scholarly journals Neuroprotective Efficacy of Repinotan HCl, a 5-HT1A Receptor Agonist, in Animal Models of Stroke and Traumatic Brain Injury

2005 ◽  
Vol 25 (4) ◽  
pp. 451-459 ◽  
Author(s):  
Frank Mauler ◽  
Ervin Horváth
Keyword(s):  
Animal Models ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Receptor Agonist ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Occlusion Model ◽  
Neuroprotective Efficacy ◽  
Cerebral Artery Occlusion

Repinotan is a highly potent 5-HT1A receptor agonist with strong neuroprotective efficacy in animal models of middle cerebral artery occlusion and traumatic brain injury. In this study, we characterized the time window for neuroprotective effects of repinotan in animal models. In the permanent middle cerebral artery occlusion model, repinotan showed neuroprotective efficacy when administered as a triple bolus injection (0.3–100 μg/kg) or an intravenous infusion (0.3–100 μg/kg per hour). A 73% reduction in infarct volume was observed with a 3 μg/kg intravenous bolus, and a 65% reduction was observed with a 3 and 10 μg/kg per hour intravenous infusion. When delayed until 5 hours after occlusion, repinotan (10 μg/kg per hour) reduced infarct volume by 43%. In the transient middle cerebral artery occlusion model, repinotan (10 μg/kg per hour) administered immediately after occlusion reduced infarct volume by 97%, and a delay to 5 hours reduced infarct volume by 81%. In the acute subdural hematoma model, repinotan (3 and 10 μg/kg per hour) reduced infarct volume by 65%. In this model, repinotan (3 μg/kg per hour) administered 5 hours after occlusion reduced infarct volume by 54%. The favorable neuroprotective efficacy, broad dose–response curve, and prolonged therapeutic window observed in all models strongly suggest that repinotan is a promising candidate for treating acute ischemic stroke in humans.

MitoKATP opener, diazoxide, reduces neuronal damage after middle cerebral artery occlusion in the rat

2002 ◽  
Vol 283 (3) ◽  
pp. H1005-H1011 ◽  
Author(s):  
Katsuyoshi Shimizu ◽  
Zsombor Lacza ◽  
Nishadi Rajapakse ◽  
Takashi Horiguchi ◽  
James Snipes ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Ischemia Reperfusion Injury ◽  
Neuronal Damage ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Sham Treatment ◽  
Cerebral Artery Occlusion

We investigated effects of diazoxide, a selective opener of mitochondrial ATP-sensitive K+ (mitoKATP) channels, against brain damage after middle cerebral artery occlusion (MCAO) in male Wistar rats. Diazoxide (0.4 or 2 mM in 30 μl saline) or saline (sham) was infused into the right lateral ventricle 15 min before MCAO. Neurological score was improved 24 h later in the animals treated with 2 mM diazoxide (13.8 ± 0.7, n = 13) compared with sham treatment (9.5 ± 0.2, n = 6, P < 0.01). The total percent infarct volume (MCAO vs. contralateral side) of sham treatment animals was 43.6 ± 3.6% ( n = 12). Treatment with 2 mM diazoxide reduced the infarct volume to 20.9 ± 4.8% ( n = 13, P < 0.05). Effects of diazoxide were prominent in the cerebral cortex. The protective effect of diazoxide was completely prevented by the pretreatment with 5-hydroxydecanoate (100 mM in 10 μl saline), a selective blocker of mitoKATP channels ( n = 6). These results indicate that selective opening of the mitoKATP channel has neuroprotective effects against ischemia-reperfusion injury in the rat brain.

Abstract 11511: Genetic Variation in Retinal Vascular Patterning Predicts Variation in Pial Collateral Extent and Infarct Volume After Middle Cerebral Artery Occlusion

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Pranay Prabhakar ◽  
Hua Zhang ◽  
De Chen ◽  
Stephen Lockett ◽  
James E Faber
Keyword(s):  
Genetic Variation ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Genetic Background ◽  
Infarct Volume ◽  
Indirect Evidence ◽  
Artery Occlusion ◽  
Stroke Severity ◽  
Cerebral Artery Occlusion

Introduction: The presence of a native (pre-existing) collateral circulation in tissues lessens injury in stroke and other occlusive diseases. However, differences in genetic background are accompanied by wide variation in the number and diameter (extent) of native collaterals in mice, resulting in large variation in protection. Indirect evidence suggests a similar wide variation also exists in humans. However, methods of measurement in humans are indirect, invasive and not widely available. Hypothesis: We sought to determine if differences in genetic background in mice result in variation in branch-patterning of the retinal circulation, and if these differences predict differences in collateral extent and, in turn, differences in severity of ischemic stroke. Methods: Patterning metrics were obtained for the retinal arterial trees of 10 mouse strains (n=8 per strain) that differ widely in collateral extent in brain and other tissues. We also obtained pial collateral number and diameter, and infarct volume 24h after permanent middle cerebral artery occlusion. Forward- and reverse-stepwise multivariate regression analysis was conducted and model performance assessed using K-fold cross-validation. Results: Twenty-one metrics varied significantly with genetic strain (p<0.01). Ten metrics (eg, vessel caliber, bifurcation angle, lacunarity, optimality, branch length) strongly predicted collateral number and diameter across 7 regression models. The best models closely predicted (p<0.0001) collateral number (K-fold R 2 =0.83-0.98), diameter (0.73-0.88) and infarct volume (0.85-0.87). Conclusions: Differences in retinal tree patterning are specified by genetic background and closely predict genetic variation in pial collateral extent and, in turn, stroke severity. If these findings can be confirmed in humans, and given that genetic variation in cerebral collaterals extends to other tissues at least in mice, a similar “retinal predictor index” could be developed as a biomarker for collateral extent in brain and other tissues. This could aid prediction of the risk-severity of tissue injury in occlusive disease as well as stratification of patients for treatment options and enrollment in clinical studies.

Melatonin and calpeptin synergistically protect against post-reperfusion injury in a rat middle cerebral artery occlusion stroke model

2021 ◽  
Vol 4 (4) ◽  
pp. 592-612
Author(s):  
Ye Feng ◽  
Qian Xu ◽  
Raymond Tak Fai Cheung
Keyword(s):  
Cerebral Ischemia ◽  
Middle Cerebral Artery ◽  
Reperfusion Injury ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Neurological Deficit ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Stroke Model ◽  
Cerebral Artery Occlusion

Cerebral ischemia induces oxidative injury and increases the intracellular calcium ion concentration to activate several calcium-dependent proteases such as calpains. Calpain activation leads to various necrotic and apoptotic processes. Calpeptin is a potent, cell-permeable calpain inhibitor. As a strong antioxidant and free radical scavenger, melatonin shows beneficial effect in rodent models of focal cerebral ischemia when given prior to ischemia or reperfusion. This study was focused on the neuroprotective effects of melatonin and/or calpeptin given after onset of reperfusion. For this purpose, right-sided middle cerebral artery occlusion (MCAO) for 90 minutes followed by 24 or 72 hours of reperfusion was performed in male Sprague Dawley rats, then, melatonin 50 or 150 µg/kg, calpeptin 10, 15 or 50 µg/kg or a combination of melatonin 50 µg/kg plus calpeptin 15 or 50 µg/kg were injected via an intracerebroventricular route at 15 minutes after onset of reperfusion. Melatonin or calpeptin tended to reduce the relative infarct volume and significantly decreased the neurological deficit at 24 hours. The combination achieved a greater protection than each of them alone. Melatonin, calpeptin or the combination all decreased Fluoro-Jade B (FJB)+ degenerative neurons and cleaved/total caspase-3 ratio at 24 hours. These treatments did not significantly impact the density of surviving neurons and ED-1+ macrophage/activated microglia. At the 72-hour-reperfusion, melatonin or the combination decreased the relative infarct volume and neurological deficit. Nevertheless, only the combination reduced FJB+ degenerating neurons at 72 hours. In conclusion, a combination of melatonin and calpeptin exerted synergistic protection against post-reperfusion injury in a rat MCAO stroke model.

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