Adult; Antihypertensive Agents; Case-Control Studies; Electric Stimulation Therapy; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Exercise; Female; Femoral Artery; Humans; Male; Middle Aged; Muscle, Skeletal; Muscular Atrophy; Oligopeptides; Peptides, Cyclic; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; Regional Blood Flow; Signal Transduction; Spinal Cord Injuries; Vasodilation

Randomized controlled trial. OBJECTIVE.: To determine the effect of low-dose ketamine on the voltage needed to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia in children undergoing scoliosis surgery.. Motor-evoked potentials (MEPs) are increasingly used to assess the integrity of motor pathways during surgery. Whereas most general anesthetics depress MEP amplitude, the effect of ketamine has been variable, ranging from little or no reduction to an increase in amplitude, suggesting that ketamine may be useful as an agent to facilitate MEP monitoring. We tested the hypothesis that low-dose ketamine would reduce the voltage required to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia.. Thirty-four patients 12 to 16 years of age undergoing posterior instrumentation for correction of idiopathic scoliosis were randomly assigned to receive low-dose ketamine (0.5 mg/kg bolus, followed by 4 microg/kg/min infusion) or an equal volume of saline. Anesthesia was maintained using a mixture of 30% oxygen in air, continuous infusion of propofol at a rate of 100 to 150 microg/kg per min, and continuous infusion of remifentanil. Myogenic motor-evoked responses to transcranial electrical stimulation of the motor cortex were recorded. The minimum voltage required to elicit maximal amplitude of the MEP response was determined. Voltage requirements were compared using the Mann-Whitney U rank sum test. P < 0.05 was considered statistically significant.. No significant difference was found in the minimal voltage needed to elicit maximum amplitude of the MEP response. Median (range) voltage requirements in the ketamine and control groups were 227 V (range, 160-350 V) and 215 V (range, 150-300 V), respectively.. Addition of low-dose ketamine to propofol/remifentanil anesthesia does not significantly reduce the voltage needed to elicit maximum amplitude of the motor-evoked response to transcranial electrical stimulation.

Topics: Adolescent; Anesthetics, Dissociative; Anesthetics, Intravenous; Child; Dose-Response Relationship, Drug; Drug Synergism; Efferent Pathways; Evoked Potentials, Motor; Female; Humans; Intraoperative Complications; Ketamine; Male; Monitoring, Intraoperative; Piperidines; Predictive Value of Tests; Propofol; Pyramidal Tracts; Remifentanil; Scoliosis; Sensitivity and Specificity; Spinal Cord Injuries; Transcranial Magnetic Stimulation

Wake-up test can be used during posterior spinal fusion (PSF) to ensure that spinal function remains intact. This study aims at assessing the characteristics of the wake-up test during propofol-alfentanil (PA) vs propofol-remifentanil (PR) infusions for PSF surgery.. Sixty patients with scoliosis and candidates for PSF surgery were randomly allocated in either alfentanil (PA) or remifentanil (PR) group. After an i.v. bolus of alfentanil 30 microg kg(-1) in the PA group or remifentanil 1 microg kg(-1) in the PR group, anaesthesia was induced with thiopental and atracurium. During maintenance, opioid infusion consisted of alfentanil 1 microg kg(-1) min(-1) or remifentanil 0.2 microg kg(-1) min(-1), in the PA group and the PR group, respectively. All patients received propofol 50 microg kg(-1) min(-1). Atracurium was given to maintain the required surgical relaxation. At the surgeon's request, all infusions were discontinued. Patients were asked to move their hands and feet. Time from anaesthetic discontinuation to spontaneous ventilation (T(1)), and from then until movement of the hands and feet (T(2)), and its quality were recorded.. The average T(1) and T(2) were significantly shorter in the PR group [3.6 (2.5) and 4.1 (2) min] than the PA group [6.1 (4) and 7.5 (4.5) min]. Quality of wake-up test, however, did not show significant difference between the two groups studied.. Wake-up test can be conducted faster with remifentanil compared with alfentanil infusion during PSF surgery.

Topics: Adolescent; Adult; Alfentanil; Analgesics, Opioid; Anesthetics, Combined; Anesthetics, Intravenous; Auditory Perception; Female; Humans; Intraoperative Care; Male; Movement; Piperidines; Propofol; Reaction Time; Remifentanil; Scoliosis; Spinal Cord Injuries; Spinal Fusion

To compare spectral analysis of the electrocardiogram (ECG) with mean arterial pressure (MAP) and heart rate (HR) monitoring in the detection of autonomic hyperreflexia (AHR) induced by sacral root stimulation.. Ten spinal cord injured patients scheduled for implantation of a sacral root stimulator for bladder retention were included. Under target controlled anesthesia with propofol 4 micro g*mL(-1) and remifentanil 4 ng*mL(-1), the patients were placed in the knee chest position. The sacral roots were exposed by laminectomy (L2-S1) and their function assessed by electrostimulation under urodynamic and cardiovascular monitoring. Online power spectrum densities were calculated from the ECG R-R interval by the MemCalc(TM) software using the maximum entropy method. Low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) spectra were associated with sympathetic and parasympathetic activities respectively. The most extreme value of each variable was noted before and during each stimulation. A difference ( triangle up ) of more than 10% signified AHR. The comparison ( triangle up LF vs triangle up MAP and triangle up HF vs triangle up HR) was done by a concordance test with a kappa coefficient (k): -1 = total discordance to 1 = total concordance.. AHR was detected in six patients as an increase in LF and MAP (n = 4); an increase in LF, HF, MAP with a decrease in HR (n = 2). The detection delay was 5.3 +/- 1 sec (LF, HF) and 10.4 +/- 1.2 sec (MAP and HR). Concordance was 85% (LF vs MAP: k = 0.7) and 90% (HF vs HR: k = 0.8).. AHR induced by sacral root stimulation is detected by spectral analysis of the ECG earlier than MAP and HR. Other studies are needed to confirm these results.

Topics: Adolescent; Adult; Anesthetics, Intravenous; Autonomic Dysreflexia; Blood Pressure; Electric Stimulation; Electrocardiography; Female; Heart Rate; Humans; Laminectomy; Male; Middle Aged; Monitoring, Intraoperative; Piperidines; Propofol; Reflex, Abnormal; Remifentanil; Spinal Cord Injuries; Spinal Nerve Roots; Urinary Incontinence; Urodynamics

The pathophysiological consequences of spinal cord injury (SCI) on function of the colon are complex and poorly understood. Regardless of the mechanism, many patients with SCI have deficient bowel control, which is frustrating and difficult to treat. We designed a study to assess whether a new prokinetic medication, cisapride, might be useful in this setting.. Total and segmental colonic transit time were measured using the radiopaque marker technique in nine subjects with spinal cord injury and seven control subjects after the double-blind administration of cisapride (10 mg q.i.d.) or placebo.. In five quadriplegic subjects with prolonged colonic transit time, administration of cisapride was found to reduce left-sided colonic transit time from 24.2 to 13.8 h. In three of these five subjects, cisapride administration resulted in subjective improvement. No effect of cisapride on right-sided, rectosigmoid, or total colonic transit time was observed.. The data suggest that cisapride might be a useful adjunctive measure in treating a subset of SCI patients with colonic inertia, but a larger study is needed before this can be routinely recommended.

Topics: Adult; Aged; Cisapride; Colon; Constipation; Double-Blind Method; Gastrointestinal Transit; Humans; Male; Middle Aged; Piperidines; Spinal Cord Injuries; Sympathomimetics; Treatment Outcome

A group of 21 complete spinal cord injury patients, beyond the phase of spinal shock, were given a treatment of cisapride at random, 10 mg four times a day for 4 weeks. Cystometry was performed first before the start and during the following 4 weeks. No statistically significant difference could be found in the urodynamic parameters between the two groups at the first cystometry. No statistically significant change of the urodynamic parameters could be demonstrated with the treatment, although a non-statistically significant bladder stimulating effect was present in a majority of the patients in the cisapride group.

Topics: Adolescent; Adult; Cisapride; Double-Blind Method; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Parasympathomimetics; Piperidines; Spinal Cord Injuries; Treatment Outcome; Urinary Bladder, Neurogenic; Urodynamics

Heartburn, bloating, and abdominal discomfort are common problems in patients with spinal cord injury but, despite its clinical significance, little is known about the gastrointestinal effects of spinal transections. To address the potential gastrointestinal pathophysiology of spinal cord injury, we measured mouth-to-cecum transit time (MCTT) in seven subjects with paraplegia and seven with quadriplegia. Gastric emptying was studied in six subjects with quadriplegia. MCTT was significantly prolonged in patients with quadriplegia, an abnormality corrected by the administration of cisapride. Patients with paraplegia, in contrast to those with quadriplegia, have normal mouth-to-cecum transit time. In addition, patients with quadriplegia had neither a prolonged gastric emptying time nor a change in gastric emptying time, with cisapride. Changes in gastrointestinal transit after spinal cord injury and the improvement of mouth-to-cecum transit time in subjects with quadriplegia, but not in those with paraplegia, may be explained by an imbalance between parasympathetic and sympathetic outflows to the gastrointestinal tract in this group of subjects.

Topics: Adult; Aged; Cisapride; Double-Blind Method; Gastric Emptying; Gastrointestinal Transit; Humans; Male; Middle Aged; Paraplegia; Piperidines; Quadriplegia; Serotonin Antagonists; Spinal Cord Injuries

Microglia/astrocyte and B cell neuroimmune responses are major contributors to the neurological deficits after traumatic spinal cord injury (SCI). Bruton tyrosine kinase (BTK) activation mechanistically links these neuroimmune mechanisms. Our objective is to use Ibrutinib, an FDA-approved BTK inhibitor, to inhibit the neuroimmune cascade thereby improving locomotor recovery after SCI. Rat models of contusive SCI, Western blot, immunofluorescence staining imaging, flow cytometry analysis, histological staining, and behavioral assessment were used to evaluate BTK activity, neuroimmune cascades, and functional outcomes. Both BTK expression and phosphorylation were increased at the lesion site at 2, 7, 14, and 28 days after SCI. Ibrutinib treatment (6 mg/kg/day, IP, starting 3 h post-injury for 7 or 14 days) reduced BTK activation and total BTK levels, attenuated the injury-induced elevations in Iba1, GFAP, CD138, and IgG at 7 or 14 days post-injury without reduction in CD45RA B cells, improved locomotor function (BBB scores), and resulted in a significant reduction in lesion volume and significant improvement in tissue-sparing 11 weeks post-injury. These results indicate that Ibrutinib exhibits neuroprotective effects by blocking excessive neuroimmune responses through BTK-mediated microglia/astroglial activation and B cell/antibody response in rat models of SCI. These data identify BTK as a potential therapeutic target for SCI.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Animals; Antibody Formation; Astrocytes; B-Lymphocytes; Body Weight; Calcium-Binding Proteins; Glial Fibrillary Acidic Protein; Immunoglobulin G; Macrophage Activation; Macrophages; Microfilament Proteins; Microglia; Motor Activity; Neuroimmunomodulation; Phosphorylation; Piperidines; Plasma Cells; Rats; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Spleen; Syndecan-1; Treatment Outcome; Up-Regulation

Spinal cord injury (SCI) above the lumbosacral level results in lower urinary tract dysfunction, including (1) detrusor hyperreflexia, wherein bladder compliance is low, and (2) a lack of external urethral sphincter (EUS) control, leading to detrusor-sphincter dyssynergia (DSD) with poor voiding efficiency. Experimental studies in animals have shown a dense innervation of serotonergic (5-HT) fibers and multiple 5-HT receptors in the spinal reflex circuits that control voiding function. Here, we investigated the efficacy of NLX-112 (a.k.a. befiradol or F13640), in regulating lower urinary tract function after T8 contusive SCI in rats. NLX-112 is a very potent, highly-selective, and fully efficacious 5-HT

Topics: Animals; Dose-Response Relationship, Drug; Electromyography; Female; Piperidines; Pyridines; Rats; Rats, Sprague-Dawley; Receptor, Serotonin, 5-HT1A; Serotonin 5-HT1 Receptor Agonists; Spinal Cord Injuries; Urethra; Urinary Bladder Diseases; Urinary Bladder, Neurogenic; Urinary Bladder, Overactive; Urinary Tract; Urination; Urodynamics

The present work proposed a novel therapeutic platform with both neuroprotective and neuroregenerative potential to be used in the treatment of spinal cord injury (SCI). A dual-functioning scaffold for the delivery of the neuroprotective S1R agonist, RC-33, to be locally implanted at the site of SCI, was developed. RC-33-loaded fibers, containing alginate (ALG) and a mixture of two different grades of poly(ethylene oxide) (PEO), were prepared by electrospinning. After ionotropic cross-linking, fibers were incorporated in chitosan (CS) films to obtain a drug delivery system more flexible, easier to handle, and characterized by a controlled degradation rate. Dialysis equilibrium studies demonstrated that ALG was able to form an interaction product with the cationic RC-33 and to control RC-33 release in the physiological medium. Fibers loaded with RC-33 at the concentration corresponding to 10% of ALG maximum binding capacity were incorporated in films based on CS at two different molecular weights-low (CSL) and medium (CSM)-solubilized in acetic (AA) or glutamic (GA) acid. CSL- based scaffolds were subjected to a degradation test in order to investigate if the different CSL salification could affect the film behavior when in contact with media that mimic SCI environment. CSL AA exhibited a slower biodegradation and a good compatibility towards human neuroblastoma cell line.

Topics: Alginates; Biphenyl Compounds; Cell Line, Tumor; Chitosan; Drug Carriers; Drug Delivery Systems; Humans; Molecular Weight; Nanofibers; Neuroblastoma; Neuroprotective Agents; Piperidines; Polyethylene Glycols; Receptors, sigma; Sigma-1 Receptor; Spinal Cord Injuries

Myelin-laden macrophages (mye-MΦ), resulting primarily from internalization of myelin debris by infiltrating bone marrow-derived macrophages in spinal cord injury (SCI), trigger inflammatory responses that largely contribute to secondary injury. Adiponectin, which is secreted from adipose tissue, is an important hormone that modulates macrophage inflammation. In the present study, we examined the role of adiponectin on macrophage-mediated neuroinflammation after SCI. We found that in vitro activation of adiponectin receptors (AdipoRs) by their agonist AdipoRon suppressed myelin lipid accumulation in mye-MΦ through APPL1/PPARγ/LXRα/ABCA1-mediated lipid efflux, subsequently inhibiting inflammation and restoring normal function to mye-MΦ. In vivo data further confirmed that intravenous administration of AdipoRon after SCI dampened recruitment of macrophages and reduced myelin lipid accumulation. Accordingly, AdipoRon treatment ameliorated post-SCI tissue damage and astrogliosis, resulting in improved motor function. Although there was no significant pathological exacerbation in adiponectin-null mice subjected to SCI, our work reveals a functional link between adiponectin and hematogenous macrophages in the context of SCI, suggesting that activation of adiponectin signaling is a promising therapeutic approach to mitigate mye-MΦ-mediated neuroinflammation in neurological disorders involving demyelination.

Topics: Adiponectin; Animals; Inflammation; Lipids; Macrophage Activation; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Myelin Sheath; Piperidines; Receptors, Adiponectin; Signal Transduction; Spinal Cord Injuries

To characterize the effects of acute spinal cord injury (SCI) on mitochondrial morphology and function in bladder urothelium and to test the therapeutic efficacy of early treatment with the mitochondrially targeted antioxidant, MitoTempo.. We used a mouse model of acute SCI by spinal cord transection between the T8-T9 vertebrae with or without MitoTempo delivery at the time of injury followed by tissue processing at 3 days after SCI. Control, SCI, and SCI-MitoTempo-treated mice were compared in all experimental conditions. Assessments included analysis of markers of mitochondrial health including accumulation of reactive oxygen species (ROS), morphological changes in the ultrastructure of mitochondria by transmission electron microscopy, and Western blot analysis to quantify protein levels of markers for autophagy and altered mitochondrial dynamics.. SCI resulted in an increase in oxidative stress markers and ROS production, confirming mitochondrial dysfunction. Mitochondria from SCI mice developed large electron-dense inclusions and these aberrant mitochondria accumulated throughout the cytoplasm suggesting an inability to clear dysfunctional mitochondria by mitophagy. SCI mice also exhibited elevated levels of dynamin-related protein 1 (DRP1), consistent with a disruption of mitochondrial dynamics. Remarkably, treatment with MitoTempo reversed many of the SCI-induced abnormalities that we observed.. Acute SCI negatively and severely affects mitochondrial health of bladder urothelium. Early treatment of SCI with MitoTempo may be a viable therapeutic agent to mitigate these deleterious effects.

Topics: Acute Disease; Animals; Antioxidants; Apoptosis; Autophagy; Dynamins; Female; Mice; Mice, Inbred C57BL; Mitochondria; Mitochondrial Diseases; Organophosphorus Compounds; Oxidative Stress; Piperidines; Reactive Oxygen Species; Spinal Cord Injuries; Urothelium

Isopsoralen is a type of furocoumarin that exhibits estrogen-like activities. The aim of this study was to determine the estrogen-like neuroprotection of isopsoralen in an animal model of spinal cord injury (SCI). Results indicated that isopsoralen (intraperitoneal injection of 5 and 10 mg/kg per day for two weeks) significantly enhanced the hindlimb locomotor functions of mice with SCI, as revealed in the BMS score and angle of inclined plane tests. Morphological data showed that isopsoralen significantly attenuated the injury of the gray matter of spinal cord and induced the up-regulation of ERα levels. The neuroprotective effects of isopsolaren were blocked by the ERα antagonist MPP (0.3 mg/kg), but not by the ERβ receptor antagonist PHTPP (0.3 mg/kg). Isopsolaren treatment increased phosphorylated PI3K and AKT (P-PI3K and P-AKT) in the spinal cord of SCI mice and showed a significant anti-apoptotic activity. These results suggest that isopsoralen performs estrogen-like neuroprotection against SCI-induced apoptosis by activating ERα and regulating the PI3K/AKT pathway.

Topics: Animals; Estrogen Receptor alpha; Furocoumarins; Hormone Antagonists; Male; Mice; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphorylation; Piperidines; Pyrazoles; Signal Transduction; Spinal Cord; Spinal Cord Injuries; Up-Regulation

Endocannabinoids acting on cannabinoid-1 receptors (CB1Rs) are proposed to protect brain and spinal neurons from excitotoxic damage. The ability to recover from spinal cord injury (SCI), in which excitotoxicity is a major player, is usually investigated at late times after modulation of CB1Rs whose role in the early phases of SCI remains unclear. Using the rat spinal cord in vitro as a model for studying SCI initial pathophysiology, we investigated if agonists or antagonists of CB1Rs might affect SCI induced by the excitotoxic agent kainate (KA) within 24h from a transient (1h) application of this glutamate agonist. The CB1 agonist anandamide (AEA or pharmacological block of its degradation) did not limit excitotoxic depolarization of spinal networks: cyclic adenosine monophosphate (cAMP) assay demonstrated that CB1Rs remained functional 24h later and similarly expressed among dead or survived cells. Locomotor-like network activity recorded from ventral roots could not recover with such treatments and was associated with persistent depression of synaptic transmission. Motoneurons, that are particularly vulnerable to KA, were not protected by AEA. Application of 2-arachidonoylglycerol also did not attenuate the electrophysiological and histological damage. The intensification of damage by the CB1 antagonist AM251 suggested that endocannabinoids were operative after excitotoxic stimulation, yet insufficient to contrast it efficiently. The present data indicate that the early phases of excitotoxic SCI could not be arrested by pharmacologically exploiting the endocannabinoid system, consistent with the notion that AEA and its derivatives are more useful to treat late SCI phases.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Disease Models, Animal; Endocannabinoids; Glycerides; Kainic Acid; Locomotion; Motor Neurons; Neural Pathways; Neuroprotection; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats, Wistar; Receptor, Cannabinoid, CB1; Spinal Cord; Spinal Cord Injuries; Tissue Culture Techniques

Spinal cord injury (SCI) is a serious condition of the central nervous system and it affects the quality of life and even hampers the day-to-day activity of the patient. In the current study, we investigated the efficacy of intrathecal administration of flavopiridol in an experimental animal model of SCI. The study also aimed at exploring the physiological effects of flavopiridol on neurons, astrocytes and cell cycle regulatory proteins.. In vitro scratch wound experiments were performed on female Sprague-Dawley rats (n=23). A complete hemisection to the right of T10 was made, and flavopiridol solution (200 mM, 0.8 nmol flavopiridol/animal) was delivered topically to the lesion site. Cell viability assay, in vitro scratch injury assay, cell cycle analysis using flow cytometry and behavioural assessments were performed.. The local delivery of flavopiridol reduced cavity formation and improved regeneration of neurons with improvement in physiological performance. Flavopiridol also inhibited the migration and proliferation of astrocytes, and at the same time, promoted the survival of neurons.. Intrathecal administration of flavopiridol can be a promising treatment strategy in patients with SCI and it needs to be validated in patient setting.

Topics: Administration, Topical; Animals; Astrocytes; Cell Movement; Cell Proliferation; Cell Survival; Disease Models, Animal; Female; Flavonoids; Nerve Regeneration; Neurons; Piperidines; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries

After spinal cord injury (SCI), the disruption of blood-spinal cord barrier by activation of the endothelin (ET) system is a critical event leading to leukocyte infiltration, inflammatory response and oxidative stress, contributing to neurological disability. In the present study, we showed that blockade of ET receptor A (ETAR) and/or ET receptor B (ETBR) prevented early inflammatory responses directly via the inhibition of neutrophil and monocyte diapedesis and inflammatory mediator production following traumatic SCI in mice. Long-term neurological improvement, based on a series of tests of locomotor performance, occurred only in the spinal cord‑injured mice following blockade of ETAR and ETBR. We also examined the post‑traumatic changes of the micro-environment within the injured spinal cord of mice following blockade of ET receptors. Oxidative stress reflects an imbalance between malondialdehyde and superoxide dismutase in spinal cord‑injured mice treated with vehicle, whereas blockade of ETAR and ETBR reversed the oxidation state imbalance. In addition, hemeoxygenase-1, a protective protease involved in early SCI, was increased in spinal cord‑injured mice following the blockade of ETAR and ETBR, or only ETBR. Matrix metalloproteinase-9, a tissue-destructive protease involved in early damage, was decreased in the injured spinal cord of mice following blockade of ETAR, ETBR or a combination thereof. The findings of the present study therefore suggested an association between ETAR and ETBR in regulating early pathogenesis of SCI and determining the outcomes of long‑term neurological recovery.

Topics: Animals; Cell Movement; Endothelin Receptor Antagonists; Female; Gene Expression Regulation; Heme Oxygenase-1; Inflammation; Malondialdehyde; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Monocytes; Motor Activity; Neutrophils; Oligopeptides; Peptides, Cyclic; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; Recovery of Function; Signal Transduction; Spinal Cord; Spinal Cord Injuries; Superoxide Dismutase

Amelioration of neuropathic spinal cord injury (SCI) pain is a clinical challenge. Increasing the endocannabinoid anandamide and other fatty acid amides (FAA) by blocking fatty acid amide hydrolase (FAAH) has been shown to be antinociceptive in a number of animal models of chronic pain. However, an antinociceptive effect of blocking FAAH has yet to be demonstrated in a rat model of neuropathic SCI pain. Four weeks following a SCI, rats developed significantly decreased hind paw withdrawal thresholds, indicative of below-level cutaneous hypersensitivity. A group of SCI rats were systemically treated (i.p.) with either the selective FAAH inhibitor URB597 or vehicle twice daily for seven days. A separate group of SCI rats received a single dose (p.o.) of either the selective FAAH inhibitor PF-3845 or vehicle. Following behavioral testing, levels of the FAA N-arachidonoylethanolamide, N-oleoyl ethanolamide and N-palmitoyl ethanolamide were quantified in brain and spinal cord from SCI rats. Four weeks following SCI, FAA levels were markedly reduced in spinal cord tissue. Although systemic treatment with URB597 significantly increased CNS FAA levels, no antinociceptive effect was observed. A significant elevation of CNS FAA levels was also observed following oral PF-3845 treatment, but only a modest antinociceptive effect was observed. Increasing CNS FAA levels alone does not lead to robust amelioration of below-level neuropathic SCI pain. Perhaps utilizing FAAH inhibition in conjunction with other analgesic mechanisms could be an effective analgesic therapy.

Topics: Amidohydrolases; Analgesics; Animals; Arachidonic Acids; Benzamides; Benzoxazines; Brain; Carbamates; Endocannabinoids; Enzyme Inhibitors; Hindlimb; Male; Morpholines; Naphthalenes; Neuralgia; Pain Measurement; Pain Threshold; Piperidines; Polyunsaturated Alkamides; Pyridines; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Treatment Outcome

The cell-cycle inhibitor flavopiridol has been shown to improve recovery from spinal cord injury in animal models. However, the systemic dose of flavopiridol has side-effects and the mechanism of action is not clear. This study aimed to develop a strategy for the local delivery of flavopiridol and investigate its mechanisms of action. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were used for the sustained delivery of flavopiridol. The spinal cord was right-hemisectioned and NPs were delivered into the injury site. Transparent spinal cord technology was used for the three-dimensional observation of anterograde tracing. The results showed that flavopiridol NPs had a sustained release of up to 3 days in vitro. Flavopiridol NPs significantly decreased inflammatory factor synthesis by astrocytes, including TNF-α, IL-1β, and IL-6, while the IL-10 expression was elevated. In vivo study demonstrated that flavopiridol NPs decreased cell-cycle activation, inflammatory expression and glial scarring, and facilitated neuronal survival and regeneration. The cavitation volume was decreased by ~90%. Administration of flavopiridol NPs also improved the motor recovery of injured animals. These findings demonstrated that local delivery of flavopiridol in PLGA NPs improves recovery from spinal cord injury by inhibiting astrocyte growth and inflammatory factor synthesis.

Topics: Animals; Astrocytes; Behavior, Animal; Cell Cycle Proteins; Cell Proliferation; Cells, Cultured; Drug Delivery Systems; Female; Flavonoids; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Inflammation; Inflammation Mediators; Lactic Acid; Microtubule-Associated Proteins; Nanoparticles; Neurons; Piperidines; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries; Wound Healing

Injury to the CNS leads to formation of scar tissue, which is important in sealing the lesion and inhibiting axon regeneration. The fibrotic scar that comprises a dense extracellular matrix is thought to originate from meningeal cells surrounding the CNS. However, using transgenic mice, we demonstrate that perivascular collagen1α1 cells are the main source of the cellular composition of the fibrotic scar after contusive spinal cord injury in which the dura remains intact. Using genetic lineage tracing, light sheet fluorescent microscopy, and antigenic profiling, we identify collagen1α1 cells as perivascular fibroblasts that are distinct from pericytes. Our results identify collagen1α1 cells as a novel source of the fibrotic scar after spinal cord injury and shift the focus from the meninges to the vasculature during scar formation.

Topics: Analysis of Variance; Animals; Antigens; Blood Vessels; CD13 Antigens; Cell Count; Cicatrix; Collagen Type I; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Disease Progression; Female; Fibroblasts; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Green Fluorescent Proteins; Lectins; Leukocyte Common Antigens; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pericytes; Piperidines; Proteoglycans; Receptor, Platelet-Derived Growth Factor beta; Spinal Cord Injuries; Time Factors; Uracil

N-Methyl-d-aspartate (NMDA) receptors are thought to play an important role in the processes of central sensitization and pathogenesis of neuropathic pain, particularly after spinal cord injury (SCI). NMDA antagonists effectively reduce neuropathic pain, but serious side effects prevent their use as therapeutic drugs. NMDA NR2B antagonists have been reported to effectively reduce inflammatory and neuropathic pain. In this study, we investigated the effects of NR2B antagonists on neuropathic pain and the expression of NR2B in the spinal cord in 2 SCI models. SCI was induced at T12 by a New York University impactor (contusion) or by sectioning of the lateral half of the spinal cord (hemisection). Ifenprodil (100, 200, 500, 1000nmol) and Ro25-6981 (20, 50, 100, 200nmol) were intrathecally injected and behavioral tests were conducted. Ifenprodil increased the paw withdrawal threshold in both models but also produced mild motor depression at higher doses. Ro25-6981 increased the mechanical nociceptive threshold in a dose-dependent manner without motor depression. NR2B expression was significantly increased on both sides at the spinal segments of L1-2 and L4-5 in the hemisection model but did not change in the contusion model. Increased expression of NR2B in the hemisection model was reduced by intrathecal ifenprodil. These results suggest that intrathecal NMDA NR2B antagonist increased the mechanical nociceptive threshold after SCI without motor depression. A selective subtype of NMDA receptor, such as NR2B, may be a more selective target for pain control because NMDA receptors play a crucial role in the development and maintenance of chronic pain.

Topics: Animals; Behavior, Animal; Excitatory Amino Acid Antagonists; Male; Neuralgia; Pain Measurement; Phenols; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Spinal Cord; Spinal Cord Injuries

Emerging data implicate nicotinamide phosphoribosyl transferase (NAMPT) in the pathogenesis of cancer and inflammation. NAMPT inhibitors have proven beneficial in inflammatory animal models of arthritis and endotoxic shock as well as in autoimmune encephalitis. Given the role of inflammatory responses in spinal cord injury (SCI), the effect of NAMPT inhibitors was examined in this setting.. We investigated the effects of the NAMPT inhibitor FK866 in an experimental compression model of SCI.. Twenty-four hr following induction of SCI, a significant functional deficit accompanied widespread edema, demyelination, neuron loss and a substantial increase in TNF-α, IL-1β, PAR, NAMPT, Bax, MPO activity, NF-κB activation, astrogliosis and microglial activation was observed. Meanwhile, the expression of neurotrophins BDNF, GDNF, NT3 and anti-apoptotic Bcl-2 decreased significantly. Treatment with FK866 (10 mg/kg), the best known and characterized NAMPT inhibitor, at 1 h and 6 h after SCI rescued motor function, preserved perilesional gray and white matter, restored anti-apoptotic and neurotrophic factors, prevented the activation of neutrophils, microglia and astrocytes and inhibited the elevation of NAMPT, PAR, TNF-α, IL-1β, Bax expression and NF-κB activity.We show for the first time that FK866, a specific inhibitor of NAMPT, administered after SCI, is capable of reducing the secondary inflammatory injury and partly reduce permanent damage. We also show that NAMPT protein levels are increased upon SCI in the perilesional area which can be corrected by administration of FK866.. Our findings suggest that the inflammatory component associated to SCI is the primary target of these inhibitors.

Topics: Acrylamides; Alcohol Oxidoreductases; Animals; Cytokines; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; In Situ Nick-End Labeling; Laminectomy; Male; Mice; Movement Disorders; Nerve Growth Factors; Nerve Tissue Proteins; Neutrophil Infiltration; NF-kappa B; Nicotinamide Phosphoribosyltransferase; Peroxidase; Phosphorylation; Piperidines; Silver Staining; Spinal Cord; Spinal Cord Injuries; Time Factors

Traumatic spinal cord injury (SCI) causes tissue loss and associated neurological dysfunction through mechanical damage and secondary biochemical and physiological responses. We have previously described the pathobiological role of cell cycle pathways following rat contusion SCI by examining the effects of early intrathecal cell cycle inhibitor treatment initiation or gene knockout on secondary injury. Here, we delineate changes in cell cycle pathway activation following SCI and examine the effects of delayed (24 h) systemic administration of flavopiridol, an inhibitor of major cyclin-dependent kinases (CDKs), on functional recovery and histopathology in a rat SCI contusion model. Immunoblot analysis demonstrated a marked upregulation of cell cycle-related proteins, including pRb, cyclin D1, CDK4, E2F1 and PCNA, at various time points following SCI, along with downregulation of the endogenous CDK inhibitor p27. Treatment with flavopiridol reduced induction of cell cycle proteins and increased p27 expression in the injured spinal cord. Functional recovery was significantly improved after SCI from day 7 through day 28. Treatment significantly reduced lesion volume and the number of Iba-1(+) microglia in the preserved tissue and increased the myelinated area of spared white matter as well as the number of CC1(+) oligodendrocytes. Furthermore, flavopiridol attenuated expression of Iba-1 and glactin-3, associated with microglial activation and astrocytic reactivity by reduction of GFAP, NG2, and CHL1 expression. Our current study supports the role of cell cycle activation in the pathophysiology of SCI and by using a clinically relevant treatment model, provides further support for the therapeutic potential of cell cycle inhibitors in the treatment of human SCI.

Topics: Animals; Apoptosis; Calcium-Binding Proteins; Cell Cycle; Cell Cycle Proteins; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p27; E2F1 Transcription Factor; Flavonoids; Immunohistochemistry; Locomotion; Male; Microfilament Proteins; Microglia; Neurons; Oligodendroglia; Piperidines; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Time Factors

An inhaled anesthetic concentration required to block autonomic hyperreflexia (AHR) is high enough to cause severe hypotension in patients with high spinal cord injury (SCI). We determined the effects of remifentanil on the sevoflurane requirement to block AHR in SCI.. The study involved 96 patients with chronic, complete SCI scheduled to undergo transurethral litholapaxy during general anesthesia. Anesthesia was induced with thiopental, and sevoflurane concentrations in 50% nitrous oxide were adjusted to maintain a bispectral index of 40 to 50. Whether the patient develops an AHR [an increase of systolic blood pressure (SBP) >20 to 40 mm Hg] was first examined by distending the bladder with glycine solution (the first trial). Patients who developed AHR were then allocated to receive no remifentanil infusion (control, n = 31), a target-controlled plasma concentration of 1 ng/mL (n = 25), or 3 ng/mL remifentanil (n = 24). After baseline hemodynamics had recovered, the target sevoflurane and remifentanil concentrations were maintained for at least 20 minutes and the procedure was resumed (the second trial). Each target sevoflurane concentration was determined by the up-and-down method based on changes (15% increase or more) of SBP in response to the bladder distension. SBP, heart rate, and bispectral index were measured before and during the bladder distension during the trials, and plasma concentrations of catecholamines during the first trial.. Eighty-two (85.4%) of 96 patients developed AHR during the first trial, in which 2 were excluded because of hypotension (mean arterial blood pressure <50 mm Hg) developed during target-controlled drug administration. During the second trial, the end-tidal concentrations of sevoflurane to prevent AHR were reduced to 2.6% (95% confidence interval 2.5% to 2.8%, P < 0.01) and 2.2% (2.1% to 2.4%, P < 0.0001) in the groups receiving 1 and 3 ng/mL remifentanil, respectively, in comparison with 3.1% (2.9% to 3.3%) in the control. When considering minimum anesthetic concentration (MAC) values and the contribution of 50% nitrous oxide (0.48 MAC), the combined MAC values, expressed as multiples of MAC, were 2.27, 1.98, and 1.75 in the control, 1 ng/mL remifentanil, and 3 ng/mL remifentanil groups, respectively.. Target-controlled concentrations of 1 and 3 ng/mL remifentanil would reduce the requirement of sevoflurane combined with 50% nitrous oxide to block AHR by 16% and 29%, respectively, in SCI patients undergoing transurethral litholapaxy.

Topics: Adult; Autonomic Dysreflexia; Drug Therapy, Combination; Female; Humans; Lithotripsy; Male; Methyl Ethers; Middle Aged; Piperidines; Remifentanil; Sevoflurane; Spinal Cord Injuries; Thoracic Vertebrae; Urethra

Prostaglandin D(2) (PGD(2) ) is a potent inflammatory mediator, which is implicated in both the initiation and resolution of inflammation in peripheral non-neural tissues. Its role in the central nervous system has not been fully elucidated. Spinal cord injury (SCI) is associated with an acute inflammatory response, which contributes to secondary tissue damage that worsens functional loss. We show here, with the use of hematopoietic prostaglandin D synthase (HPGDS) deficient mice and a HPGDS selective inhibitor (HQL-79), that PGD(2) plays a detrimental role after SCI. We also show that HPGDS is expressed in macrophages in the injured mouse spinal cord and contributes to the increase in PGD(2) in the contused spinal cord. HPGDS(-/-) mice also show reduced secondary tissue damage and reduced expression of the proinflammatory chemokine CXCL10 as well as an increase in IL-6 and TGFβ-1 expression in the injured spinal cord. This was accompanied by a reduction in the expression of the microglia/macrophage activation marker Mac-2 and an increase in the antioxidant metallothionein III. Importantly, HPGDS deficient mice exhibit significantly better locomotor recovery after spinal cord contusion injury than wild-type (Wt) mice. In addition, systemically administered HPGDS inhibitor (HQL-79) also enhanced locomotor recovery after SCI in Wt mice. These data suggest that PGD(2) generated via HPGDS has detrimental effects after SCI and that blocking the activity of this enzyme can be beneficial.

Topics: Analysis of Variance; Animals; Female; Galectin 3; Immunoenzyme Techniques; Interleukin-6; Intramolecular Oxidoreductases; Isomerases; Macrophages; Metallothionein 3; Mice; Mice, Knockout; Microglia; Nerve Tissue Proteins; Piperidines; Recovery of Function; Reverse Transcriptase Polymerase Chain Reaction; Spinal Cord; Spinal Cord Injuries

Animal proof of principle study.. To determine whether capromorelin, a compound that causes defecation by stimulating ghrelin receptors within the lumbosacral defecation centers, is effective after spinal cord injury (SCI), and whether SCI significantly alters sensitivity to the compound.. University of Melbourne and Austin Hospital, Melbourne, Australia.. Rats were subjected to spinal cord contusion injury or were sham-operated. At 6 weeks after surgery, effects of capromorelin on blood pressure, heart rate and propulsive contractions of the colorectum were investigated.. Capromorelin caused robust propulsive activity in the colorectum soon after its application. The compound was similarly effective in naïve, sham-operated and spinal cord-injured rats. Blood pressure increases caused by capromorelin were not exaggerated after SCI, and there was no evidence of phasic blood pressure increases when the colon was contracted by the compound.. Capromorelin is a therapeutic compound that could potentially be used to relieve constipation by triggering defecation in spinal cord-injured patients.

Topics: Animals; Constipation; Defecation; Disease Models, Animal; Growth Hormone; Male; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptors, Ghrelin; Spinal Cord Injuries

The purpose of this study was to examine the pharmacologic plasticity of cholinergic, non-adrenergic non-cholinergic (NANC), and purinergic contractions in neurogenic bladder strips from spinal cord injured (SCI) rats. Bladder strips were harvested from female rats three to four weeks after T(9)-T(10) spinal cord transection. The strips were electrically stimulated using two experimental protocols to compare the contribution of muscarinic and NANC/purinergic contractions in the presence and the absence of carbachol or muscarine. The endpoints of the study were: (1) percent NANC contraction that was unmasked by the muscarinic antagonist 4-DAMP, and (2) P2X purinergic contraction that was evoked by α,β-methylene ATP. NANC contraction accounted for 78.5% of the neurally evoked contraction in SCI bladders. When SCI bladder strips were treated with carbachol (10 μM) prior to 4-DAMP (500 nM), the percent NANC contraction decreased dramatically to only 13.1% of the neurally evoked contraction (P=0.041). This was accompanied by a substantial decrease in α,β-methylene ATP evoked P2X contraction, and desensitization of purinergic receptors (the ratio of subsequent over initial P2X contraction decreased from 97.2% to 42.1%, P=0.0017). Sequential activation of the cholinergic receptors with carbachol (or with muscarine in neurally intact bladders) and unmasking of the NANC response with 4-DAMP switched the neurally evoked bladder contraction from predominantly NANC to predominantly cholinergic. We conclude that activation of muscarinic receptors (with carbachol or muscarine) blocks NANC and purinergic contractions in neurally intact or in SCI rat bladders. The carbachol-induced inhibition of the NANC contraction is expressed more in SCI bladders compared to neurally intact bladders. Along with receptor plasticity, this change in bladder function may involve P2X-independent mechanisms.

Topics: Acetylcholine; Adenosine Triphosphate; Animals; Carbachol; Cholinergic Agonists; Female; Muscarinic Antagonists; Muscle Contraction; Muscle, Smooth; Neuronal Plasticity; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, Muscarinic; Receptors, Purinergic; Spinal Cord Injuries; Urinary Bladder

Neuroprotective and repair strategies in spinal cord injuries (SCIs) have been so far largely unsuccessful. One of the prerequisites is the use of appropriate preclinical models to decipher pathophysiological mechanisms; another is the identification of optimal time windows for therapeutic interventions. The authors undertook this study to characterize early motor, sensory, autonomic, and histological outcomes after balloon compression of the spinal cord at the T8-9 level in adult rats.. A total of 91 rats were used in this study. Spinal cord balloon compression was performed at T8-9 in adult rats by inflation of a 2 Fr Fogarty catheter into the epidural space. The authors first characterized early motor, sensory, and autonomic outcomes of 2 volumes of compression (10 and 15 microl) using behavioral tests and then examined histological outcomes in the spinal cord using Luxol fast blue staining. To further substantiate the characterization of the epidural balloon-compression model, they used a noncompetitive N-methyl-D-aspartate antagonist, GK11, and demonstrated the involvement of excitotoxicity in this model.. Proportional and reproducible functional impairment resulted from compression caused by balloon inflation with either 10 or 15 microl of water and corresponded to the extent of the lesion. Indeed, during the early phase following SCI (1 week postinjury), recovery of locomotor function and bladder control correlated with the volume of inflation, whereas outcomes with respect to sensory function and reflexes were independent of compression severity. Treatment with GK11 significantly improved motor function in all groups of rats 1 week after injury and bladder voiding in the 10-microl injured rats compared to the 15-microl injured rats.. The results of this study demonstrate that spinal balloon-compression injury in the rat is a well-characterized, reproducible, and predictable model to analyze early events following SCI.

Topics: Animals; Autonomic Nervous System; Catheterization; Cyclohexenes; Disease Models, Animal; Excitatory Amino Acid Antagonists; Male; Motor Activity; N-Methylaspartate; Piperidines; Rats; Rats, Wistar; Reflex; Sensory Receptor Cells; Spinal Cord; Spinal Cord Compression; Spinal Cord Injuries; Urination

The NMDA receptor and the brain-derived neurotrophic factor (BDNF) are involved in central sensitization and synaptic plasticity in the spinal cord. To determine whether the spinal cord BDNF contributes to the development and maintenance of neuropathic pain by activation of the dorsal horn NR2B-containing NMDA (NMDA-2B) receptors, this study was designed to investigate if alterations in BDNF and its TrkB receptor in the spinal dorsal horn would parallel the timeline of the development of neuropathic pain in lumbar 5 (L5) spinal nerve ligated (SNL) rats. The enzyme-linked immunosorbent assay (ELISA) showed that the BDNF concentration significantly increased during 24 h post-surgery, and the maximal enhancement lasted for 48 h. It declined as time progressed and returned to the level of pre-operation at 28 days after SNL. In parallel with the alteration of BDNF concentration in the spinal dorsal horn, the 50% paw withdrawal threshold (PWT) of the ipsilateral hind paw in SNL rats also showed a significant decrease during 24-48 h after SNL as compared with those in sham-operated rats. The correlation analysis revealed that the BDNF concentration had a negative correlation with 50% PWT in early stage (0-48 h) (r=-0.974, p=0.001), but not late stage (3-28 days) (r=0.3395, p=0.6605), after SNL. Similarly, the immunohistochemical staining revealed that a significant up-regulation of BDNF expression in the spinal dorsal horn appeared as early as 12 h post-operation in SNL rats, peaked at 24-48 h, declined at 3 days and disappeared at 14 days after SNL. In contrast, an increase in NMDA-2B receptors expression in the spinal dorsal horn was delayed to 48 h after SNL. The increase reached peak at 3 days, lasted for 14 days, and returned to the control level of pre-operation at 28 days after SNL. The maximal enhancement of BDNF expression occurred in early stage (24-48 h) after nerve injury, while the peak of NMDA-2B receptors expression appeared in late stage (3-14 days) post-nerve ligation. As compared with the dynamic changes of 50% PWT in the timeline after nerve injury, the maximal enhancement of BDNF expression closely paralleled the maximal decline in the slope of 50% PWT, while the peak of NMDA-2B receptors expression corresponded with the plateau of the decreased 50% PWT. Therefore, the increased BDNF in the spinal dorsal horn was likely to be associated with the initiation of neuropathic pain in early stage (0-48 h), while the activation of NMDA-2B receptors

Topics: Analysis of Variance; Animals; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Excitatory Amino Acid Antagonists; Gene Expression Regulation; Hyperalgesia; Male; Neuralgia; Pain Measurement; Phenols; Piperidines; Posterior Horn Cells; Rats; Rats, Sprague-Dawley; Receptor, trkB; Receptors, N-Methyl-D-Aspartate; Spinal Cord; Spinal Cord Injuries; Statistics as Topic; Time Factors

1. Previous work indicates that agonists of ghrelin receptors can act within the spinal cord to stimulate autonomic outputs to the colorectum and to blood vessels. Because of the close relationship between colorectal and urinary bladder control, we have investigated whether ghrelin receptor agonists also stimulate spinal centres that influence the bladder. 2. The ghrelin receptor agonist capromorelin (10 mg/kg), injected intravenously in anaesthetized male rats, disrupted the ongoing cycle of micturition reflexes and caused phasic oscillations in pressure that averaged approximately 20 mmHg. Fluid output from the bladder was diminished. The effects of capromorelin were inhibited by hexamethonium (10 mg/kg bolus followed by 4 mg/kg per h infusion, i.v.) and were further reduced by atropine (5 mg/kg bolus followed by 2.5 mg/kg per h infusion, i.v.). Capromorelin (250 microg) injected directly into the spinal cord at the lumbosacral level also increased contractile activity of the bladder. However, capromorelin, up to 0.1 mmol/L, had no effect on the tension of isolated muscle strips from the bladder. Effects of intravenous capromorelin (10 mg/kg) on bladder pressure were still observed after the descending pathways in the spinal cord were disrupted at the thoracic level. 3. In situ hybridization studies revealed ghrelin receptor gene expression in neurons of the autonomic intermediolateral (IML) cell columns. Following a series of micturition reflexes elicited by infusion of saline into the bladder, the immediate early gene product c-Fos was observed in neurons of the lumbosacral IML and approximately 20% of these also expressed ghrelin receptor gene transcripts. 4. It is concluded that ghrelin receptors are expressed by lumbosacral autonomic preganglionic neurons of the micturition reflex pathways and that ghrelin receptor agonists stimulate these neurons.

Topics: Animals; Autonomic Fibers, Preganglionic; Gene Expression; Male; Piperidines; Proto-Oncogene Proteins c-fos; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptors, Ghrelin; Reflex; Spinal Cord; Spinal Cord Injuries; Urinary Bladder; Urination

Topics: Adolescent; Anesthesia Recovery Period; Anesthetics, Intravenous; Ankle Joint; Humans; Piperidines; Postoperative Complications; Propofol; Reflex; Remifentanil; Scoliosis; Spinal Cord Injuries; Young Adult

There is increasing evidence for a role of the cannabinoid (CB) system in the development of neuropathic pain (NP) after spinal cord injury (SCI). The nonspecific CB₁ and CB₂ receptor agonists, WIN 55, 212-2 (WIN), have previously been shown to alleviate both mechanical and thermal hyperalgesia (TH) after peripheral nerve injury.. The present study was designed to identify the CB receptors involved in the antihyperalgesic effect of WIN by using selective antagonists for CB₁ and CB₂ receptors.. This is an in vivo and behavioral study using a moderate T9 contusion SCI. After injury, TH of the hind paws was measured on postinjury days 21 through 42.. Sprague-Dawley rats underwent a contusion SCI using the Multicenter Animal Spinal Cord Injury Study (MASCIS) weight-drop impactor, which induced a moderate T9 SCI. Only animals showing consistent plantar stepping and consistent forelimb and hind limb coordination (Basso, Beattie, and Bresnahan score=15) were tested for TH. Animals exhibiting decreased withdrawal latency time, indicating TH, on or before Day 42, were selected for pharmacological intervention. Animals not exhibiting TH did not receive pharmacological intervention and were sacrificed. Rats underwent hind paw testing before any drug administration (after injury), 45 minutes after selective CB antagonist (AM 251 or AM 630) administration (postantagonist) and again 45 minutes after WIN administration (post-WIN). There were a total of seven treatment groups: saline vehicle control; Dimethyl sulfoxide (DMSO) vehicle control; low-dose WIN (0.2 mg/kg); and high-dose WIN (2.0 mg/kg); AM 251 (3 mg/kg) and AM 630 (1 mg/kg) were given subcutaneously in a total volume of 0.5 mL. Followed by intraperitoneal injection of WIN after each antagonist, sham-operated rats repeated pharmacological intervention used with treatment Groups 5 and 6.. Thermal hyperalgesia was significantly ameliorated in a dose-dependent manner with systemically administered WIN. Cannabinoid receptor Type 1 antagonist AM 251 pretreatment did not affect the antihyperalgesic effect of WIN. By contrast, pretreatment with the CB₂ receptor antagonist AM 630 significantly attenuated the effect of WIN.. Taken together, these results suggest a role of the CB₂ receptor in modulating SCI-induced TH. Selective activation of the CB₂ receptor could potentially lead to analgesic effects on NP while avoiding psychotropic side effects in patients with SCI.

Topics: Analgesics; Analysis of Variance; Animals; Benzoxazines; Dose-Response Relationship, Drug; Hot Temperature; Hyperalgesia; Male; Morpholines; Naphthalenes; Neuralgia; Pain Measurement; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Spinal Cord Injuries

A 12-year-old girl with severe scoliosis underwent an operative procedure for correction of her spine deformity. Spinal cord injury is one of the most feared complications of scoliosis surgery. Therefore, it is necessary to detect spinal injury as early as possible. Intraoperative wake-up test is used to monitor spinal cord function during surgery. We used an intraoperative wake-up test with the concept of target-controlled infusion and total intravenous anesthesia (propofol and remifentanil). The use of Bispectral Index monitoring as a measure of depth of anesthesia enabled the patient to awake rapidly and consequently we did an immediate evaluation of muscle strength of lower extremities.

Topics: Anesthesia, General; Anesthesia, Intravenous; Child; Female; Humans; Intraoperative Complications; Monitoring, Intraoperative; Perioperative Care; Piperidines; Postoperative Complications; Propofol; Remifentanil; Scoliosis; Spinal Cord; Spinal Cord Injuries; Treatment Outcome; Wakefulness

Topics: Animals; Autonomic Nervous System; Disease Models, Animal; Drug Therapy, Combination; Female; Mice; Mice, Inbred C57BL; Motor Activity; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Rimonabant; Spinal Cord Injuries; Urinary Bladder

Spinal cord injury (SCI) pain exhibits many symptoms associated with peripheral neuropathic pain, including increased tactile hypersensitivity. One novel approach to ameliorate SCI pain is the use of cannabinoid (CB) ligands. The current study evaluated the efficacy of the nonselective CB receptor agonist WIN 55,212-2 on tactile hypersensitivity in rats following a brief compression to the thoracic spinal cord. The withdrawal thresholds of the hind paws following SCI were significantly decreased, indicating tactile hypersensitivity. Systemic injection of WIN 55,212-2 increased withdrawal thresholds in a dose-dependent manner. Pretreatment with the CB(1) receptor subtype-selective antagonist AM 251 completely abolished the antinociceptive effect of WIN 55,212-2 whereas pretreatment with the CB(2) receptor subtype-selective antagonist AM 630 did not alter the antinociceptive effect of WIN 55,212-2. These data indicate that a CB(1)-selective agonist may be novel therapeutic treatment for clinical SCI pain.

Topics: Analgesics; Animals; Benzoxazines; Cannabinoid Receptor Agonists; Hindlimb; Hyperesthesia; Male; Morpholines; Naphthalenes; Nociceptors; Pain Threshold; Physical Stimulation; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Spinal Cord Compression; Spinal Cord Injuries; Thoracic Vertebrae

This study tests the hypothesis that central sensitization initiated by nociceptive input can be maintained by repeated brief innocuous peripheral inputs. Capsaicin was injected intradermally into the hind paw of adult rats. Three different types of daily cutaneous mechanical stimulations (vibration, soft brush, or pressure) were applied to the capsaicin-injected paw for a period of 2 weeks. Daily stimulation consisted of a 10-s stimulation repeated every 30s for 30 min. Foot withdrawal thresholds to von Frey stimuli applied to the paw were measured once a day for 4 weeks. The capsaicin-only group (control rats without daily stimulation) showed hyperalgesia lasting for 3 days. In contrast, hyperalgesia persisted for 2 weeks in the group that received vibration stimulation. Neither the soft brush nor the pressure group showed a significant difference in mechanical threshold from the control group (capsaicin only). The vibration-induced prolonged hyperalgesia was significantly reduced by systemic injection of ifenprodil, an NMDA-receptor antagonist, but it was not influenced by either an AMPA-receptor blocker or a reactive oxygen species (ROS) scavenger. Furthermore, a dorsal column lesion did not interfere with the prolongation of hyperalgesia. Data suggest that vibration-induced prolongation of hyperalgesia is mediated by spinal NMDA-receptors, and a similar mechanism may underlie some forms of chronic pain with no obvious causes, such as complex regional pain syndrome type 1 (CRPS-1).

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Analysis of Variance; Animals; Behavior, Animal; Capsaicin; Drug Interactions; Excitatory Amino Acid Antagonists; Hyperalgesia; Male; Pain Measurement; Pain Threshold; Physical Stimulation; Piperidines; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Time Factors; Vibration

Spinal cord injury (SCI) causes delayed secondary biochemical alterations that lead to tissue loss and associated neurological dysfunction. Up-regulation of cell cycle proteins occurs in both neurons and glia after SCI and may contribute to these changes. The present study examined the role of cell cycle activation on secondary injury after severe SCI in rat. SCI caused cell cycle protein up-regulation associated with neuronal and oligodendroglial apoptosis, glial scar formation and microglial activation. Treatment with the cell cycle inhibitor flavopiridol reduced cell cycle protein induction and significantly improved functional recovery versus vehicle-treated controls at 21 and 28 days post-injury. Treatment also significantly reduced lesion volume, as measured by MRI and histology, decreased astrocytic reactivity, attenuated neuronal and oligodendroglial apoptosis and reduced the production of factors associated with microglial activation. Thus, flavopiridol treatment improves outcome after SCI by inhibiting cell cycle pathways, resulting in beneficial multifactorial actions on neurons and glia.

Topics: Animals; Apoptosis; Astrocytes; Blotting, Western; Cell Cycle; Cell Cycle Proteins; Flavonoids; Immunohistochemistry; Injections, Spinal; Magnetic Resonance Imaging; Male; Models, Animal; Neuroglia; Oligodendroglia; Piperidines; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Up-Regulation

Transcranial magnetic stimulation with motor evoked potential monitoring is a non-invasive method for monitoring motor tracts during surgery. However, anaesthetic agents such as propofol and volatile agents reduce responses to single transcranial magnetic stimulation. We assessed an intravenous technique for anaesthesia to allow motor evoked potentials (MEPs) to be monitored using repetitive transcranial magnetic stimulation (rTMS).. We applied three-pulse rTMS (TriStim) in 11 patients undergoing spinal column surgery after spinal column injury and recorded the latency and peak-to-peak amplitude of MEPs. Anaesthesia was maintained with propofol and remifentanil.. MEPs were monitored successfully intraoperatively in all patients.. It is possible to monitor intraoperative MEP using rTMS during anaesthesia with propofol and remifentanil.

Topics: Adolescent; Adult; Anesthesia, Intravenous; Anesthetics, Combined; Anesthetics, Intravenous; Evoked Potentials, Motor; Female; Humans; Male; Middle Aged; Monitoring, Intraoperative; Piperidines; Propofol; Reaction Time; Remifentanil; Spinal Cord; Spinal Cord Injuries; Transcranial Magnetic Stimulation

Centrally expressed 5-HT3 receptors (5-HTR3) are well known for their role in wakefulness, cognition, and nociception. However, clear evidence of their participation in motor control is still lacking despite specific 5-HTR3 expression in hindlimb motor areas of the spinal cord (i.e., lumbar laminae VII-IX). Here, we studied the acute effects of 4-amino-(6-chloro-2-pyridyl)-1-piperidine hydrochloride (SR 57227A), a potent and selective 5-HTR3 agonist, on hindlimb movement generation in complete paraplegic mice. The induced movements were assessed in open-field, air-stepping, and treadmill conditions using a combination of qualitative and quantitative methods. The results revealed that SR 57227A (1-4 mg/kg ip) produced hindlimb movements corresponding to scores ranging from 1 to 5 on the motor scales of Basso, Beattie, and Bresnahan and of Antri, Orsal, and Barthe. Additional analyses revealed that one-third of the movements displayed on a treadmill were "locomotor-like" (i.e., bilateral alternation), whereas only nonlocomotor movements were observed in the other testing conditions suggesting a task-dependent contribution of peripheral afferent inputs to these effects. Locomotor-like movements could also be induced in open field and air stepping if SR 57227A was combined with subthreshold doses of 5-carboxytryptamine (5-HT1A/7 receptor agonist), suggesting synergistic actions of these drugs on central neurons. These results demonstrate that 5-HTR3 activation can induce motor activity and, under some conditions, rhythmic locomotor-like movements in the hindlimbs of paraplegic mice providing evidence of an unsuspected role for this receptor subtype in hindlimb motor control.

Topics: Animals; Biological Clocks; Hindlimb; Injections, Intraperitoneal; Ion Channels; Locomotion; Male; Mice; Muscle Contraction; Muscle, Skeletal; Paraplegia; Piperidines; Receptors, Serotonin, 5-HT3; Serotonin Receptor Agonists; Spinal Cord Injuries

Increased afferent nerve activity may have an important role in the pathogenesis of neurogenic detrusor overactivity. We tested the efficacy of the neuokinin-2 receptor antagonist M274773 ((S)-N-[2-(3,4-Dichlorophenyl)-4-[4-(2-oxoperhydro-pyrimidin-l-yl) piperidino]butyl]-N-methylbenzamide dihydrochloride) on neurogenic detrusor overactivity after spinal cord injury in rats.. Included in this study were 48 adult Sprague-Dawley rats (Charles River, Montreal, Quebec, Canada). Six animals served as normal controls, while 32 underwent spinal cord transection at the 10th thoracic vertebra. Two weeks after spinal cord injury 6 animals underwent filling cystometrography to confirm neurogenic detrusor overactivity, while another 12 served as paraplegic controls. The remaining 24 paraplegic animals were used to test the drug and they were divided into 2 equal groups of 12. Group 1 received the drug at a dose of 0.3 mg/kg daily, while group 2 received a dose of 0.6 mg/kg daily. Each paraplegic control and treatment group was further subdivided into 2 subgroups of 6 rats each. In subgroup 1 filling cystometrography was done 3 weeks after spinal cord injury, while in subgroup 2 it was done 4 weeks after spinal cord injury.. Three weeks after spinal cord injury neurogenic detrusor overactivity developed in all paraplegic control animals with a mean bladder capacity +/- SD of 0.7 +/- 0.2 ml and a mean voiding pressure of 59 +/- 14.2 cm H2O. Neurogenic detrusor overactivity resolved in 50% and 83% of the animals that received M274773 for 1 week at doses of 0.3 and 0.6 mg/kg daily, respectively. Mean cystometric bladder capacity was 1.2 +/- 0.5 vs 1.3 +/- 0.4 ml and mean voiding pressure was 46.1 +/- 10.8 vs 40 +/- 9.9 cm H2O in animals that received 0.3 vs 0.6 mg/kg daily, respectively. The drug produced better urodynamic results when given for 2 weeks rather than 1 week.. M274773 is effective for neurogenic detrusor overactivity after spinal cord injury in the rat. It may provide an alternative clinical treatment option for neurogenic detrusor overactivity and urgency/frequency syndrome. This new neurokinin-2 selective antagonist has time and dose response effects, which further suggests the potential for clinical application.

Topics: Animals; Benzamides; Dose-Response Relationship, Drug; Female; Piperidines; Pyrimidines; Rats; Rats, Sprague-Dawley; Receptors, Neurokinin-2; Reflex, Abnormal; Spinal Cord Injuries; Urinary Bladder; Urinary Bladder, Neurogenic; Urodynamics

Windup, the frequency dependent build-up of spinal neuronal responses, is implicated in the development of central sensitization of nociceptive pathways. N-methyl-D-aspartate (NMDA) receptors have been shown to be involved in these processes but the role of various receptor subtypes at the spinal level is not fully understood. In our experiments, we compared the inhibitory effect of MK-801 (a nonselective NMDA receptor antagonist, 0.01-3 mg/kg i.v.) and CI-1041 (an NR2B subunit specific NMDA receptor antagonist, 0.3-10 mg/kg i.v.) on the formation of dorsal horn neuronal windup in spinalized rats, in vivo. Both types of antagonist blocked windup considerably at doses not affecting the normal synaptic transmission. These results are in agreement with the well-documented effectivity of NR2B subtype selective NMDA receptor antagonists in chronic pain models and give the first direct evidence that spinal mechanisms are involved in this effect.

Topics: Action Potentials; Analysis of Variance; Animals; Benzoxazoles; Dizocilpine Maleate; Dose-Response Relationship, Drug; Drug Interactions; Electric Stimulation; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Male; Nerve Fibers; Piperidines; Posterior Horn Cells; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Spinal Cord; Spinal Cord Injuries

We hypothesized that neuropeptides released from the peripheral terminals of primary afferents play an important role in mechanical hyperalgesia after peripheral nerve injury. Nerve injury was performed on rats with lumbar 5 spinal nerve lesion (L5 SNL), which was preceded by L5 dorsal rhizotomy (L5 DR) to avoid the potential central effects induced by L5 SNL through the L5 dorsal root. L5 DR produced a short-lasting (<6 days) decrease in paw withdrawal threshold (PWT) while the following L5 SNL produced a persistent (>42 days) PWT decrease. When intraplantar injection to the affected hind paw was given immediately before L5 SNL, antagonists for both neurokinin 1 (NK1) and calcitonin gene-related peptide 1 (CGRP1) receptors delayed the onset of the PWT decrease for 2-4 days. However, when the same injection was given after L5 SNL, CGRP1, but not NK1, receptor antagonist reversed the decreased PWT for 105 min. It is suggested that peripherally released neuropeptides contribute to the generation of neuropathic pain, with substance P and CGRP contributing to its induction phase, but only CGRP to its maintenance phase.

Topics: Analysis of Variance; Animals; Calcitonin Gene-Related Peptide; Disease Models, Animal; Functional Laterality; Hyperalgesia; Lumbosacral Region; Male; Pain Measurement; Pain Threshold; Peptide Fragments; Piperidines; Rats; Rats, Sprague-Dawley; Rhizotomy; Spinal Cord Injuries; Statistics, Nonparametric; Substance P; Time Factors

The selective, high-efficacy 5-HT(1A) receptor agonist, (3-chloro-4-fluoro-phenyl)-[4-fluoro-4-[[(5-methyl-pyridin-2-ylmethyl)-amino]-methyl]piperidin-1-yl]-methanone (F 13640) has been reported to produce long-term analgesia in rodent models of chronic nociceptive and neuropathic pain; it also preempts allodynia following spinal cord injury. Here, rats underwent spinal cord injury, fully developed allodynia, and were infused with saline or 0.63 mg/day of F 13640 for 56 days. Infusion was then discontinued, and further assessments of allodynia (vocalization threshold to von Frey filament stimulation, responses to brush and cold) were conducted for another 70 days. F 13640-induced analgesia persisted during this post-treatment period. The data offer initial evidence that high-efficacy 5-HT(1A) receptor activation produces an unprecedented curative-like action on pathological pain.

Topics: Analgesics; Animals; Behavior, Animal; Cold Temperature; Female; Infusions, Intravenous; Pain; Pain Measurement; Pain Threshold; Piperidines; Pyridines; Rats; Rats, Sprague-Dawley; Serotonin 5-HT1 Receptor Agonists; Spinal Cord Injuries; Touch; Vocalization, Animal

Muscarinic facilitation of 14C-ACh release from post-ganglionic parasympathetic nerve terminals was studied in bladder strips prepared from spinal intact (SI) and spinal cord transected (SCT) rats. The spinal cord was transected at the lower thoracic spinal segments 3 weeks prior to the experiments. Using non-facilitatory stimulation (2 Hz) the release of ACh in spinal intact rats did not change in the presence of a non-specific muscarinic antagonist, atropine (100 nM), an M(1) specific antagonist (pirenzepine, 50 nM) or an M(1)-M(3) specific antagonist (4-DAMP, 5 nM). However, during a facilitatory stimulation paradigm (10 Hz or 40 Hz, 100 shocks) atropine and pirenzepine, but not 4-DAMP inhibited the release of ACh in bladders from spinal intact rats, indicating an M(1) receptor-mediated facilitation. In spinal cord transected rats, 2 Hz stimulation-induced release was significantly inhibited by atropine or 4-DAMP but not by pirenzepine indicating that a pre-junctional facilitatory mechanism mediated via M(3) muscarinic receptors could be induced by a non-facilitatory stimulation paradigm after spinal injury. In bladders of spinal cord transected rats, 10 Hz stimulation-evoked release of ACh was also inhibited by atropine and 4-DAMP (5 nM) but not by pirenzepine (50 nM). These results indicate that pre-junctional muscarinic receptors at cholinergic nerve endings in the bladder change after chronic spinal cord injury. It appears that low affinity M(1) muscarinic receptors are replaced by high affinity M(3) receptors. This change in modulation of ACh release may partly explain the bladder hyperactivity after chronic spinal cord injury.

Topics: Animals; Atropine; Electric Stimulation; Female; Muscarinic Antagonists; Neurotransmitter Agents; Piperidines; Pirenzepine; Rats; Rats, Sprague-Dawley; Receptor, Muscarinic M3; Receptors, Muscarinic; Spinal Cord Injuries; Urinary Bladder; Urinary Bladder, Neurogenic

Motor evoked potentials can be affected by propofol anaesthesia. We studied how increasing target concentrations of propofol altered transcranial motor evoked potentials (tcMEP) during scoliosis surgery.. Fifteen patients undergoing surgery for scoliosis were anaesthetized with remifentanil and propofol without nitrous oxide or neuromuscular blocking agents (BIS<60). tcMEP were elicited by transcranial electric multipulse stimulation of the motor cortex and recording of compound action potentials from the anterior tibialis muscle. tcMEP were obtained before surgery with propofol target values set from 4 to 8 mg litre(-1), and then during surgery. Arterial propofol concentrations were measured for each tcMEP recording.. Before surgery, increasing propofol reduced tcMEP amplitude in a dose-dependent manner, with no effect on latency. During surgery, at equivalent propofol concentrations, tcMEP were not statistically different from those obtained before surgery. In all except one patient, tcMEP signals were present during the entire procedure. In this patient the loss of tcMEP was unfortunately related to an anterior spinal cord lesion, which was confirmed by a wake-up test.. We found that, although propofol had a dose-dependent effect on tcMEP amplitude, anaesthesia could be maintained with remifentanil and propofol to allow recording and interpretation of tcMEP signals.

Topics: Adult; Analgesics, Opioid; Anesthetics, Intravenous; Dose-Response Relationship, Drug; Electric Stimulation; Evoked Potentials, Motor; Female; Humans; Male; Motor Cortex; Piperidines; Propofol; Remifentanil; Scoliosis; Spinal Cord Injuries; Statistics, Nonparametric

Central neuropathic pain after spinal cord injury (SCI) presents a challenging clinical problem with limited treatment options. [(3-chloro-4-fluoro-phenyl)-[4-fluoro-4-([(5-methyl-pyridin-2-ylmethyl)-amino]-methyl)piperidin-1-yl]]-methadone (F 13640) is a recently discovered very-high-efficacy, selective 5-HT1A receptor agonist that produces a remarkably powerful, central analgesia through unprecedented neuroadaptive mechanisms. In a rat model of spinal cord injury pain, we previously found that chronic infusion of F 13640 alleviated pain-like behaviors. Here, we report that infusion of 0.63 mg/day of F 13640 for 8 weeks starting 24 h before the induction of injury significantly attenuates the development of chronic allodynia-like behavior in rats sustaining a photochemically-induced, ischaemic injury of the dorsal laminae of the L3-L5 segments of the spinal cord. Importantly, the preemptive effect of F 13640 persisted for 2 months after treatment was discontinued. The data warrant the study of the possible effects of the early administration of F 13640 in patients sustaining spinal cord injury.

Topics: Animals; Behavior, Animal; Cold Temperature; Female; Motor Activity; Pain; Pain Measurement; Pain Threshold; Photochemistry; Physical Stimulation; Piperidines; Pyridines; Rats; Rats, Sprague-Dawley; Receptor, Serotonin, 5-HT1A; Serotonin Receptor Agonists; Spinal Cord Injuries; Time Factors; Vocalization, Animal

The pharmacokinetics of gacyclidine enantiomers, a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, were studied in plasma and spinal cord extracellular fluid (ECF) after experimental spinal cord injury in rats. Spinal cord trauma was produced by introducing an inflatable balloon in the dorsal subdural space. Upon implantation of microdialysis probes in spinal cord (T9) and intravenous (iv) bolus administration of (+/-)-gacyclidine (2.5 mg/kg), concentrations in plasma and ECF were monitored over 5 h and analyzed by a stereospecific gas chromatography-mass spectrometry (GC-MS) assay. In plasma, concentrations of (+)-gacyclidine were approximately 25% higher than those of (-)-gacyclidine over the duration of the experiment and decayed in parallel (t(1/2 alpha) approximately 7 min; t(1/2 beta) approximately 90 min) with no significant difference between the two enantiomers. Clearance (CL) and volume of distribution (Vd) of (-)-gacyclidine were approximately 20% higher than those of its optical antipode (CL: 285 versus 236 mL. kg(-1). min(-1); Vd(beta): 39.3 versus 31.2 l/kg). Protein binding (approximately 91%) was not stereoselective. In spinal cord ECF, both enantiomers were quantifiable within 10 min after drug administration, and their concentration remained stable over the duration of the experiment in spite of changing blood concentrations. Repeated iv bolus injections of gacyclidine did not modify these profiles. Areas under the curves (AUCs) of concentration in ECF versus time were similar for both enantiomers and not correlated with AUCs in plasma. Penetration of (-)-gacyclidine was, however, significantly higher (approximately 30%) than that of (+)-gacyclidine. In summary, the disposition of gacyclidine enantiomers is stereoselective. Both enantiomers exhibit a high affinity for spinal cord tissue, and the drug exchange between plasma and spinal cord ECF involves an active transport system. These findings contribute to the explanation of the discrepancy between drug concentrations in plasma and spinal cord ECF.

Topics: Animals; Biological Transport, Active; Calibration; Cyclohexanes; Cyclohexenes; Disease Models, Animal; Dose-Response Relationship, Drug; Male; Neuroprotective Agents; Piperidines; Protein Binding; Rats; Rats, Wistar; Spinal Cord Injuries; Stereoisomerism; Tissue Distribution

The present experiments were designed to investigate the role(s) of cannabinoid receptors in modulating transmission in the sural-medial gastrocnemius withdrawal reflex of the decerebrated, spinalized rabbit and how, if present, cannabinoid-mediated control might interact with opioid-mediated inhibitions known to impinge on this reflex pathway. The selective CB(1) receptor antagonist SR 141716A enhanced reflexes by a factor of two after a cumulative dose of 100 nmol kg(-1) i.v., but had no effect on the endogenous opioid-mediated inhibition generated by repetitive electrical stimulation of the common peroneal nerve, or on the suppression of reflexes caused by i.v. administration of the synthetic opioid fentanyl. Given at a dose of 10 nmol kg(-1) i.v., the potent, CB(1)--CB(2) cannabinoid receptor agonist HU 210 inhibited medial gastrocnemius reflexes to approximately 30% of controls and significantly decreased both heart rate and blood pressure, but did not alter the inhibition of reflexes resulting from common peroneal nerve stimulation or i.v. fentanyl. The effects of HU 210 were reversed by SR 141716A. HU 210 was just as effective in inhibiting reflexes in the presence of the opioid antagonist naloxone (5 micromol kg(-1)) as it was in untreated animals. The data show that cannabinoids, acting through CB(1) receptors, are inhibitory in rabbit spinal cord and that there appears to be some endogenous cannabinoid tone under the conditions of the present experiments. The evidence of this study is that the inhibitory effects of opioids and cannabinoids in rabbit spinal cord are completely independent of each other, and are additive rather than synergistic.

Topics: Animals; Decerebrate State; Dose-Response Relationship, Drug; Dronabinol; Female; Fentanyl; Male; Naloxone; Narcotic Antagonists; Piperidines; Pyrazoles; Rabbits; Receptors, Cannabinoid; Receptors, Drug; Reflex; Rimonabant; Spinal Cord; Spinal Cord Injuries

The aim of this study was to evaluate the efficacy, optimal dose, and optimal time-window of gacyclidine, a novel N-methyl-D-aspartate (NMDA) receptor antagonist, in terms of its functional, histopathological, and electrophysiological effects after experimental spinal cord injury. The spinal cord of rats was damaged by a photochemical method and the animals were treated by saline or gacyclidine at doses of 1, 2.5, or 5 mg/kg 10 min after injury or gacyclidine 1 mg/kg 10, 30, 60, and 120 min after injury. The time-course of the motor score (walking and inclined-plane stability) was evaluated until day 18, and somatosensory evoked potentials were determined on day 18. The animals were then sacrificed, and the cross-sectional area of the spinal cord (at the epicenter of the injury, above and below the injury) was measured. Walking recovery was better in most of the groups treated after injury than in the untreated injured animals. Motor performances were related to preservation of a larger undamaged area of spinal cord at the level of the injury and, interestingly, with prevention of extension of the anatomical lesion above the level of the injury. Somatosensory evoked potential amplitudes were often higher in treated groups. These results confirm that gacyclidine induces dose-dependent and time-dependent attenuation of spinal cord damage after an experimental vascular lesion. Although all three doses induced neuroprotective effects, recovery was greater and very homogeneous in the group treated with 1 mg/kg. Moreover, recovery was slightly better and more homogeneous within the groups treated 10 and 30 min after injury compared to the other groups. It appears that, according to the existing evidence, NMDA antagonists are an essential component in the elaboration of a neuroprotective strategy after spinal cord trauma.

Topics: Animals; Cyclohexanes; Cyclohexenes; Disease Progression; Dose-Response Relationship, Drug; Evoked Potentials, Somatosensory; Excitatory Amino Acid Antagonists; Light Coagulation; Male; Motor Activity; Neuroprotective Agents; Piperidines; Rats; Rats, Sprague-Dawley; Reaction Time; Receptors, N-Methyl-D-Aspartate; Spinal Cord; Spinal Cord Injuries; Spinal Cord Ischemia

The aim of this study was to analyze the optimal time-window for neuroprotection by a novel NMDA antagonist, Gacyclidine, after experimental spinal cord injury, in terms of its functional, histopathological and electrophysiological effects. This molecule has already demonstrated its capacity for reducing the extent of an ischemic lesion and is currently experimented in a clinical trial of spinal cord injury. In this study, the spinal cord of rats was damaged by a contusive method and the animals were treated by saline or 1 mg/kg of Gacyclidine i.v., 10, 30, 60 and 120 min after injury. The time-course of the motor score was evaluated on days 1, 7 and 18 after injury, and somatosensory evoked potentials were determined on day 20. The animals were then killed and the cross-sectional area of the spinal cord (at the epicenter of the injury, above and below the injury), was measured. Walking recovery was better (P<0.0125) in the group treated 10 min after injury than in the untreated injured animals after 18 days of injury. Motor performances were related to the preservation of a larger undamaged area of spinal cord at the level of the injury (P<0.0125). Somatosensory evoked potential amplitudes were also higher in this group. These results confirm that Gacyclidine attenuates spinal cord damage after an experimental spinal cord lesion. Recovery was better within the group treated 10 min after injury compared with the other groups, which certainly confirms that the acute time-course of glutamate release requires rapid pharmacological intervention to achieve good results.

Topics: Animals; Contusions; Cyclohexanes; Cyclohexenes; Electrophysiology; Evoked Potentials, Somatosensory; Excitatory Amino Acid Antagonists; Male; Motor Activity; N-Methylaspartate; Neuroprotective Agents; Piperidines; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Time Factors; Weight Gain

Prevention of the immediate excitotoxic phase occurring in response to spinal cord injury (SCI) is a major issue to reduce the neuronal damage responsible for any ensuing motor deficits. The present study evaluated the neuroprotective efficacy of three noncompetitive NMDA receptor antagonists: Gacyclidine (GK-11), a new compound, Dizocilpine (MK-801), and Cerestat (CNS-1102) in a rat spinal cord contusion model. To mimic human SCI, a standardized model of rat spinal cord closed contusion in which animals spontaneously and progressively recover from the induced paraplegia was employed. Such model, characterized by a slow recovery of hindlimb locomotor function enables easy quantification of the neuroprotection at both the behavioral and cellular level. The animals were treated intravenously with the respective drugs 10 min after the spinal contusion. The dose range study suggested that 1 mg/kg of Gacyclidine was the most effective dose to promote functional recovery in reducing by half the time needed to reach full locomotor recovery. Racemate and enantiomers of Gacyclidine showed similar neuroprotective effects, but treatment with the enantiomers were not as efficacious in promoting full functional recovery. Similarly, a prolonged treatment with the racemate was not as efficious as a single dose, suggesting that a prolonged blockade of the amino-excitatory neurotransmission may be deleterious. Finally, Dizocilpine and Cerestat treatments induced only a partial and delayed neuroprotective effect compared to Gacyclidine. Neuroprotection characterized by a reduction of the cystic cavity and of the astrogliosis was observed with all treatments. As Gacyclidine is already in clinical trials, the present findings suggest the premise that it is a promising agent for limiting the initial neuronal damage induced by CNS trauma leading to better functional recovery.

Topics: Animals; Astrocytes; Cyclohexanes; Cyclohexenes; Dizocilpine Maleate; Dose-Response Relationship, Drug; Drug Administration Schedule; Excitatory Amino Acid Antagonists; Female; Gliosis; Guanidines; Neuroprotective Agents; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Stereoisomerism

In vitro bladder contractions in response to cumulative carbachol doses were measured in the presence of selective muscarinic antagonists from rats which had their major pelvic ganglion bilaterally removed (denervation, DEN) or from rats in which the spinal cord was injured (SCI) via compression. DEN induced both hypertrophy (505+/-51 mg bladder weight) and a supersensitivity of the bladders to carbachol (EC50=0.7+/-0.1 uM). Some of the SCI rats regained the ability to void spontaneously (SPV). The bladders of these animals weighed 184+/-17 mg, significantly less than the bladders of non voiding rats (NV, 644+/-92 mg). The potency of carbachol was greater in bladder strips from NV SCI animals (EC50=0.54+/-0.1 uM) than either bladder strips from SPV SCI (EC50=0.93+/-0.3 microM), DEN or control (EC50=1.2+/-0.1 microM) animals. Antagonist affinities in control bladders for antagonism of carbachol induced contractions were consistent with M3 mediated contractions. Antagonist affinities in DEN bladders for 4-diphenlacetoxy-N-methylpiperidine methiodide (4-DAMP, 8.5) and para fluoro hexahydrosilodifenidol (p-F-HHSiD, 6.6); were consistent with M2 mediated contractions, although the methoctramine affinity (6.5) was consistent with M3 mediated contractions. p-F-HHSiD inhibited carbachol induced contraction with an affinity consistent with M2 receptors in bladders from NV SCI (pKb=6.4) animals and M3 receptors in bladders from SPV SCI animals (pKb=7.9). Subtype selective immunoprecipitation of muscarinic receptors revealed an increase in total and an increase in M2 receptor density with no change in M3 receptor density in bladders from DEN and NV SCI animals compared to normal or sham operated controls. M3 receptor density was lower in bladders from SPV SCI animals while the M2 receptor density was not different from control. This increase in M2 receptor density is consistent with the change in affinity of the antagonists for inhibition of carbachol induced contractions and may indicate that M2 receptors or a combination of M2 and M3 receptors directly mediate smooth muscle contraction in bladders from DEN and NV SCI rats.

Topics: Animals; Binding Sites; Carbachol; Diamines; Dose-Response Relationship, Drug; Female; Hypertrophy; Muscarinic Agonists; Muscarinic Antagonists; Muscle Contraction; Muscle Denervation; Muscle, Smooth; Organ Size; Piperidines; Rats; Rats, Sprague-Dawley; Receptor, Muscarinic M2; Receptors, Muscarinic; Spinal Cord Injuries; Urinary Bladder; Urinary Bladder, Neurogenic

We report the case of a 75 old man with chronic constipation due to traumatic spinal cord injury 25 years ago. Following prostatectomy the patient developed retention of urine and urinary incontinence, which improved significantly during a therapy with cisapride (3 x 10 mg/day). While the administration of cisapride is associated with increased detrusor activity and possibly urinary incontinence in neurologically normal persons, patients with urinary retention due to spinal cord injury may benefit from a therapy with this indirect parasympathomimetic agent.

Topics: Aged; Cisapride; Constipation; Humans; Male; Parasympathomimetics; Piperidines; Spinal Cord Injuries; Urinary Retention

Chronic constipation in patients with spinal cord injury (SCI) has significant impact on quality of life. To measure baseline clinical functioning, colonic transit time and anorectal manometry and the effect of cisapride on these clinical and physiological parameters, we studied 12 SCI patients. Patients initially received baseline clinical scoring, measurement of colonic transit time and anorectal manometry. Patients then received cisapride 20 mg orally three times each day. After one and three months of cisapride therapy, all measurements were repeated. The mean duration cisapride treatment was 5.2 months. Six of 12 (50 percent) reported that symptoms of constipation improved. No patient had worsening of symptoms. Prior to cisapride treatment, 23 percent of patients passed colonic transit markers by day five and 57 percent by day seven; baseline anal manometry revealed variable resting and squeeze pressures. After treatment, 33 percent of patients passed their colonic transit markers by day five and 71 percent by day seven. Six of 12 (50 percent) demonstrated a 10 percent or more increase in resting anal canal pressures. We conclude that about 50 percent of SCI patients have subjective improvement in constipation after cisapride therapy. Cisapride appears to improve both colonic and anorectal function.

Topics: Cisapride; Colostomy; Constipation; Gastrointestinal Motility; Gastrointestinal Transit; Humans; Manometry; Paraplegia; Parasympathomimetics; Piperidines; Quadriplegia; Spinal Cord Injuries

The effect of cisapride on constipation in para and tetraplegia is well known. We have investigated the effects of this prokinetic drug on anorectal activity and on the function of the lower urinary tract. One result of the anorectal study showed a significant increase in activity and a reduction in compliance of the ampulla. The urodynamic study demonstrated earlier and higher amplitude reflex contractions in hyperactive bladders; hypoactive bladders significantly reduced their compliance. No functional alterations of striated urethral sphincter were observed.

Topics: Anal Canal; Cisapride; Female; Gastrointestinal Diseases; Gastrointestinal Transit; Humans; Male; Piperidines; Rectum; Serotonin Antagonists; Spinal Cord Injuries; Urethra; Urodynamics

Two patients with intractable constipation and an atonic bladder due to a partial spinal cord lesion and sacral nerve lesion are described. Treatment with cisapride (4 x 10 mg daily) was undertaken. After a few days the stool passed spontaneously. The effect was dose-dependent and has been maintained for at least 40 months. Normal bladder function was not achieved.

Topics: Adult; Chronic Disease; Cisapride; Constipation; Dose-Response Relationship, Drug; Gastrointestinal Transit; Humans; Lumbosacral Plexus; Male; Middle Aged; Piperidines; Spinal Cord Injuries; Urinary Bladder, Neurogenic

We describe the case of a paraplegic patient who suffered traumatic spinal cord injury at the level of the twelfth thoracic vertebra. Within a short period of time following the injury, urinary (neuropathic bladder) and gastrointestinal (atomic colon) sequelae arose. Treatment with Cisapride (R 51 619, Janssen Pharmaceutica) was undertaken in an attempt to increase colonic motility and to reduce urinary retention. These goals were reached rapidly with a dose of 10 mg q.i.d.; the effect has been maintained for at least 18 months since starting the therapy.

Topics: Bisacodyl; Cisapride; Constipation; Drug Administration Schedule; Drug Therapy, Combination; Humans; Male; Middle Aged; Piperidines; Spinal Cord Injuries; Urinary Bladder, Neurogenic