Melatonin decreases production of hydroxyl radical during cerebral ischemia-reperfusion.
AIM
To study the effect of melatonin on hydroxyl radical (.OH) contents during cerebral ischemia-reperfusion in rats.


METHODS
Ischemia was induced by occluding left lateral middle cerebral artery for 30 min following reperfusion. The salicylate trapping method coupled with ipsilateral striatal microdialysis for measurement of hydroxyl radicals generated during ischemia and reperfusion.


RESULTS
The contents of dihydroxybenzoic 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 ischemia for 16-30 min and reperfusion for 1-30 min.


CONCLUSION
Melatonin inhibits the production of hydroxyl radicals in rat brain during ischemia and reperfusion.