sodium-oxybate and Disease-Models--Animal

Typical absence seizures (ASs) are nonconvulsive epileptic events which are commonly observed in pediatric and juvenile epilepsies and may be present in adults suffering from other idiopathic generalized epilepsies. Our understanding of the pathophysiological mechanisms of ASs has been greatly advanced by the availability of genetic and pharmacological models, in particular the γ-hydroxybutyrate (GHB) model which, in recent years, has been extensively used in studies in transgenic mice. GHB is an endogenous brain molecule that upon administration to various species, including humans, induces not only ASs but also a state of sedation/hypnosis. Analysis of the available data clearly indicates that only in the rat does there exist a set of GHB-elicited behavioral and EEG events that can be confidently classified as ASs. Other GHB activities, particularly in mice, appear to be mostly of a sedative/hypnotic nature: thus, their relevance to ASs requires further investigation. At the molecular level, GHB acts as a weak GABA-B agonist, while the existence of a GHB receptor remains elusive. The pre- and postsynaptic actions underlying GHB-elicited ASs have been thoroughly elucidated in thalamus, but little is known about the cellular/network effects of GHB in neocortex, the other brain region involved in the generation of ASs.

Topics: Adjuvants, Anesthesia; Animals; Brain; Disease Models, Animal; Dose-Response Relationship, Drug; Epilepsy, Absence; Humans; Sodium Oxybate

A liquid formulation of sodium oxybate (Alcover(®)), the sodium salt of γ-hydroxybutyric acid (GHB), is approved in Italy and Austria for use in alcohol withdrawal syndrome and for the maintenance of abstinence in alcohol dependence. This article reviews the efficacy and tolerability of sodium oxybate in alcohol withdrawal syndrome and in the maintenance of abstinence in alcohol dependence, as well as summarizing its pharmacological properties. Results of randomized controlled trials indicate that sodium oxybate was at least as effective as diazepam and clomethiazole in patients with alcohol withdrawal syndrome, rapidly alleviating symptoms, and was at least as effective as naltrexone or disulfiram in the maintenance of abstinence in alcohol-dependent patients. Sodium oxybate was generally well tolerated. The risk of sodium oxybate abuse is generally low when it is administered to alcohol-dependent patients at its approved dosage, under the supervision of a designated family member and with continuous strict medical surveillance. However, certain patient groups, such as patients with alcohol dependence and borderline personality disorder or who are in remission from heroin or cocaine addiction, may not be suitable candidates for sodium oxybate therapy because of an increased risk of abuse. In conclusion, sodium oxybate is a useful option for the treatment of alcohol withdrawal syndrome and for the maintenance of abstinence in alcohol dependence.

Topics: Alcohol Abstinence; Alcohol Deterrents; Alcohol Drinking; Alcoholism; Animals; Behavior, Addictive; Disease Models, Animal; Drug Interactions; Humans; Sodium Oxybate; Substance Withdrawal Syndrome

Narcolepsy is an emblematic, unique disease within sleep disorders that is characterised by excessive daytime sleepiness, cataplexy and other abnormal manifestations of REM sleep. In the last 14 years truly spectacular progress has been made in our knowledge of this disease, since the discovery of its cause, i.e. a loss of the hypothalamic neurons that synthesise hypocretin, a previously unknown neurotransmitter, and its probable aetiopathogenic mechanisms, i.e. an autoimmune process in a patient with very precise immunological characteristics - a specific type of HLA and a specific type of T-cell receptor. The cause of this autoimmune process remains unknown. The definitive treatment - the administration of hypocretin, which is the substance missing in the organism - is still unavailable, but there are powerful drugs for treating its main symptoms, the sleepiness and the cataplexy. Some of these are classic compounds (methylphenidate, clomipramine), while others are more recent (modafinil, venlafaxine, sodium oxybate), but together they allow many patients to experience significant improvements. Lack of knowledge about the disease, both on the part of patients and their relatives as well as physicians, is the reason for the great delay in its diagnosis, with even more dramatic consequences when the disease begins in infancy.

Topics: Adolescent; Adult; Age of Onset; Animals; Autoimmune Diseases; Benzhydryl Compounds; Cataplexy; Child; Clomipramine; Cyclohexanols; Delayed Diagnosis; Disease Models, Animal; Dogs; Genetic Predisposition to Disease; Histamine Agonists; HLA-DQ Antigens; HLA-DQ beta-Chains; Humans; Hypothalamus; Immunoglobulins, Intravenous; Intracellular Signaling Peptides and Proteins; Methylphenidate; Modafinil; Narcolepsy; Neuropeptides; Orexins; Polysomnography; Receptors, Antigen, T-Cell; Sodium Oxybate; Venlafaxine Hydrochloride

SSADH deficiency, a rare inborn error of human metabolism, disrupts the normal metabolism of the inhibitory neurotransmitter GABA. In response to the defect, physiologic fluids from patients accumulate GHB, a compound with numerous neuromodulatory properties. Clinical and bio-chemical findings in patients are contrasted with existing neuropharmacologic data on GHB in animals and men. We conclude that GHB contributes to the pathogenesis of SSADH deficiency; whether this effect is mediated by GHB, by GABA following metabolic interconversion, or via synergistic mechanisms by both compounds, remains to be determined. An animal model of SSADH deficiency should further define the role of GHB in the pathogenesis of SSADH deficiency, and provide a useful vehicle for the evaluation of new therapeutic intervention.

Topics: Aldehyde Oxidoreductases; Animals; Anticonvulsants; Child; Developmental Disabilities; Disease Models, Animal; Electroencephalography; gamma-Aminobutyric Acid; Humans; Illicit Drugs; Metabolism, Inborn Errors; Phenotype; Sodium Oxybate; Succinate-Semialdehyde Dehydrogenase; Vigabatrin

A number of animal models of generalized absence seizures in rodents are described. These include absence seizures induced by gamma-hydroxybutyrate (GHB), low dose pentylenetetrazole, penicillin, THIP, and AY-9944. All of these models share behavioral and EEG similarity to human absence seizures and show pharmacologic specificity for antiabsence drugs such as ethosuximide and trimethadione. Moreover, the absence seizures induced by these agents are exacerbated by GABAergic agonists, a property unique to experimental absence seizures. These models are predictable, reproducible, and easy to standardize. They are useful both in studying mechanisms of pathogenesis of absence seizures as well as in screening for antiabsence activity of potential antiepileptic drugs.

Topics: Animals; Disease Models, Animal; Epilepsy, Absence; Isoxazoles; Penicillins; Pentylenetetrazole; Rodentia; Sodium Oxybate; trans-1,4-Bis(2-chlorobenzaminomethyl)cyclohexane Dihydrochloride

Topics: Animals; Anticonvulsants; Barbiturates; Benzodiazepines; Disease Models, Animal; Epilepsy; Etomidate; gamma-Aminobutyric Acid; Hydroxybutyrates; Isonicotinic Acids; Mice; Muscimol; Rats; Receptors, Cell Surface; Receptors, GABA-A; Sodium Oxybate

Infantile spasms (IS) is a catastrophic childhood seizure disorder that is characterized by extensor and/or flexor spasms, cognitive deterioration and a characteristic EEG abnormality. The latter consists of a pattern of a spike-wave followed by an electrodecremental response (EDR), which is a flattening of the EEG waveform amplitude. The mechanism/circuitry that underpins IS is unknown. Children with Down Syndrome (DS) are particularly vulnerable to IS. The standard mouse model of DS is the Ts65Dn mutant mouse (Ts). Using the Ts mouse, we have created an animal model of IS in DS. This model entails the treatment of Ts mice with a GABA. To address this question, we used kcnj6 triploid mice, and compared the number of spasms via video analysis and EDR events via EEG to that of the WT mice.. We now show that GABA. It is therefore likely that GIRK2 is working in concert with another factor or factors that are altered in the Ts brain in the production of the GABA

Topics: 2-Amino-5-phosphonovalerate; Animals; Anticonvulsants; Disease Models, Animal; Dose-Response Relationship, Drug; Down Syndrome; Electroencephalography; Embryo, Mammalian; G Protein-Coupled Inwardly-Rectifying Potassium Channels; Genotype; Hippocampus; Humans; In Vitro Techniques; Infant; Membrane Potentials; Mice; Mice, Inbred C57BL; Patch-Clamp Techniques; Peptide Hydrolases; Quinoxalines; Sodium Oxybate; Spasms, Infantile; Trisomy

The chronic decrease of brain amyloid-β (Aβ) peptides is an emerging therapeutic for Alzheimer's disease, but no such treatment has achieved clinical validation yet. In vivo, some brain proteases, including neprilysin, possess the ability of degrading Aβ and experimental data suggest their exploitation in strategies to reduce cerebral Aβ concentration. Previous studies have shown that pharmacologic doses of gamma-hydroxybutyrate (sodium oxybate or Xyrem) induce histone deacetylases (HDACs) inhibition and neprilysin gene expression. Here, we demonstrate that brain neprilysin overexpression induced in vivo by repeated gamma-hydroxybutyrate autoadministration reduces cerebral Aβ contents and prevents cognitive deficits in APPSWE mice. Oral gamma-hydroxybutyrate also counteracted phosphoramidon-induced brain neprilysin inhibition and Aβ accumulation. HDACs activities in SH-SY5Y cells were inhibited by gamma-hydroxybutyrate which did not affect amyloid peptide precursor intracellular domain. Together, our results suggest that gamma-hydroxybutyrate, acting via HDAC inhibition, upregulates neprilysin to reduce Aβ level and related memory deficits. Because gamma-hydroxybutyrate doses used herein are clinically relevant, our data suggest that chronic oral administration of gamma-hydroxybutyrate or its analogs may be considered for strategies against presymptomatic or established Alzheimer's disease.

Topics: Administration, Oral; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Cells, Cultured; Cognition; Disease Models, Animal; Female; Gene Expression; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Mice; Molecular Targeted Therapy; Neprilysin; Sodium Oxybate

Topics: Animals; Bridged-Ring Compounds; Disease Models, Animal; Female; Male; Mice; Sodium Oxybate; Unithiol

gamma-Hydroxybutyrate (GHB), a natural metabolite of gamma-aminobutyric acid and a drug used in humans to promote slow-wave sleep and treat narcolepsy, has been suggested to protect against ischemic stroke at high doses. This study aimed to assess recovery-promoting effects of GHB at a low dose similar to that used in patients.. Adult mice, subjected to 30 min of intraluminal middle cerebral artery occlusion, were intraperitoneally treated with GHB (100 mg/kg, twice/day, 8 h apart) or saline for 10 days. Motor recovery was evaluated by the grip strength test. The brain lesion was assessed by cresyl violet and NeuN staining 5 weeks after stroke. Expression of neuroplasticity-related genes (GAP43, c-jun, neurocan and ephrin B1) was analyzed by Taqman real-time PCR.. GHB-treated mice regained their body weight faster and recovered grip strength (3 weeks after stroke) more quickly than saline-treated mice. This was noteworthy as GHB did not influence ischemia-induced brain injury, as revealed by cresyl violet and neuronal staining. The Taqman PCR assay revealed a decreased expression of c-jun and neurocan in the ischemic striatum of GHB-treated mice in comparison to saline-treated mice.. GHB at a low dose accelerates neurological recovery following ischemic stroke. Further studies are necessary to determine the potential relationship between GHB, neuroplasticity, sleep and stroke recovery.

Topics: Adjuvants, Anesthesia; Animals; Brain Ischemia; Disease Models, Animal; Ephrin-B1; Gene Expression; Infarction, Middle Cerebral Artery; JNK Mitogen-Activated Protein Kinases; Male; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Neurocan; Neuronal Plasticity; Proteoglycans; Recovery of Function; Sodium Oxybate

Succinic semialdehyde dehydrogenase deficiency, a rare inherited defect of gamma-aminobutyrate (GABA) catabolism, presents with characteristic biochemical abnormalities in the central nervous system (CNS). These include elevated concentrations of GABA, gamma-hydroxybutyrate (GHB), succinic semialdehyde (SSA), 4,5-dihydroxyhexanoic acid (DHHA) and alanine as well as decreased concentrations of glutamine. GABA degradation is coupled to Krebs cycle function in mammalian CNS ("GABA shunt") through succinate and alpha-ketoglutarate. Accordingly, we hypothesized that disruption of Krebs cycle and respiratory chain function in the CNS is involved in the neuropathogenesis of this disease. For this purpose, we investigated cerebral activities of Krebs cycle and respiratory chain enzymes as well as the glutathione content in Aldh5a1(-/-) mice, a recently generated mouse model for this disease. In CNS tissue of Aldh5a1(-/-) mice, we found a significantly decreased glutathione content (hippocampus, cortex) and decreased activities of complexes I-IV (hippocampus) suggesting increased oxidative stress and mitochondrial dysfunction. However, specific activities of Krebs cycle and respiratory chain were not affected by GABA, GHB, SSA, or DHHA (up to 1 mmol/L). Although our results suggest hippocampal and cortical dysfunction in Aldh5a1(-/-) brain, we found no evidence that accumulating key metabolites of SSADH deficiency directly induce impairment of energy metabolism.

Topics: Animals; Brain; Brain Diseases, Metabolic, Inborn; Citric Acid Cycle; Disease Models, Animal; Electron Transport; Energy Metabolism; gamma-Aminobutyric Acid; Glutathione; Mice; Mice, Knockout; Mitochondria; Mitochondrial Diseases; Oxidative Stress; Sodium Oxybate; Subcellular Fractions; Succinate-Semialdehyde Dehydrogenase

We overview the pathophysiological bases, clinical approaches and potential therapeutic options for succinate semialdehyde dehydrogenase (SSADH; EC1.2.1.24) deficiency (gamma-hydroxybutyric aciduria, OMIM 271980, 610045) in relation to studies on SSADH gene-deleted mice, outcome data developed from 25 years of patient evaluation, and characterization of gamma-hydroxybutyric acid (GHB) pharmacology in different species. The clinical picture of this disorder encompasses a wide spectrum of neurological and psychiatric dysfunction, such as psychomotor retardation, delayed speech development, epileptic seizures and behavioural disturbances, emphasizing the multifactorial pathophysiology of SSADH deficiency. The murine SSADH-/- (e.g. Aldh5a1-/-) mouse model suffers from epileptic seizures and succumbs to early lethality. Aldh5a1-/- mice accumulate GHB and gamma-aminobutyric acid (GABA) in the central nervous system, exhibit alterations of amino acids such as glutamine (Gln), alanine (Ala) and arginine (Arg), and manifest disturbances in other systems including dopamine, neurosteroids and antioxidant status. Therapeutic concepts in patients with SSADH deficiency and preclinical therapeutic experiments are discussed in light of data collected from research in Aldh5a1-/- mice and animal studies of GHB pharmacology; these studies are the foundation for novel working approaches, including pharmacological and dietary trials, which are presented for future evaluation in this disease.

Topics: Amino Acid Metabolism, Inborn Errors; Animals; Anticonvulsants; Disease Models, Animal; gamma-Aminobutyric Acid; Humans; Mice; Mice, Knockout; Phenotype; Sodium Oxybate; Succinate-Semialdehyde Dehydrogenase

This study was performed to investigate a novel strategy to pharmacologically inhibit high-mobility group box 1 protein (HMGB1) expression with sodium butyrate, a short-chain fatty acid. Using a sepsis model induced by cecal ligation and puncture (CLP), 100 male Wistar rats were randomly divided into 4 groups as follows: control group (10 rats), sham operation group (10 rats), CLP group (further randomized into 2, 6, 12, 24, 48, and 72 h post-CLP subgroups, each 10 rats), and sodium butyrate treatment group (further randomized into 12 and 24 h post-CLP subgroups, each 10 rats). Animals of all groups were killed at designated time points, and blood and tissue samples from livers, lungs, kidneys, and small intestines were harvested to determine organ damage-related variables, and HMGB1 mRNA expression was assessed by the reverse-transcription-polymerase chain reaction. In addition, we observed the effect of treatment with sodium butyrate on survival rate in septic rats. The results showed that early treatment with sodium butyrate can markedly reduce serum alanine aminotransferase, creatinine levels at 12 h, and pulmonary myeloperoxidase activity at 24 h post-CLP, and significantly improve the 1- to 6-day survival rates in animals subjected to CLP (P < 0.05-0.01). These findings suggest that HMGB1 is excessively expressed and produced in sepsis. Sodium butyrate can markedly inhibit HMGB1 mRNA expression and may have protective effect on multiple organ damage in sepsis.

Topics: Amine Oxidase (Copper-Containing); Animals; Cecum; Disease Models, Animal; Fatty Acids; Gene Expression Regulation; High Mobility Group Proteins; HMGB1 Protein; Intestines; Male; Rats; Rats, Wistar; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; Sepsis; Sodium Oxybate; Time Factors

Riluzole, an anti-amyotrophic lateral sclerosis drug, known to decrease presynaptic glutamate release, is viewed as a candidate supplementary medication for epilepsy. In the present study, we compared the effects of riluzole and valproate (VPA) in the pilocarpine-induced limbic seizure model and in the gamma-hydroxybutyrate lactone (GBL)-induced absence seizure model. We applied immunohistochemical study for vesicular transporter 1 (VGLUT1) and extracellular recording in the rat dentate gyrus of both pilocarpine- and GBL-induced seizure models to measure effects of riluzole and VPA. Both VPA and riluzole treatments reduced VGLUT1 immunoreactivity. Riluzole treatment completely inhibited pre-ictal spikes and spike-wave discharges in the pilocarpine- and GBL-induced epilepsy models, whereas VPA partially inhibited these phenomena. In both seizure models, the anti-epileptic effects of VPA and riluzole are basically related to anti-glutamatergic (reducing field excitatory postsynaptic potential slope and excitability ratio), not GABAergic (paired-pulse inhibition) effect. Riluzole was more effective at reducing seizure activity in both epilepsy models than VPA. These results suggest that riluzole is a potential antiepileptic drug with activity against limbic seizure and absence seizure.

Topics: Animals; Anticonvulsants; Dentate Gyrus; Disease Models, Animal; Epilepsy, Absence; Excitatory Postsynaptic Potentials; Limbic System; Male; Pilocarpine; Rats; Rats, Sprague-Dawley; Riluzole; Seizures; Sodium Oxybate; Status Epilepticus; Valproic Acid; Vesicular Glutamate Transport Protein 1

Growth hormone (GH) improves wound healing and ameliorates pediatric postburn tissue catabolism associated with deficient endogenous GH/IGF-1 levels. Expense, parenteral administration, and compliance have limited widespread usage. Gammahydroxybutyrate (GHB), an upstream neuromodulatory gamma-amino butyric acid (GABA) derivative, is known to increase slow wave sleep and stimulate endogenous GH secretion. In this study, improvement in GH levels in turn has been shown to accelerate wound healing.. Body composition in male Sprague-Dawley rats with > or =40% total body surface area scald burn, receiving incremental GHB doses orally, was assessed by Dual Energy X-Ray Absorptiometry. Serum GH and IGF-1 levels were measured. Wound cross sections were scored semiquantitatively for wound healing variables.. Incremental elevation in GH and IGF-1 were associated with significantly improved wound edge epithelialization and cell-layer thickness at high doses (p < 0.005). However, body composition was similar to that of burned controls.. GHB sufficiently elevated serum GH and IGF-1 levels to significantly improve epithelialization rates and layer thickness at high doses. Substantially greater elevations of serum GH and IGF-1 levels are required in the rat burn model than for humans. GHB may improve postburn hypermetabolism in humans by elevating endogenous GH levels, though only improved epithelialization was demonstrated in this study.

Topics: Anesthetics, Intravenous; Animals; Body Composition; Bone Density; Burns; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Growth Hormone; Insulin-Like Growth Factor I; Male; Metabolic Diseases; Prospective Studies; Random Allocation; Rats; Rats, Sprague-Dawley; Sleep; Sodium Oxybate; Treatment Outcome; Wound Healing

Prior animal studies have suggested that flumazenil may blunt GHB's sedative-hypnotic affects. We hypothesized that flumazenil would decrease the affects of GHB in a murine model of intoxication.. We performed a controlled, pilot experiment using 32 mice divided into 3 groups. All mice received intraperitoneal injections of GHB (1.5 g/kg). Group I received sham injections at time 0, and then GHB at 5 minutes. Group II received flumazenil (0.3 mg/kg) at time 0, and then GHB at 5 minutes. Group III received sham injection at time 0, then GHB at 5 minutes, and then 4 escalating flumazenil doses administered at 3-minute intervals (0.003 to 1 mg/kg). We measured certain functions: time to loss/recovery of righting reflexes (RR), time to sprawl/recovery of sprawl (postural tone [PT]), and death.. There were statistically significant delays in the loss of PT and shortened recovery time to RR in pre-treated mice (group II) versus controls (group I). There were no differences in group III versus group I for any outcome parameters.. In this model, pre-dosing flumazenil prior to GHB administration delayed clinical intoxication.

Topics: Animals; Antidotes; Behavior, Animal; Disease Models, Animal; Flumazenil; Mice; Pilot Projects; Poisoning; Posture; Reflex; Research Design; Sodium Oxybate; Time Factors

Physostigmine is an acetylcholinesterase inhibitor and can produce fasciculations, seizures, bradycardia, and asystole. gamma-hydroxybutyrate (GHB) increases acetylcholine levels in the central nervous system and can decrease heart rate. Despite this, physostigmine has been proposed as an arousal agent to treat coma from overdoses of GHB. The authors hypothesized that in the setting of severe GHB intoxication, physostigmine would reverse sedation without producing adverse effects such as a decrease in heart rate, seizures, and fasciculations.. GHB intoxication was induced in 20 rats by intraperitoneal injection of 700 mg/kg of the GHB precursor gamma-butyrolactone. One hour later, rats were randomly assigned to receive either physostigmine (0.06 mg/kg) intraperitoneally or an equivalent volume of saline. After administration of physostigmine, rats were continuously monitored by a blinded observer for arousal (return of righting reflex), fasciculations, and seizures. Heart rate and respiratory rate were recorded at 0, 5, 15, and 60 minutes after administration of physostigmine. Data were analyzed using repeated-measures analysis of variance and chi-square test. A pretest sample size calculation determined that 10 rats per group would detect a change in arousal from 0% to 50% and a 10% change in heart rate.. No rats in either group had arousal within one hour (p = 1.0); however, ten of ten physostigmine-treated rats developed signs of physostigmine toxicity (fasciculations, 7; seizures, 3), while no controls developed signs of physostigmine toxicity (p = 0.00). The authors were unable to detect a decrease in heart rate.. Physostigmine did not produce a 50% change in arousal as measured by a return of righting reflex but did produce physostigmine toxicity (fasciculations and seizures) in this rat model of severe GHB intoxication.

Topics: Animals; Arousal; Cholinesterase Inhibitors; Coma; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Overdose; Fasciculation; Heart Rate; Male; Physostigmine; Random Allocation; Rats; Rats, Sprague-Dawley; Reflex; Respiratory Mechanics; Seizures; Sodium Oxybate

This study aims to evaluate the effects of gamma-hydroxybutyrate (GHB) after spinal cord trauma (SCT). Twenty rabbits were divided equally into four groups: group I was the sham-operated group, group II suffered from SCT but received no treatment, group III was given a dose of 400 mg/kg of GHB intravenously before SCT and group IV received the same dose after SCT. Cerebrospinal fluid (CSF) samples were obtained 30 min before SCT (T(0)), at 60 (T(1)) and 120 min (T(2)) after SCT. There was a threefold increase in lactate levels from baseline value at T(2) in group II, while statistically significant elevation of the lactate levels were not observed in groups III and IV. Glucose levels at T(1) and T(2) were significantly lower in groups III and IV compared with the control group. The findings of this study demonstrate that GHB can control the increase of CSF lactate and glucose levels following SCT and that this metabolic effect may be associated with neuroprotective physiological changes.

Topics: Adjuvants, Anesthesia; Analysis of Variance; Animals; Blood Pressure; Disease Models, Animal; Glucose; Heart Rate; Lactic Acid; Lipid Peroxidation; Male; Rabbits; Sodium Oxybate; Spinal Cord Injuries; Time Factors

Gamma-hydroxybutyrate (GHB) and its lactone, gamma-butyrolactone (GBL) have been previously shown to produce a protective effect in animal models of cerebral ischaemia/hypoxia, as well as in human conditions of head injury-induced coma. The aim of the present research was to study the effect of GHB in experimental conditions of focal cerebral damage, either induced by ischaemia or excitotoxicity. Under general anaesthesia, rats were injected into the right striatum with either endothelin-1 (ET-1, 0.43 nmol) or kainic acid (7.5 nmol) in a volume of 1 microl. Sham-lesioned rats received 1 microl of the solvent. Both ET-1- and kainic acid-lesioned rats were randomly assigned to one of the following intraperitoneal (i.p.) treatments: (i) and (ii) GHB, 100 or 300 mg kg(-1) 2 h after the lesion, followed by 50 or 100 mg kg(-1), respectively, every 12 h; (iii) saline, 2 ml kg(-1), same schedule. Sham animals were treated with saline, 2 ml kg(-1), same schedule. Treatments lasted for 10 days. The higher dose of GHB produced a significant protection against the ET-1-induced impairments in sensory-motor orientation and coordinated limb use (evaluated 24 and 42 days after the lesion) and in place learning and memory (Morris test, performed 19 and 39 days after the lesion). The same dose regimen reduced the circling behaviour induced by apomorphine in kainate-lesioned rats (10 days after the lesion), and limited or prevented at all the histological damage produced either by ET-1 or by kainic acid (evaluated 43 or 10 days after the lesion, respectively). These results show that GHB limits both histological and functional consequences of a focal ischaemic or excitotoxic insult of the brain, in rats, even if the treatment is started 2 h after the lesion.

Topics: Animals; Apomorphine; Brain; Brain Ischemia; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelin-1; Kainic Acid; Learning; Male; Memory Disorders; Motor Activity; Nerve Degeneration; Neuroprotective Agents; Neurotoxins; Rats; Rats, Wistar; Sodium Oxybate

Topics: Aldehyde Oxidoreductases; Animals; Disease Models, Animal; gamma-Aminobutyric Acid; Mice; Sodium Oxybate; Succinate-Semialdehyde Dehydrogenase

Metabolite profiling in succinate semialdehyde dehydrogenase (SSADH; Aldh5a1-/-) deficient mice previously revealed elevated gamma-hydroxybutyrate (GHB) and total GABA in urine and total brain and liver extracts. In this study, we extend our metabolic characterization of these mutant mice by documenting elevated GHB and total GABA in homogenates of mutant kidney, pancreas and heart. We quantified beta-alanine (a GABA homolog and putative neurotransmitter) to address its potential role in pathophysiology. We found normal levels of beta-alanine in urine and total homogenates of mutant brain, heart and pancreas, but elevated concentrations in mutant kidney and liver extracts. Amino acid analysis in mutant total brain homogenates revealed no abnormalities except for significantly decreased glutamine, which was normal in mutant liver and kidney extracts. Regional amino acid analysis (frontal cortex, parietal cortex, hippocampus and cerebellum) in mutant mice confirmed glutamine results. Glutamine synthetase protein and mRNA levels in homogenates of mutant mouse brain were normal. We profiled organic acid patterns in mutant brain homogenates to assess brain oxidative metabolism and found normal concentrations of Kreb's cycle intermediates but increased 4,5-dihydroxyhexanoic acid (a postulated derivative of succinic semialdehyde) levels. We conclude that SSADH-deficient mice represent a valid metabolic model of human SSADH deficiency, manifesting focal neurometabolic abnormalities which could provide key insights into pathophysiologic mechanisms.

Topics: Aldehyde Oxidoreductases; Animals; beta-Alanine; Blotting, Western; Brain; Carboxylic Acids; Disease Models, Animal; Female; gamma-Aminobutyric Acid; Glutamate-Ammonia Ligase; Glutamine; Kidney; Liver; Male; Mice; Mice, Knockout; Myocardium; Organ Specificity; Oxidation-Reduction; Pancreas; RNA, Messenger; Sodium Oxybate; Succinate-Semialdehyde Dehydrogenase

Sodium valproate(VPA), ethosuximide(ESM), 200 mg/kg ip and flunarizine (FLU) 5 or 10 mg/kg ip were first administered independently to rats in order to study their effects on behavioural and EEG aspects of spike and wave discharges (SWDs) induced by y- hydroxybutyrate (GHB,100 mg/kg ip). GHB treated rats show behavioural changes and concomitant repetitive EEG episodes of 7 to 9 Hz SWDs, mimicking human absence seizures (AS), and can be used as a pharmacological model. The number and duration of SWDs were calculated for 1 hr from the EEG and were parameters for drug evaluation. VPA and ESM at 200 mg/kg, significantly reduced SWD number and duration/hr, while FLU showed significant reduction only at 10 but not at 5 mg/kg. Combination of FLU, 10 mg/kg with either VPA or ESM showed significant reduction of SWD number and duration, suggesting an additive effect of the anti-absence agents with the calcium channel blocker, FLU, on experimental absence seizures in rats.

Topics: Animals; Anticonvulsants; Calcium Channel Blockers; Disease Models, Animal; Drug Interactions; Drug Synergism; Electroencephalography; Epilepsy, Absence; Ethosuximide; Flunarizine; Male; Rats; Rats, Wistar; Sodium Oxybate; Valproic Acid

Sodium valproate (VPA) and ethosuximide (ESM) were compared on behavioural and EEG changes in gamma-hydroxybutyrate (GHB) and pentylenetetrazole (PTZ) rat models of Absence Seizures (AS). Both GHB, 100 mg/kg i.p. and PTZ, 20 mg/kg i.p., produced repetitive episodes of staring and immobility with concomitant 6 to 9 Hz spike and wave discharges (SWDs) in the EEG. The parameters used for drug evaluation were the number and duration of SWDs/hour. Though the number of SWDs/hour produced by GHB and PTZ were not significantly different, the duration of SWDs was significantly longer in GHB treated rats (P < 0.001) VPA and ESM, at 200 mg/kg i.p., reduced SWD number and duration in GHB pretreated rats, whereas ESM, 50 mg/kg i.p., was four times more effective than VPA, 200 mg/kg i.p., in the PTZ model. Phenytoin (PHY) 20 and Carbamazepine (CBZ) 10 mg/kg i.p., worsened AS, a feature which has also been reported clinically. Both rat models of experimental AS can be used to defect potential anti-absence activity in new chemical entities.

Topics: Animals; Anticonvulsants; Convulsants; Disease Models, Animal; Electroencephalography; Epilepsy, Absence; Ethosuximide; Male; Pentylenetetrazole; Rats; Rats, Wistar; Sodium Oxybate; Species Specificity; Valproic Acid

We examined the pharmacological profiles of generalized absence seizures in three mouse models: two mutant strains with spontaneous absence seizures, lethargic and stargazer, and ddY mice (GHB model) in which absence seizures were induced by administering gamma-butyrolactone (GBL), a prodrug of gamma-hydroxybutyric acid (GHB). A typical antiabsence drug, ethosuximide (200 mg/kg), attenuated absence seizure behavior, spike and wave and paroxysmal discharges (SWDs and PDs) in each model. P-[3-Aminopropyl]-P-diethoxymethylphosphinic acid (CGP 35348), a selective gamma-aminobutyric acid (GABA)B antagonist (200 mg/kg), suppressed absence seizure behavior, SWDs and PDs at least as effectively as ethosuximide (200 mg/kg) in lethargic and GHB model mice. P-[3-Aminopropyl]-P-cyclohexylmethylphosphinic acid (CGP 46381) was more effective than CGP 35348 and ethosuximide in these models. Although the antiabsence effect of CGP 46381 was as strong as that of ethosuximide (200 mg/kg) in stargazer mice, CGP 35348 (200-400 mg/kg) was weaker than ethosuximide. (+)-5-Methyl-10,11-dihydro-5H-dibenzo[a,b]cyclohepten-5,10-imine hydrogen maleate (MK-801), a non-competitive N-methyl-D-aspartate (NMDA) antagonist (0.5 mg/kg), had no effects on SWDs and PDs in lethargic or GHB model mice. Although MK-801 (0.5 mg/kg) suppressed SWDs significantly in stargazer mice, irregular electroencephalographic patterns were observed. These results suggest that GABAB receptors play a significant role in the pathogenesis of generalized absence seizures in these models, although the mechanism involved in stargazer mice differ from that in the other two.

Topics: Animals; Disease Models, Animal; Dizocilpine Maleate; Electroencephalography; Epilepsy, Generalized; Female; GABA Antagonists; Male; Mice; Mice, Neurologic Mutants; Organophosphorus Compounds; Phosphinic Acids; Sodium Oxybate

Recent studies have shown that gamma-aminobutyric acidB (GABAB) receptor antagonists suppress absence seizures in animal models. (+)-5,5-Dimethyl-2-morpholineacetic acid, hydrochloride (SCH 50911) is a new GABAB antagonist that is structurally dissimilar to previously studied GABAB antagonists such as 3-aminopropyl-diethoxymethyl-phosphinic acid (CGP 35348), 3-aminopropyl-n-butyl-phosphinic acid (CGP 36742) or 3-aminopropyl-cyclohexylmethyl-phosphinic acid (CGP 46381). In this study we measured the antiabsence effects of SCH 50911 in three animal models: the lethargic (lh/lh) mutant mouse, which has spontaneous absence seizures; and two rat models in which absence seizures were induced by administration of either gamma-hydroxybutyrate or pentylenetetrazole. SCH 50911 abolished seizures in all three models in a dose-dependent fashion (ID100 = 8-170 mumol/kg). In each model SCH 50911 was more potent (ID50 = 2-22 mumol/kg) than the following antiabsence compounds: the GABAB antagonist CGP 35348 (ID50 = 210-890 mumol/kg); ethosuximide (ID50 < or = 142-1240 mumol/kg); trimethadione (ID50 = 520-1100 mumol/kg); and valproic acid (ID50 = 900-2360 mumol/kg). SCH 50911 was equipotent with the GABAB antagonist CGP 46381 (ID50 = 20 mumol/kg) in the lh/lh mouse model. These findings suggest that antiabsence activity may be a defining feature of GABAB receptor antagonists and provide a rationale for pursuing clinical trials of GABAB receptor antagonists in human patients with absence seizures.

Topics: Animals; Anticonvulsants; Behavior, Animal; Disease Models, Animal; Electroencephalography; Epilepsy, Absence; GABA Antagonists; Humans; Male; Mice; Mice, Mutant Strains; Morpholines; Pentylenetetrazole; Rats; Sodium Oxybate

We have investigated whether the pathogenesis of spontaneous generalized non-convulsive seizures in rats with genetic absence epilepsy is due to an increase in the brain levels of gamma-hydroxybutyric acid (GHB) or in the rate of its synthesis. Concentrations of GHB or of its precursor gamma-butyrolactone (GBL) were measured with a new GC/MS technique which allows the simultaneous assessment of GHB and GBL. The rate of GHB synthesis was estimated from the increase in GHB levels after inhibition of its catabolism with valproate. The results of this study do not indicate significant differences in GHB or GBL levels, or in their rates of synthesis in rats showing spike-and-wave discharges (SWD) as compared to rats without SWD. Binding data indicate that GHB, but not GBL, has a selective, although weak affinity for GABAB receptors (IC50 = 150 microM). Similar IC50 values were observed in membranes prepared from rats showing SWD and from control rats. The average GHB brain levels of 2.12 +/- 0.23 nmol/g measured in the cortex and of 4.28 +/- 0.90 nmol/g in the thalamus are much lower than the concentrations necessary to occupy a major part of the GABAB receptors. It is unlikely that local accumulations of GHB reach concentrations 30-70-fold higher than the average brain levels. After injection of 3.5 mmol/kg GBL, a dose sufficient to induce SWD, brain concentrations reach 240 +/- 31 nmol/g (Snead, 1991) and GHB could thus stimulate the GABAB receptor. Like the selective and potent GABAB receptor agonist R(-)-baclofen, GHB causes a dose-related decrease in cerebellar cGMP. This decrease and the increase in SWD caused by R(-)-baclofen were completely blocked by the selective and potent GABAB receptor antagonist CGP 35348, whereas only the increase in the duration of SWD induced by GHB was totally antagonized by CGP 35348. The decrease in cerebellar cGMP levels elicited by GHB was only partially antagonized by CGP 35348. These findings suggest that all effects of R(-)-baclofen are mediated by the GABAB receptor, whereas only the induction of SWD by GHB is dependent on GABAB receptor mediation, the decrease in cGMP being only partially so. Taken together with the observations of Marescaux et al. (1992), these results indicate that GABAB receptors are of primary importance in experimental absence epilepsy and that GABAB receptor antagonists may represent a new class of anti-absence drugs.

Topics: 4-Butyrolactone; Animals; Baclofen; Brain; Cyclic GMP; Disease Models, Animal; Epilepsy, Absence; GABA-A Receptor Antagonists; Male; Organophosphorus Compounds; Rats; Rats, Inbred Strains; Receptors, GABA-A; Reference Values; Reproducibility of Results; Sodium Oxybate; Valproic Acid

We have previously shown that gamma-hydroxybutyrate (GHB) protects the small intestine against ischemia/reperfusion injury. This study examined the effects of GHB on cardiovascular function and intestinal microcirculation following hemorrhage. Hypotension was induced in control group of hamsters by controlled hemorrhage to a mean arterial pressure (MAP) of 40 mm Hg. Following 60 minutes of hypovolemia the shed blood was returned. This procedure resulted in complete intestinal mucosal microvascular stasis 2 hours following the return of shed blood. A second group of animals was treated with GHB (600 mg/kg body weight) and, despite the loss of 37% of total blood volume, GHB treatment completely prevented the microcirculatory stasis, following the reinfusion of shed blood. In male Wistar rats treated with GHB (200 mg/kg) after the induction of hemorrhage, blood pressure rapidly increased to pre-hemorrhage levels following treatment, even though the shed blood was not returned. Cardiac output (CO) also increased to pre-hemorrhage levels. Sodium chloride solution, in the same molar concentration as GHB (23% NaCl), produced much smaller, but statistically significant, increases in MAP and CO. In animals given an equal volume of normal saline, a gradual increase in MAP was observed, reaching statistical significance at 75 minutes following treatment. Three hours following hemorrhage, serum levels of creatine kinase were 3-fold higher, whereas aspartate aminotransaminase and alanine aminotransferase levels were 2-fold higher in both normal saline and hypertonic saline-treated animals than in GHB-treated animals. These experiments suggest that GHB can prevent ischemic complications following a hypovolemic episode and may improve survival following severe hemorrhage.

Topics: Animals; Cricetinae; Disease Models, Animal; Hemodynamics; Hypertonic Solutions; Intestines; Ischemia; Male; Mesocricetus; Microcirculation; Shock, Hemorrhagic; Sodium Chloride; Sodium Oxybate; Splanchnic Circulation

The oxybuturate sodium influence on the vessel and cells dynamics in the source of aseptic inflammation was studied. It was shown that oxybuturate sodium injection (100 mg/kg) before 30 min and after 2 and 4 hours of inflammation onset leads to suppression of microvessel reaction, reduction of macrophagic infiltrate density, decrease of macrophagic phase duration and the earliest perfection of inflammation in the whole.

Topics: Animals; Disease Models, Animal; Drug Evaluation, Preclinical; Inflammation; Microcirculation; Rats; Sodium Oxybate; Time Factors

The effect of the unsaturated lactone, gamma-crotonolactone (GCL), against spike wave discharges (SWD) in two pharmacological models of generalized absence seizures in rat was investigated. The models used were the gamma-hydroxybutyrate (GHB) model and the low dose pentylenetetrazole model. GCL pretreatment resulted in a significant decrease in duration of SWD in both models. In addition, this compound reduced the ability of the agonist, muscimol, to enhance SWD duration in the GHB model and was effective in developing animals as well as in adult animals with GHB-induced SWD. These data suggest that GCL may be a useful tool in the study of basic mechanisms of SWD generation in experimental absence seizures.

Topics: 4-Butyrolactone; Animals; Anticonvulsants; Disease Models, Animal; Electroencephalography; Furans; Male; Pentylenetetrazole; Rats; Rats, Inbred Strains; Seizures; Sodium Oxybate; Time Factors

The antihypoxic effects of gutimine, piracetam, sodium hydroxybutyrate and lithium hydroxybityrate were studied on different models of brain hypoxia. All the drugs under study produced a remarkable antihypoxic effect in experimental asphyxic hypoxia, increasing brain resistance to oxygen deficiency and rapidly restituting brain function. Drug pretreatment of the animals with carotid artery occlusion raised the number of animals which survived 24 h after the operation. GABA salts appeared the most effective. Sodium hydroxybutyrate increased the lifespan of rats under histotoxic hypoxia.

Topics: Animals; Asphyxia; Brain Ischemia; Disease Models, Animal; Drug Evaluation, Preclinical; Electrocardiography; Electroencephalography; Guanylthiourea; Hydroxybutyrates; Hypoxia, Brain; Lithium; Male; Organometallic Compounds; Piracetam; Rats; Sodium Nitrite; Sodium Oxybate

Topics: Animals; Disease Models, Animal; Humans; Hydroxybutyrates; Mice; Myoclonus; Sodium Oxybate

The cerebral protection afforded by each of several preparations of gamma-hydroxybutyrate (GHB) was examined in the hypoxic (FiO2 = 0.05) mouse model. The greatest increase in survival time (85%) occurred after pretreatment with 300 mg/kg given as buffered gamma-butyrolactone (GBL). Compared with previous studies employing the same hypoxic model, this increase was less than that observed with certain barbiturates and equal to that observed with certain anesthetics. The cerebral and systemic metabolic and vascular effects of each of several preparations of GHB were examined in a canine model. The cerebral metabolic rate for oxygen (CMRO2) tended to increase after GHB 100 mg/kg, then progressively decreased after cumulative doses of 600 mg/kg and 1100 mg/kg. The greatest depression in CMRO2 (48%) occurred with 1100 mg/kg given as unbuffered GBL. With each preparation and at every dose, a reduction in cerebral blood flow (CBF) exceeded the reduction in CMRO2. The major systemic effect was an almost two-thirds reduction in cardiac output at the largest doses. Assuming no species difference the cerebral protection observed with GHB is probably limited by both the reduction in cardiac output and the unfavorable relationship of cerebral oxygen supply to demand (CBF/CMRO2). Brain biopsies taken after the cumulative dose of GHB 1100 mg/kg showed a trend toward lower phosphocreatine levels and higher lactate and lactate/pyruvate levels than in untreated dogs.

Topics: 4-Butyrolactone; Animals; Brain; Cerebrovascular Circulation; Disease Models, Animal; Dogs; Furans; Hydroxybutyrates; Hypoxia; Male; Mice; Oxygen; Sodium Oxybate