naloxone and Reperfusion-Injury

The aim of this study was to assess the effects of naloxone, an opioid receptor antagonist, on the renal injury as a remote organ after hepatic ischemia reperfusion (IR) in rats.. Forty male Wistar rats were randomly allocated into four groups as follows: sham, sham + naloxone, IR and IR + naloxone. In anesthetized rats, hepatic ischemia was applied for 30 min in IR and IR + naloxone groups. Sham + naloxone and IR + naloxone groups were given naloxone (3.0 mg/kg, iv) 30 min before ischemia. After 24 h, blood and tissue samples were obtained for histopathological, tissue malondialdehyde (MDA) and biochemical analyses.. Histopathological study of liver in IR group showed enlarged sinusoids, sinusoidal congestion, cellular degenerative changes and necrosis. The kidney of the rats with hepatic IR showed pathological changes in tubular cell swelling, tubular dilatation, moderate to severe necrosis, glomerular fibrosis and hemorrhage. Histological examination confirmed the extent of hepatic and renal changes in IR group was higher (P < 0.05) than in other groups. Rats that underwent hepatic IR exhibited significant increase in serum concentrations of urea and creatinine levels (P < 0.05). The serum alanine aminotransferase and aminotransferase values were significantly higher in IR group compared to the other groups (P < 0.05). Liver IR produced a significant increase in hepatic and renal tissue MDA levels, while pretreatment with naloxone was associated with a significantly lower MDA levels (P < 0.05).. The results of this study showed that naloxone pretreatment protected the renal injury from hepatic IR.

Topics: Acute Kidney Injury; Animals; Biopsy, Needle; Disease Models, Animal; Immunohistochemistry; Ischemic Preconditioning; Liver; Male; Naloxone; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury; Sensitivity and Specificity

Hepatic injury induced by ischemia-reperfusion (I/R) after transplantation or lobectomy is a major clinical problem. The potential benefit of remifentanil in these hepatic surgeries remains unknown. The current study investigated whether remifentanil protects the liver against I/R injury in a rat model and whether the underlying mechanism involves the modulation of interleukin (IL)-18 signaling.. Male Sprague-Dawley rats were subjected to 45 minutes of partial hepatic ischemia followed by 6 hours of reperfusion. Then, they received an intravenous saline or remifentanil (0.4, 2, or 10 μg/kg per minute) infusion from 30 minutes before ischemia until the end of ischemia with or without previous administration of naloxone, a nonselective opioid receptor antagonist. Serum aminotransferase, hepatic morphology, and hepatic neutrophil infiltration were analyzed. The expression of hepatic IL-18; IL-18-binding protein (BP); and key cytokines downstream of IL-18 signaling were measured.. Remifentanil significantly decreased serum aminotransferase levels and profoundly attenuated the liver histologic damages. Liver I/R injury increased the expression of both hepatic IL-18 and IL-18BP. Although remifentanil pretreatment significantly decreased I/R-induced IL-18 expression, it further upregulated IL-18BP levels in liver tissues. The I/R-induced increases of hepatic interferon-γ, tumor necrosis factor-α and IL-1β expression, and neutrophil infiltration were also significantly reduced by remifentanil. Naloxone inhibited the remifentanil-induced downregulation of IL-18, but not the elevation of IL-18BP, and significantly attenuated its protective effects on liver I/R injury.. Remifentanil protects the liver against I/R injury. Modulating the hepatic IL-18/IL-18BP balance and inhibiting IL-18 signaling mediate, at least in part, the hepatoprotective effects of remifentanil.

Topics: Analgesics, Opioid; Animals; Gene Expression Regulation; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Interferon-gamma; Interleukin-18; Ischemia; Liver; Male; Naloxone; Neutrophils; Peroxidase; Piperidines; Rats; Rats, Sprague-Dawley; Remifentanil; Reperfusion Injury; Signal Transduction; Transaminases

Ischemia-reperfusion of bone occurs in a variety of clinical conditions, such as orthopedic arthroplasty, plastic gnathoplasty, spinal surgery, and amputation. Usually, cellular models of hypoxia-reoxygenation reflect in vivo models of ischemia-reperfusion. With respect to hypoxia-reoxygenation conditions, the effects of remifentanil on osteogenesis have received little attention. Therefore, we investigated the effects of remifentanil on the proliferation and differentiation of osteoblasts during hypoxic-reoxygenation.. After remifentanil (0.1, 1 ng/mL) preconditioning for 2 hours, human osteoblasts were cultured under 1% oxygen tension for 24 hours. Thereafter, the cells were reoxygenated for 12 hours at 37 °C. The naloxone groups were treated with naloxone for 30 minutes before remifentanil treatment. We measured cell viability via MTT assay. Osteoblast maturation was determined by assay of bone nodular mineralization. Quantitative PCR and western blot methods were used to determine BMP-2, osteocalcin, Akt, type I collagen, osterix, TGF-β1, HIF-1α, and RUNX2 expression levels.. Osteoblast viability and bone nodular mineralization by osteoblasts is recovered by remifentanil preconditioning from hypoxia-reoxygenation insult. During hypoxic-reoxygenation condition, remifentanil preconditioning induced the expression of BMP-2, osteocalcin, Akt, type I collagen, osterix, TGF-β1, HIF-1α, and RUNX2 in osteoblasts.. Under hypoxia-reoxygenation conditions, remifentanil preconditioning enhanced the cell viability and maturation of osteoblasts, and stimulated the expression of proteins associated with osteoblast proliferation and differentiation of the osteoblast. Our results suggest that remifentanil may help in the treatment of bone stress injuries.

Topics: Bone and Bones; Cell Hypoxia; Cell Proliferation; Cell Survival; Gene Expression Regulation; Humans; Naloxone; Osteoblasts; Osteogenesis; Oxygen; Piperidines; Remifentanil; Reperfusion Injury

Renal ischemia produces sympathoexcitation, which is responsible for the development of ischemic acute kidney injury. Stimulation of central opioid receptors activates the renal sympathetic nerve. The present study examined the effect of an opioid receptor antagonist naloxone on the ischemia/reperfusion-induced renal dysfunction in mice. Blood urea nitrogen (BUN) and plasma creatinine increased 24 h after the renal ischemia/reperfusion. Intraperitoneal or intracerebroventricular, but not intrathecal, pretreatment with naloxone suppressed the renal ischemia/reperfusion-induced increases in BUN and plasma creatinine. This effect of naloxone was reversed by subcutaneous pretreatment with morphine. Selective MOP receptor antagonist β-funaltrexamine (FNA) also suppressed the renal ischemia/reperfusion-induced increases in BUN and plasma creatinine. Moreover, tyrosine hydroxylase expression in the renal tissue increased 24 h after renal ischemia/reperfusion, which was abolished by intraperitoneal or intracerebroventricular pretreatment with naloxone and FNA. Immunohistochemical experiments revealed a significant increase in the number of the Fos family proteins (c-Fos, FosB, Fra-1, and Fra-2) positive cells in the paraventricular nucleus of hypothalamus and supraoptic nucleus 24 h after the renal ischemia/reperfusion. Intracerebroventricular pretreatment with naloxone attenuated the renal ischemia/reperfusion-induced increase in the number of the Fos family proteins positive cells in these areas. Finally, we observed that i.c.v. pretreatment with antiserum against β-endorphin also suppressed the increased blood urea and plasma creatinine. These results suggest that the blockade of central opioid receptors can attenuate the ischemic acute kidney injury through the inhibition of renal sympathoexcitation. The central opioid receptors may thus be a new target for the treatment of ischemic organ failures.

Topics: Analgesics, Opioid; Animals; Dose-Response Relationship, Drug; Hypothalamus, Anterior; Injections, Intraperitoneal; Injections, Intraventricular; Kidney; Male; Mice; Mice, Inbred ICR; Molecular Targeted Therapy; Naloxone; Naltrexone; Narcotic Antagonists; Nerve Tissue Proteins; Neurons; Proto-Oncogene Proteins c-fos; Receptors, Opioid, mu; Renal Insufficiency; Reperfusion Injury

Ischemia-reperfusion injury plays an important role in the development of primary allograft failure after heart transplantation. Inhibition of the Na+/H+ exchanger is one of the most promising therapeutic strategies for treating ischemia-reperfusion injury. Here we have characterized the cardioprotective efficacy of zoniporide and the underlying mechanisms in a model of myocardial preservation using rat isolated working hearts.. Rat isolated hearts subjected to 6 h hypothermic (1-4°C) storage followed by 45 min reperfusion at 37°C were treated with zoniporide at different concentrations and timing. Recovery of cardiac function, levels of total and phosphorylated protein kinase B, extracellular signal-regulated kinase 1/2, glycogen synthase kinase-3β and STAT3 as well as cleaved caspase 3 were measured at the end of reperfusion. Lactate dehydrogenase release into coronary effluent before and post-storage was also measured.. Zoniporide concentration-dependently improved recovery of cardiac function after reperfusion. The functional recovery induced by zoniporide was accompanied by up-regulation of p-extracellular signal-regulated kinase 1/2 and p-STAT3, and by reduction in lactate dehydrogenase release and cleaved caspase 3. There were no significant differences in any of the above indices when zoniporide was administered before, during or after ischemia. The STAT3 inhibitor, stattic, abolished zoniporide-induced improvements in functional recovery and up-regulation of p-STAT3 after reperfusion.. Zoniporide is a potent cardioprotective agent and activation of STAT3 plays a critical role in the cardioprotective action of zoniporide. This agent shows promise as a supplement to storage solutions to improve preservation of donor hearts.

Topics: Animals; Cardiotonic Agents; Cardiovascular Physiological Phenomena; Caspase 3; Cyclic S-Oxides; Disease Models, Animal; Dose-Response Relationship, Drug; Guanidines; Heart; Heart Transplantation; L-Lactate Dehydrogenase; Male; Mitogen-Activated Protein Kinase 3; Myocardium; Naloxone; Narcotic Antagonists; Pyrazoles; Rats; Rats, Wistar; Reperfusion Injury; STAT3 Transcription Factor

The detrimental role of TNF-α in ischemia-induced tissue damage is known. The authors study examined whether opioid receptor activation alters TNF-α levels in the postischemic retina.. Retinal ischemia was induced by raising the intraocular pressure above systolic blood pressure (155-160 mm Hg) for 45 minutes. Rats were pretreated with the opioid receptor agonist morphine (1 mg/kg; intraperitoneally) before injury. Selected animals were pretreated with the opioid antagonist naloxone (3 mg/kg; intraperitoneally). Human optic nerve head (ONH) astrocytes and rat microglial cells were treated with morphine (0.1-1 μM) for 24 hours and then treated with 10 μg/mL or 30 ng/mL lipopolysaccharide (LPS), respectively. TNF-α was measured by ELISA. Opioid receptor subtypes in astrocytes and microglia were determined by Western blot analysis.. There was a time-dependent increase in TNF-α production; the maximum production occurred at 4 hours after ischemia and localized to the inner retinal regions. Ischemia-induced TNF-α production was significantly inhibited by morphine. In astrocytes and microglia, LPS triggered a robust increase in the release of TNF-α, which was significantly inhibited (P < 0.05) by morphine. Naloxone reversed the morphine-induced suppression of TNF-α production in vivo and in vitro. Both ONH astrocytes and microglial cells expressed δ-, κ-, and μ-opioid receptor subtypes.. These data provide evidence that the production of TNF-α after ischemia/reperfusion injury is an early event and that opioid receptor activation reduces the production of TNF-α. Immunohistochemistry data and in vitro studies provide evidence that ONH astrocytes and microglial cells are the primary sources for the TNF-α production under ischemic/inflammatory conditions. Activation of one or more opioid receptors can reduce ischemic/reperfusion injury by the suppression of TNF-α production.

Topics: Animals; Astrocytes; Blotting, Western; Cells, Cultured; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique, Indirect; Lipopolysaccharides; Male; Microglia; Morphine; Naloxone; Narcotic Antagonists; Optic Disk; Rats; Rats, Inbred BN; Receptors, Opioid; Reperfusion Injury; Retina; Retinal Diseases; Time Factors; Tumor Necrosis Factor-alpha

The purpose of this study is to determine 1) whether morphine post condition (MPostC) can attenuate the intercellular adhesion molecules-1 (ICAM-1) expression after reoxygenation injury and 2) the subtype(s) of the opioid receptors (ORs) that are involved with MPostC. Human umbilical vein endothelial cells (HUVECs) were subjected to 6 hr anoxia followed by 12 hr reoxygenation. Three morphine concentrations (0.3, 3, 30 µM) were used to evaluate the protective effect of MPostC. We also investigated blockading the OR subtypes' effects on MPostC by using three antagonists (a µ-OR antagonist naloxone, a κ-OR antagonist nor-binaltorphimine, and a δ-OR antagonist naltrindole) and the inhibitor of protein kinase C (PKC) chelerythrine. As results, the ICAM-1 expression was significantly reduced in the MPostC (3, 30 µM) groups compared to the control group at 1, 6, 9, and 12 hours reoxygenation time. As a consequence, neutrophil adhesion was also decreased after MPostC. These effects were abolished by co administering chelerythrine, nor-binaltorphimine or naltrindole, but not with naloxone. In conclusion, it is assumed that MPostC could attenuate the expression of ICAM-1 on endothelial cells during reoxygenation via the κ and δ-OR (opioid receptor)-specific pathway, and this also involves a PKC-dependent pathway.

Topics: Animals; Benzophenanthridines; Endothelial Cells; Endothelium, Vascular; Humans; Intercellular Adhesion Molecule-1; Morphine; Naloxone; Naltrexone; Narcotic Antagonists; Narcotics; Protein Isoforms; Protein Kinase C; Receptors, Opioid; Reperfusion Injury; Signal Transduction; Umbilical Veins

Opioid preconditioning against ischemia reperfusion injury has been well studied in myocardial and neuronal tissues. The objective of this study was to determine whether remifentanil could attenuate hepatic injury and to investigate the mechanisms.. A rat model of hepatic ischemia reperfusion injury and a hepatocyte hypoxia reoxygenation (HR) injury model were used, respectively, in two series of experiments. Remifentanil was administered before ischemia or hypoxia and the experiments were repeated with previous administration of naloxone, L-arginine and N-ω-nitro-L-arginine methyl ester, a nonselective opioid receptor antagonist, a nitric oxide donor, and nitric oxide synthase (NOS) inhibitor, respectively. Serum aminotransferase, cytokines, and hepatic lipid peroxidation were measured. Histopathology examination and apoptotic cell detection were assessed. For the in vitro study, cell viability, intracellular nitric oxide, apoptosis, and NOS expression were evaluated.. Remifentanil and L-arginine pretreatment reduced concentrations of serum aminotransferases and cytokines, decreased the concentrations of hepatic malondialdehyde and myeloperoxidase activity, and increased superoxide dismutase, nitric oxide, and inducible NOS expression in vivo. Decreased histologic damage and apoptosis were also seen in these two groups. These changes were prevented by previous administration of N-ω-nitro-L-arginine methyl ester but not naloxone. There was an increase in inducible NOS protein expression but not endogenous NOS in remifentanil and L-arginine pretreated groups compared with control, naloxone, and N-ω-nitro-L-arginine methyl ester groups.. Pretreatment with remifentanil can attenuate liver injury both in vivo and in vitro. Inducible NOS but not opioid receptors partly mediate this effect by exhausting reactive oxygen species and attenuating the inflammatory response.

Topics: Analgesics, Opioid; Animals; Arginine; Blotting, Western; Cell Survival; Cytokines; Disease Models, Animal; Ischemic Preconditioning; Lipid Peroxidation; Liver; Liver Diseases; Male; Naloxone; Narcotic Antagonists; Nitric Oxide Synthase; Piperidines; Rats; Rats, Sprague-Dawley; Remifentanil; Reperfusion Injury; Transaminases

To assess the effects of ischemic postconditioning, remote ischemic postconditioning and naloxone postconditioning on focal cerebral ischemia-reperfusion injury in rats.. A total of 110 adult SD rats were randomly divided into 5 groups (n = 22 each). The focal cerebral ischemia-reperfusion injury was induced by a 90-minute occlusion of right middle cerebral artery (MCA) and a 24-hour reperfusion sequentially. Group 1 was of ischemia-reperfusion control; Group 2 ischemic postconditioning induced by three 30-second cycles of MCA occlusion followed by a 30-second reperfusion; Group 3 remote ischemic postconditioning performed via a transient occlusion of right femoral artery at 5 min before the initiation of reperfusion; Group 4 naloxone postconditioning with naloxone 10 mg/kg intraperitoneally injected at the initiation of reperfusion; Group 5 combined ischemic, remote ischemic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2, 3 & 4. The neurologic deficit scores (NDS) were obtained at 2 h & 24 h post-reperfusion. At 24 h post-reperfusion, the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to assess the size of cerebral infarct (n = 10), detect the cerebral expression of microtubule-associated protein-2 (MAP2) (n = 6), measure the plasma volume of cerebral tissues and quantify the diameter and segment length of cerebral microvessel (n = 6).. There were no significant differences in the heart rate (HR) and mean arterial pressure (MAP) among the above five groups at all observed time points (P > 0.05). At 24 h post-reperfusion, the percentage of ischemic cerebral infarct size was 43% ± 6%, 31% ± 4%, 32% ± 5%, 28% ± 6% & 21% ± 7% in ipsilateral hemisphere area (i.e., cerebral infarct severity) in Groups 1-5 respectively. Compared with Group 1, the levels of NDS and cerebral infarct severity significantly decreased at ischemic side in Groups 2-5 (P < 0.05). And the cerebral expression of MAP2, plasma volume of cerebral tissues, diameter and segment length of cerebral microvessel significantly increased at the ischemic side (all P < 0.05). However, there were no significant differences in the above-mentioned parameters at ischemic side among Groups 2, 3 and 4 (all P > 0.05). The parameters of NDS, cerebral infarct severity, cerebral expression of MAP2 and plasma volume of cerebral tissues in the ischemic side significantly increased in Group 5 compared with Groups 1, 2, 3 and 4 (all P < 0.05). The diameter and segment length of cerebral microvessel at ischemic side were not different among Groups 2, 3, 4 and 5 (all P > 0.05).. In focal cerebral ischemia-reperfusion rats, ischemic, remote ischemic and naloxone postconditioning may produce significant neuroprotective effects of reduced cerebral infarct severity and improved neurologic dysfunctions. A combination of three postconditioning approaches enhances the above neuroprotective effects.

Topics: Animals; Brain Ischemia; Ischemic Postconditioning; Male; Naloxone; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Morphine treatment for 5 days protects heart against ischemia-reperfusion (IR) injury. This study evaluated the involvement of nitric oxide (NO) in morphine-induced renal protection. Three weeks after right nephrectomy, increasing doses of morphine were administered (20-30 mg kg(-1)day(-1), 5 days) to develop dependence in rats. The left kidney underwent 45-min ischemia and 24-h reperfusion. Some rats were pretreated with naloxone (5 mg kg(-1)) or L-NAME (20 mg kg(-1)). In one group, IR was induced 24h after the last dose of morphine during the withdrawal period. Plasma nitrite/nitrate levels and serum creatinine and BUN were measured. Creatinine clearance and fractional excretion of sodium (FE(Na)) were calculated. Myeloperoxidase (MPO) activity, malondialdehyde (MDA) level, and inducible NO synthase (iNOS) expression were determined and histopathology was studied in the left kidney. IR increased serum creatinine and BUN, plasma NO (p<0.01), FE(Na), iNOS expression (p<0.001), MPO activity, MDA level, and tissue damage and decreased creatinine clearance. Morphine decreased plasma NO (p<0.05 vs IR), serum creatinine and BUN (p<0.01), FE(Na), MPO activity, MDA level, iNOS expression, and tissue damage (p<0.05), but increased creatinine clearance (p<0.05). Pretreatment with naloxone significantly increased NO production and iNOS expression in morphine-treated rats after IR (p<0.01 vs morphine dependence+IR). Pretreatment with L-NAME in morphine-treated rats decreased NO production (10.7+/-1.9, p<0.01 vs morphine dependence+IR) but could not change iNOS expression after IR. Both naloxone and L-NAME significantly abolished the protective effects of morphine dependence on functional and histological factors. The protective effect of morphine dependence on serum creatinine, BUN, FE(Na), and creatinine clearance persisted during the withdrawal period, whereas iNOS expression decreased. NO production was not decreased during the withdrawal period (p>0.1 vs morphine dependence+IR group). Morphine dependence provided renal protection in the acute phase and during withdrawal. Excessive increase or decrease in NO production abolished the effects of morphine, which suggested a role for balanced NO production and iNOS expression.

Topics: Animals; Blood Urea Nitrogen; Creatinine; Cytoprotection; Kidney; Male; Malondialdehyde; Morphine; Morphine Dependence; Naloxone; Nephrectomy; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase Type II; Peroxidase; Rats; Rats, Wistar; Reperfusion Injury

To investigate the effects of morphine administered after reperfusion in a rabbit model of ischemic retinopathy.. The right eyes of 54 albino New Zealand rabbits were randomly allocated into nine treatment groups (n = 6 in each group). The eyes in saline-control group received 0.1 mL of phosphate-buffered saline solution intravitreally. In the ischemia-saline group, ischemia was induced by raising the intraocular pressure to 150 mmHg for 60 minutes. Then 0.1 mL of phosphate-buffered saline solution was administered intravitreally 5 minutes after reperfusion. The eyes in three ischemia-morphine groups (ischemia-morphine 0 hour, 1 hour, and 18 hours) received 0.1 mL of morphine (10 micromol/L) intravitreally 5 minutes, 1 hour, or 18 hours after termination of 60 minutes of ischemia, respectively. The eyes in ischemia-naloxone-morphine group received 0.05 mL of naloxone (10 micromol/L) intravitreally followed by injection of 0.05 mL morphine (10 micromol/L) 5 minutes after termination of ischemia. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (10 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day.. Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in ischemia-saline group compared with that of the saline-control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane (a measure of inner retinal thickness) was significantly increased due to edema (P < 0.001). Administration of morphine 5 minutes after reperfusion significantly improved all of the above mentioned indices compared with ischemia-saline group (P < 0.001). Administration of morphine 1 hour after reperfusion had also a significant effect on the improvement of above mentioned indices compared with saline-control group (P < 0.05). However, the number of ganglion cells was significantly higher in ischemia-morphine 0 hour group compared with ischemia-morphine 1 hour group (P < 0.001). Morphine treatment 18 hours after reperfusion did not change the amount of injury. Administration of naloxone 5 minutes before morphine abolished most of the morphine protective effects.. Intravitreal administration of morphine immediately after reperfusion maximally protects retina against ischemia-reperfusion injury. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opioid receptors.

Topics: Analgesics, Opioid; Animals; Disease Models, Animal; Injections; Male; Morphine; Naloxone; Narcotic Antagonists; Rabbits; Reperfusion Injury; Retina; Retinal Diseases; Retinal Ganglion Cells; Time Factors; Vitreous Body

In nonocular systems, activation of opioid receptors has been shown to ameliorate tissue damage induced by ischemic stress. The current study was an investigation of whether opioid receptors activated by endogenous or exogenous agonists can ameliorate ischemic retinal injury.. In an investigation of whether endogenous opioid receptor-activation reduces ischemic injury, the effects of the opioid antagonist naloxone (3 mg/kg; IP) on retinal neuroprotection induced by ischemic preconditioning (IPC) were evaluated. Whether exogenous opioid administration can reduce ischemic retinal injury was determined by pretreating rats with morphine (0.01-10 mg/kg) before injury. Morphometric and electroretinogram (ERG) analyses were used to assess the differences in retinal structure and function. The expression of opioid receptor subtypes was evaluated by Western blot and immunohistochemical analyses.. In control animals, 7 days after ischemic retinal injury, ERG a- and b-wave amplitudes were significantly reduced (23% and 41%, respectively). In addition, degeneration of the inner retina resulted in a 34% reduction in overall retina thickness. In animals receiving IPC before ischemic injury, ERG wave forms and retinal morphology were preserved. Pretreatment with naloxone reversed both the functional and structural retinal protection induced by IPC. In animals treated with morphine 24-hours before ischemic injury, ERG waveforms were preserved in a dose-dependent fashion (ED(50) = 0.18 mg/kg), and this protective response was reversed by naloxone pretreatment. Immunohistochemical and Western blot data demonstrated that the delta-, kappa-, and mu-opioid receptor subtypes are expressed in the retina.. These data provide evidence that activation of one (or more) opioid receptor(s) facilitates the development of IPC within the retina and can reduce ischemic retina injury.

Topics: Animals; Blotting, Western; Electroretinography; Female; Immunohistochemistry; Ischemic Preconditioning; Male; Morphine; Naloxone; Narcotic Antagonists; Narcotics; Rats; Rats, Inbred BN; Receptors, Opioid; Reperfusion Injury; Retinal Degeneration; Retinal Vessels

To demonstrate that a modern theory of paraplegia prevention in thoracoabdominal aortic (TAAA) surgery is primarily non-anatomic and derives from experimentally validated interventions that prolong the ischemic tolerance, reduce reperfusion injury, and enhance the collateral perfusion of the spinal cord with or without assisted circulation.. Using an accurate predictive model (r(2) > 0.95) for paraplegia risk we studied the effects of protective strategies in 82 clinical series reporting more than 15,000 patients treated from 1985 to 2008. The observed/expected (O/E) ratios were calculated for each series and the results were grouped by technique. The effect of interventions such as spinal fluid drainage (SFD), systemic hypothermia, epidural cooling, and naloxone on O/E ratios were studied. We analyzed changes in O/E ratios from Era 1 (1985 to 1997) to Era 2 (1997 to 2008) and within treatment techniques over time.. The mean O/E ratio for paraplegia for all patients declined from 1.13 in Era 1 to 0.26 in Era 2. Adding SFD to patients treated with assisted circulation (AC) decreased the O/E ratio from 1.03 to 0.24 (P < .0001). Adding SFD to patients treated with aortic clamping without AC (XCL) decreased O/E from 0.91 to 0.23 (P = .0013). O/E for hypothermic arrest (HA) declined from 0.42 to 0.14 with SFD. The addition of SFD to AC, XCL, and HA accounted for most of the decline in O/E between Eras. Other factors which played a less defined but important role in the decline in O/E ratios were attention to higher mean arterial pressures (MAPs), more hypothermia, and neurochemical protection.. Paraplegia causation is anatomic but paraplegia prevention is physiologic (non-anatomic). We demonstrate that by using hypothermia, SFD, and increasing MAP, clinicians had similar improvements in paraplegia, reducing O/E deficit ratios from 1.03 to as low as 0.16, with or without intercostal reimplantation, and whether or not assisted circulation was used. Understanding the fundamental principles of paraplegia prevention and how to apply protective strategies leads to a reduction in paralysis in clinical series with or without the use of assisted circulation. This modern theory of paraplegia has significant implications for the rapidly advancing field of TAAA repair with branched endografts where the same principles apply.

Topics: Aortic Aneurysm, Thoracic; Assisted Circulation; Blood Pressure; Collateral Circulation; Constriction; Drainage; Humans; Hypothermia, Induced; Logistic Models; Models, Biological; Naloxone; Neuroprotective Agents; Paraplegia; Reperfusion Injury; Risk Assessment; Spinal Cord Ischemia; Time Factors; Treatment Outcome; Vascular Surgical Procedures

The present study was designed to investigate the possible role of opioids and K(ATP) channels in ischemic postconditioning-induced reversal of global cerebral ischemia and reperfusion (I/R) induced neuronal injury. Mice were subjected to global ischemia by bilateral carotid artery occlusion for 10 min followed by reperfusion for 24 h, to produce neuronal injury. Ischemic postconditioning was induced by three episodes of carotid artery occlusion and reperfusion of 10 s each, immediately after global ischemia. Morphine postconditioning was induced by administration of morphine (5 mg/kg i.v.), 5 min prior to reperfusion. Naloxone (5 mg/kg i.v.), opioid receptor antagonist, and glibenclamide (5 mg/kg i.v.), K(ATP) channel blocker were administered 10 min before global ischemia. Extent of cerebral injury was assessed by measuring cerebral infarct size using triphenyl tetrazolium chloride (TTC) staining. Short-term memory was evaluated using the elevated plus maze test, while degree of motor incoordination was evaluated using inclined beam-walking, rota-rod and lateral push tests. Bilateral carotid artery occlusion followed by reperfusion resulted in significant increase in infarct size, impairment in short-term memory and motor co-ordination. Ischemic/morphine postconditioning significantly attenuated I/R induced neuronal injury and behavioural alterations. Pretreatments with naloxone and glibenclamide attenuated the neuroprotective effects of ischemic/morphine postconditioning. It may be concluded that ischemic/morphine postconditioning protects I/R induced cerebral injury via activating opioid receptor and K(ATP) channel opening.

Topics: Analgesics, Opioid; Animals; Cerebral Infarction; Ischemic Attack, Transient; Ischemic Preconditioning; KATP Channels; Male; Memory, Short-Term; Mice; Morphine; Naloxone; Narcotic Antagonists; Narcotics; Postural Balance; Psychomotor Performance; Reperfusion Injury

Postconditioning is a novel strategy of attaining cardioprotection. Previous studies have suggested morphine mimics the effects of ischemic preconditioning. Whether it is also capable of producing postconditioning or not is still unclear. The purpose of this study was to determine (1) whether morphine postconditioning (MPostcond) would protect the heart against reperfusion injury and the subtype(s) of opioid receptors (OR) involved, (2) whether combining MPostcond with morphine preconditioning (MPC) would afford additive cardioprotection, and (3) to evaluate the role mitochondrial adenosine triphosphate-sensitive potassium (mito-K atp) channel played in MPostcond.. Isolated perfused rat hearts were subjected to 45 min of ischemia followed by 1 h of reperfusion. First, three morphine concentrations (0.3, 3.0 and 30 microM) were used to study the protective effect of MPostcond. Second, the effect of blockade of OR subtypes by three antagonists (nonselective OR antagonist naloxone, kappa-OR antagonist nor-binaltorphimine, and delta-OR antagonist naltrindole) on MPostcond was investigated. Third, the protective effects of MPC, MPostcond and the combining MPC with MPostcond on reperfusion injury were compared. Last, the effect of blockade of mito-K atp by 5-hydroxydecanoate on MPostcond was studied. MPostcond was induced by a 10-min perfusion of morphine in Krebs-Ringer's solution performed at the onset of reperfusion, and MPC was produced by a 20-min perfusion of morphine 10 min before ischemia. Infarct size (IS/AAR, as a percentage of the area at risk) was determined by 2,3,5-triphenyltetrazolium staining.. IS/AAR was significantly reduced after MPostcond from 58% +/- 8% (control) to 37% +/- 6% (morphine 3.0 microM, P < 0.01). This effect was abolished by coadministering naloxone (58% +/- 7%), nor-binaltorphimine (52% +/- 5%), but not naltrindole (34% +/- 5%). MPC and MPostcond had similar extent of protective effect on IS/AAR, and combining MPC with MPostcond did not afford further cardiprotection. 5-Hydroxydecanoate also abolished the cardioprotection of MPostcond. Unexpectedly, all three OR antagonists and 5-hydroxydecanoate themselves also afforded some extent of cardioprotection.. MPost confers cardioprotection via activating kappa-OR but not delta-OR and opening mito-K atp channels. MPost and MPC have no additive protection. kappa-OR and mito-K atp channel may play a dual role in protecting ischemia-reperfusion injury.

Topics: Analgesics, Opioid; Animals; Anti-Arrhythmia Agents; Cardiotonic Agents; Decanoic Acids; Dose-Response Relationship, Drug; Hydroxy Acids; In Vitro Techniques; Ischemic Preconditioning, Myocardial; Male; Morphine; Myocardial Infarction; Naloxone; Naltrexone; Narcotic Antagonists; Potassium Channels; Rats; Rats, Sprague-Dawley; Reperfusion Injury

To investigate the effect of methylprednisolone (MP) and naloxone (Na) on pulmonary ischemia/reperfusion (I/R) injury in rats and to study its possible mechanism.. Seventy male Sprague-Dawley (SD) rats were used for reproduction of unilateral lung ischemia/reperfusion (I/R) injury, and they were randomly divided into five groups (14 rats in each group): sham operation group (sham group), I/R group, MP group,Na group, and MP+Na group. Each group was subdivided into two subgroups of 3-hour and 6-hour postinjury. I/R injury was produced by 45 minutes of cross-clamping of the pulmonary artery, followed by 3 hours or 6 hours of reperfusion. Apoptosis rate in lung tissue was assessed by the use of Annexin-V-PI with flow cytometry. Expression of I Kappa B-alpha and caspase-3 in lung tissue were observed by immunohistochemical stain and image analysis. The wet to dry weight (W/D) ratio, the pathological and ultrastructure changes in lung tissue were observed.. (1) The expression of I Kappa B-alpha in lung was obviously lower in I/R group than in 6-hour MP group (P<0.01), while expression of caspase-3 in lung tissue was significantly less intense in 3-hour and 6-hour Na group compared with I/R group (both P<0.05). Apoptosis rate in lung tissue was obviously lower in MP and 3-hour and 6-hour Na group than in I/R group (both P<0.01). The pathological and ultrastructure changes in lung tissue were less intensive. (2) Apoptosis rate, caspase-3 of lung tissue were significantly lower in MP+Na group than of 6-hour in MP, Na, I/R groups (P<0.05 or P<0.01) while the expression of I Kappa B-alpha was higher than of 6-hour Na group. The pathological and ultrastructure change in lung tissue were less more mark in MP+Na group than in other groups.. MP and Na inhibit apoptosis in lung I/R injury by either decreasing the activation of I Kappa B-alpha or caspase-3.MP and Na when used together in early period of lung I/R injury could exert more effective protection to lung tissue.

Topics: Animals; Apoptosis; Caspase 3; Disease Models, Animal; I-kappa B Proteins; Lung; Male; Methylprednisolone; Naloxone; NF-KappaB Inhibitor alpha; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Cerebral ischemia/reperfusion involves inflammatory process and naloxone is able to reduce infarct volume and has been used as a therapeutic agent for brain injury. Hypoxia induces the immediate early genes (IEGs) rapidly and transiently that may initiate a cascade of cellular responses that are necessary for survival and normal function. However, the protective effect of naloxone on ischemic/hypoxic neuronal cells was only partly studied. Thus, the effects of naloxone on oxygen- and glucose-deprivation (OGD) and OGD followed by reoxygenation (OGD/R) on the expression of IEGs were examined in PC12 cells. The result showed that lactate dehydrogenase (LDH) released in the media was reduced by naloxone. The temporal response of IEG mRNA encoding c-fos, c-jun, nur77, and zif268 was induced with different degree of intensity following hypoxia, whereas the level of GAPDH mRNA was relatively constant. However, these signals of c-fos, c-jun, and nur77 by hypoxia were reduced significantly by naloxone. Treatment with OGD also activated mitogen-activated protein kinase (MAPK) pathway. The induction of c-fos, c-jun, nur77, and zif268 by hypoxia was inhibited by naloxone (0.1 microM) and MAPK inhibitors (10 microM of U0126, D98059, SB203580). However, naloxone increased the expression of ERK1/2 by OGD concomitantly diminished the LDH release. Thus, the present studies demonstrated that OGD induced IEGs including c-fos, c-jun, nur77, and zif268 and MAPK signaling pathways were regulated differently by naloxone.

Topics: Animals; Brain Infarction; Cytoprotection; DNA-Binding Proteins; Encephalitis; Enzyme Inhibitors; Gene Expression Regulation; Genes, Immediate-Early; Hypoxia-Ischemia, Brain; L-Lactate Dehydrogenase; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 3; Naloxone; Narcotic Antagonists; Neurons; Neuroprotective Agents; Nuclear Receptor Subfamily 4, Group A, Member 1; Oxidative Stress; PC12 Cells; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Rats; Receptors, Steroid; Reperfusion Injury

Pretreatment with thaliporphine before ischemia affords cardioprotective effects against reperfusion injury via antioxidant activity. This study evaluated whether thaliporphine administered at a certain period after myocardial ischemia conferred the same cardioprotection and assessed its possible new mechanism. The left main coronary artery of anaesthetized rats was occluded for 1 h and then reperfused for 2 h. Thaliporphine was administered at 10 min before reperfusion. Controls received saline only. Morphine, a nonselective opioid receptor agonist, was used as reference compound at 0.3 mg/kg. Thaliporphine at 0.05 and 0.5 mg/kg were found to reduce the infarct size. Recovery of cardiac function was higher in thaliporphine (0.5 mg/kg) group, as assessed by a significant improvement in the rates of pressure development (+dp/dt (max)). This compound also reduced plasma creatine kinase and cardiac MPO activity. These protective effects afforded by thaliporphine were diminished by the opioid receptor antagonists (naloxone or naltrexone) and by the mitochondrial K(ATP) blocker 5HD. In comparison, morphine reduced infarct size and MPO activity in the myocardium but produced slightly improvement in cardiac function after ischemia-reperfusion. These results demonstrate that reperfusion therapy with thaliporphine protect cardiac injury through further mechanism via activation of opioid receptor and opening of mitochondrial K(ATP) channels as morphine but with stronger activity.

Topics: Adenosine Triphosphate; Analgesics, Opioid; Animals; Antioxidants; Aporphines; Creatine Kinase; Dose-Response Relationship, Drug; Heart; Male; Mitochondria; Morphine; Myocardial Ischemia; Myocardium; Naloxone; Naltrexone; Narcotic Antagonists; Peroxidase; Plant Extracts; Potassium; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Risk; Time Factors

A patient underwent repair of a thoracoabdominal aortic aneurysm. Epidural morphine, 4 mg, was given for pain relief. After anesthesia, the patient displayed lower extremity paraparesis. This effect was reversed by naloxone. The authors sought to confirm these observations using a rat spinal ischemia model to define the effects of intrathecal morphine administered at various times after reflow on behavior and spinal histopathology.. Spinal cord ischemia was induced for 6 min using an intraaortic balloon. Morphine or saline, 30 microg, was injected intrathecally at 0.5, 2, or 24 h after reflow. In a separate group, spinal cord temperature was decreased to 27 degrees C before ischemia. After ischemia, recovery of motor function was assessed periodically using the motor deficit index (0 = complete recovery; 6 = complete paraplegia).. After ischemia, all rats showed near-complete recovery of function by 4-6 h. Intrathecal injection of morphine at 0.5 or 2 h of reflow (but not at 24 h) but not saline caused a development of hind limb dysfunction and lasted for 4.5 h (motor deficit index score = 4-6). This effect was reversed by intrathecal naloxone (30 microg). Intrathecal morphine administered after hypothermic ischemia was without effect. Histopathological analysis in animals that received intrathecal morphine at 0.5 or 2 h after ischemia (but not at 24 h) revealed dark-staining alpha motoneurons and interneurons. Intrathecal saline or spinal hypothermia plus morphine was without effect.. These data indicate that during the immediate reflow following a noninjurious interval of spinal ischemia, intrathecal morphine potentiates motor dysfunction. Reversal by naloxone suggests that this effect results from an opioid receptor-mediated potentiation of a transient block of inhibitory neurons initiated by spinal ischemia.

Topics: Aged; Analgesics, Opioid; Animals; Aortic Aneurysm, Abdominal; Aortic Valve Stenosis; Constriction; Dyskinesia, Drug-Induced; Female; Humans; Hypothermia, Induced; Injections, Spinal; Male; Morphine; Naloxone; Narcotic Antagonists; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Spinal Cord; Spinal Cord Ischemia; Tissue Fixation; Vascular Surgical Procedures

The interrelationship between the hypothalamic-pituitary-adrenal (HPA) activity and expression of central opioids is determined in ischemic Sprague-Dawley rats to support the therapeutic role of naloxone against cerebral ischemia. Two-month old rats received bilateral common carotid artery occlusion plus unilateral (right side) middle cerebral artery occlusion for 90 min under the anesthesia, and followed by reperfusion for various times. The plasma contents of adrenocorticotropin (ACTH) and RNA expression levels of proopiomelanocortin (POMC) were then determined in ischemic rats with or without naloxone treatment. Results showed that ischemia stimulates but reperfusion suppresses the activity of HPA axis. The induced expression of POMC at striatum and cortex areas appears to suppress the release of ACTH from the HPA axis. The suppression on the other hand is prevented by naloxone.

Topics: Adrenocorticotropic Hormone; Animals; Brain Ischemia; Cerebral Cortex; Cerebrovascular Circulation; Corpus Striatum; Down-Regulation; Homeostasis; Hypothalamo-Hypophyseal System; Naloxone; Narcotic Antagonists; Opioid Peptides; Pituitary-Adrenal System; Pro-Opiomelanocortin; Rats; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger

This study investigated the protective effects of ischemic preconditioning on intestinal ischemic injury and the role of endogenous opioid peptides (EOP) in these effects. Ischemia-reperfusion (I/R) induced by 30-min of ischemia and 60-min of reperfusion significantly increased the levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) and resulted in serious intestinal edema (wet weight/dry weight). The ischemic preconditioning (PC) elicited by three 8-min occlusion periods interspersed with 10-min reperfusion markedly attenuated intestinal injury caused by ischemia-reperfusion. Pretreatment with morphine (300 microg x kg(-1), i.v.) 10-min before ischemia and reperfusion mimicked the protection produced by PC. Naloxone (3 mg x kg(-1), i.v.) abolished the protection of morphine-induced preconditioning and ischemic preconditioning in rat intestine. However, there were no changes between naloxone alone and control groups. Treatment with naloxone before ischemia-reperfusion had no effect on animals compared with the I/R group. In addition, we also measured the content of endogenous opioid peptides (Leu-enkephalin) in the effluent which was collected before and during preconditioning. It was shown that the release of leu-enkephalin was markedly increased during preconditioning. These results suggested that EOP might play an important role in PC in rat small intestine.

Topics: Analgesics, Opioid; Animals; Drug Interactions; Edema; Enkephalin, Leucine; Intestinal Diseases; Intestinal Mucosa; Intestine, Small; Ischemia; Ischemic Preconditioning; L-Lactate Dehydrogenase; Male; Malondialdehyde; Morphine; Naloxone; Narcotic Antagonists; Opioid Peptides; Rats; Rats, Wistar; Receptors, Opioid; Reperfusion Injury

The pathogenesis of cerebral ischemia/reperfusion (I/R) involves cytokine/chemokine production, inflammatory cell influx, astrogliosis, cytoskeletal protein degradation and breakdown of the blood-brain barrier. (-)-Naloxone is able to reduce infarct volume and has been used as a therapeutic agent for cerebral I/R injuries. However, its effects on the mentioned pathophysiologic changes have scarcely been addressed. Cerebral I/R was produced by occluding and opening bilateral common carotid artery and unilateral middle cerebral artery in Sprague-Dawley rats. After cerebral I/R, the degradation of neuronal microtubule-associated protein-2 (MAP-2) was strongly associated with astrogliosis, inflammatory cell infiltration, cytokine/chemokine overproduction, and matrix metalloproteinase-9 activation. (-)-Naloxone pretreatment suppresses post-ischemic activation and preserves more MAP-2 protein. Therefore, (-)-naloxone administration might be an effective therapeutic intervention for reducing ischemic injuries.

Topics: Animals; Brain Ischemia; Cerebral Cortex; Glial Fibrillary Acidic Protein; Male; Matrix Metalloproteinase 9; Microtubule-Associated Proteins; Naloxone; Narcotic Antagonists; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Whether naloxone may modulate energy metabolism and endogenous antioxidant enzyme activities in ischemic cortex was studied. Cerebral ischemia/reperfusion (I/R) was produced by occluding two common carotid arteries and the right middle cerebral artery for 90 min followed by reperfusion in anesthetized Sprague-Dawley rats. Both pre-treatment (0.03 or 0.3 mg) and post-treatment (0.3 mg) of naloxone by intracerebroventricular infusion significantly reduced cortical infarct volumes. Pre-treatment with 0.03 mg reduced ischemia-induced suppression of extracellular pyruvate level and enhancement of lactate/pyruvate ratio as well as cerebral I/R-induced increases of endogenous catalase, glutathione peroxidase, and manganese superoxide dismutase activities. In conclusion, neuroprotective effects of naloxone in terms of reducing brain infarction involve attenuation of the disturbance of cellular functions following cerebral I/R via restoration of mitochondrial activities or energy metabolism.

Topics: Animals; Antioxidants; Brain; Catalase; Energy Metabolism; Free Radicals; Glutathione Peroxidase; Ischemic Attack, Transient; Lactic Acid; Male; Microdialysis; Naloxone; Narcotic Antagonists; Opioid Peptides; Pyruvic Acid; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stroke; Superoxide Dismutase

1. An investigation into whether reperfusion hyperalgesia is modulated by prior systemic administration of two benzodiazepine agonists (diazepam and chlordiazepoxide), and an antagonist (flumazenil) was conducted. 2. Transient ischaemia was induced in conscious rats by applying an inflatable tourniquet to the base of the tail; when the rats exhibited a co-ordinated escape response, the tourniquet was deflated and reperfusion of the tail was allowed. Reperfusion hyperalgesia manifested as a decrease in tail flick latency, following tail immersion in 49 degrees C water, after the release of the tourniquet. 3. Intraperitoneal administration of diazepam, chlordiazepoxide and flumazenil had no effect on the co-ordinated escape to the noxious ischaemic stimulus nor on tail flick latency after application of a sham tourniquet. 4. The hyperalgesia evident during reperfusion, was abolished by diazepam (1 and 5 mg kg-1) and chlordiazepoxide (5 and 25 mg kg-1). The antihyperalgesic effects of both diazepam (5 mg kg-1) and chlordiazepoxide (25 mg kg-1) were inhibited by flumazenil (1 mg kg-1). 5. Rotarod performance was impaired in rats given diazepam and chlordiazepoxide at the same doses at which the benzodiazepines were antihyperalgesic. The impairment to motor function did not extend to the motor systems involved in the tail flick response. 6. In conclusion, benzodiazepines have antinociceptive properties during hyperalgesia.

Topics: Animals; Behavior, Animal; Benzodiazepines; Chlordiazepoxide; Depression, Chemical; Diazepam; Dose-Response Relationship, Drug; Flumazenil; Hyperalgesia; Ischemia; Male; Motor Activity; Naloxone; Pain Measurement; Rats; Rats, Sprague-Dawley; Receptors, Opioid; Reperfusion Injury; Tail

The purpose of this study was to determine whether gamma-hydroxybutyrate provides protection against intestinal ischemia/reperfusion injury and to compare its effect with that of allopurinol and vitamin E. Thirty minutes of total regional ischemia, followed by 3 hours of reperfusion, produced intestinal damage that was completely prevented by gamma-hydroxybutyrate pretreatment. Naloxone partially blocked this protective effect. Allopurinol provided only partial protection against this injury, whereas vitamin E provided none. Treatment with gamma-hydroxybutyrate after ischemia but before reperfusion also provided significant protection. This study clearly demonstrates that gamma-hydroxybutyrate provides significant protection against intestinal ischemic injury and that it may do so via an opiate receptor-mediated mechanism.

Topics: Allopurinol; Animals; Cricetinae; Hydroxybutyrates; Intestines; Ischemia; Male; Mesocricetus; Naloxone; Reperfusion Injury; Sodium Oxybate; Vitamin E