MELATONIN DECREASES PRODUCTION OF HYDROXYL RADICAL DURING CEREBRAL ISCHEMIA-REPERFUSION

AIM: To study the effect of melatonin on hydroxyl radical (. OH) conte nts during cerebral ischemia-reperfusion in rats. METHODS: Ischemia wa s induced by occluding left lateral middle cerebral artery for 30 min following reperfusion. The salicylate trapping method coupled with ips ilateral striatal microdialysis for measurement of hydroxyl radicals g enerated during ischemia and reperfusion. RESULTS: The contents of dih ydroxybenzoic acid (DHBA) were increased at 15 min after ischemia and remained high for 30 min after reperfusion. Melatonin (4 mg . kg(-1), sc, 30 min before ischemia) decreased the production of DHBA during is chemia for 16 - 30 min and reperfusion for 1 - 30 min. CONCLUSION: Mel atonin inhibits the production of hydroxyl radicals in rat brain durin g ischemia and reperfusion.