Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917798 (cerebral ischemia)
 17,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Opiate antagonists, including receptor antagonists and physiologic antagonists, have been shown to produce beneficial effects in a variety of models of CNS injury and in a variety of species. Opiate antagonists improve spinal cord blood flow, electrical conduction of the spinal cord, pathological changes, and motor recovery following traumatic spinal cord injury in cats. TRH appears to be superior to naloxone in this regard, although direct comparisons between receptor-selective opiate receptor antagonists and TRH have not been made. Similarly, opiate antagonists are effective in improving outcome and reducing pathological changes following ischemic spinal cord injury in rabbits. Beneficial effects for opiate receptor antagonists have also been observed after fluid percussion head injury in cats. Effects of opiate antagonists in the treatment of experimental stroke have been more controversial, although the weight of evidence supports a therapeutic effect in various models and species. Following spinal cord injury, best evidence suggests that pathophysiological responses produced by opioids may be mediated by the dynorphin opioid system and/or the kappa opiate receptor. This issue is of considerable importance, since it may lead to the development of more effective and specific forms of therapy. The role of specific opioid systems and specific opiate receptors in traumatic head injury or cerebral ischemia have not been adequately studied and should be the subject of future investigation. A number of controlled clinical studies are now either planned or under way to investigate the potential therapeutic effects of naloxone and TRH in CNS injury. Data from these studies should be available within the next several years.
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PMID:Role of thyrotropin-releasing hormone and opiate receptor antagonists in limiting central nervous system injury. 283 Jul 71

Naltrexone, a nonselective antagonist of opioid receptors, is found to be beneficial in protecting against heatstroke. Further investigation using selective mu, delta, and kappa opioid receptor antagonists are needed to prove the involvement of specific receptors in heatstroke. Rats under sodium pentobarbital anesthesia were exposed to high ambient temperature of 43 degrees C to induce heatstroke. Control rats were exposed to 24 degrees C. In rats treated with normal saline 20 minutes before heat stress, the values for survival time were found to be 89-101 minutes. Intravenous administration of CTAP (a selective mu-opioid receptor antagonist; 50-200 microg/kg), but not nor-binaltorphimine (20-200 microg/kg; a kappa-opioid receptor antagonist) or ICI-174864 (50-500 microg/kg; a delta-opioid receptor antagonist), significantly increased the survival time to new values of 180-212 minutes. In vehicle-treated rats after heatstroke onset, the values for core temperature, intracranial pressure, and the extracellular markers for ischemia (eg, glutamate and lactate/pyruvate ratio) or damage (eg, glycerol) and neuronal damage scores in striatum were significantly higher than those of normothermic controls. In contrast, the values for mean arterial pressure, cerebral perfusion pressure, cerebral blood flow, and brain partial pressure of O2 were significantly lower than those of normothermic controls. The heatstroke-induced hyperthermia, arterial hypotension, intracranial hypertension, cerebral hypoperfusion and hypoxia, and increased levels of cellular ischemia and damage markers in striatum were all significantly attenuated by prior administration of CTAP. The data indicate that prior antagonism of mu-opioid receptors protects against circulatory shock and cerebral ischemia during heatstroke.
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PMID:Mu-opioid receptor blockade protects against circulatory shock and cerebral ischemia during heatstroke. 1630 98

Alterations in the opioidergic system may play a role in the molecular mechanisms underlying neurochemical responses to cerebral ischaemia. The present study aimed to determine the delayed expression of mu, delta and kappa opioid receptors, following 1, 2, 7, and 30 days of middle cerebral artery occlusion (MCAO) in mice. Using quantitative autoradiography, we highlighted significant decreases in mu, delta and kappa opioid receptor expression in ipsilateral cortices from day 1 post-MCAO. Moreover, in contralateral nucleus lateralis thalami pars posterior, ipsi- and contralateral nucleus medialis dorsalis thalami, and ipsilateral substantia nigra, pars reticulata (SNr), kappa receptors were increased; mu receptor densities were decreased in nucleus ventralis thalami, pars posterior (VThP), and SNr. delta-Binding sites were increased in the striatum on day 30 post-MCAO. The alterations in opioid receptors in cortical infarcts were correlated with strong histological damage. Further reductions in opioid receptor densities in cortical infarcts were observed at later time points. In subcortical brain regions, opioid receptor densities were also altered but no histological damage was seen, except in the VThP, in which cell density was increased on day 30. Delayed reductions in opioid receptor densities in the infarct appeared as the continuation of the early processes previously demonstrated. However, changes in subcortical opioid receptor expression may correlate with neuronal alterations in remote brain regions. Changes in opioidergic receptor expression in these regions may be involved in the long-term consequences of stroke and could be used as biomarker of neuronal alteration through the use of imaging techniques in the clinic.
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PMID:Long-term alterations in mu, delta and kappa opioidergic receptors following middle cerebral artery occlusion in mice. 1767 26

Salvinorin A (SA) is a highly selective kappa opioid receptor (KOR) agonist that has significant protective effects on cerebrovascular function after ischemic stroke, but its underlying mechanism is still unclear. This study aimed to investigate whether KOR activation improves the morphology and function of intracellular mitochondria to protect endothelial cells after cerebral ischemia. A transient ischemic brain damage was generated by establishing middle cerebral artery occlusion (MCAO) model in male Sprague-Dawley rats and oxygen glucose deprivation (OGD) model in human brain microvascular endothelial cells (HBMECs). In vivo findings revealed that SA significantly reduced the infarct size, brain edema and Evans blue effusion after MCAO. In vitro findings revealed that SA improved the cell viability and decreased the apoptotic rates in HBMECs OGD model. SA also protected membrane potential and morphology of mitochondria, reduced the ROS level after OGD. SA function was blocked by KOR inhibitor norbinaltorphimine (NB). SA upregulated the phosphorylation levels of AMPK, and Mfn2 expression. Our findings suggest that SA effectively mitigated focal cerebral ischemic injury by activating KOR which potentially preserved mitochondrial function by up-regulating AMPK/Mfn2 in endothelial cells.
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PMID:Salvinorin A moderates postischemic brain injury by preserving endothelial mitochondrial function via AMPK/Mfn2 activation. 3146 37