EFFECTS OF SUPEROXIDE-DISMUTASE ON NITRIC-OXIDE PRODUCTION DURING REPERFUSION AFTER FOCAL CEREBRAL-ISCHEMIA IN RATS

To assess the interaction of nitric oxide (NO) and superoxide during r eperfusion after cerebral ischemia, we studied the dose effects of sup eroxide dismutase (SOD) on the levels of nitrosyl hemoglobin and plasm a nitrite + nitrate which were increased at 30 min reperfusion after 2 h middle cerebral artery occlusion in rats. SOD was administered at 1 0 min before reperfusion. With 1, 5 and 10 mg/kg of SOD, plasma nitrit e + nitrate was not changed, although nitrosyl hemoglobin level was in creased with 5 mg/kg SOD. However, plasma nitrite + nitrate level was decreased by 25 mg/kg of SOD. The same amount of apo enzyme was withou t effect. These results suggest effect of superoxide in the NO level r eleased during reperfusion after cerebral ischemia.