HYPOTHERMIA SUPPRESSES NITRIC-OXIDE ELEVATION DURING REPERFUSION AFTER FOCAL CEREBRAL-ISCHEMIA IN RATS

We aimed to investigate effect of temperature on the jugular levels of nitric oxide (NO) at reperfusion after focal cerebral ischemia. Both nitrosyl hemoglobin (HbNO) (2.5 +/- 0.4 mu M) and plasma nitrite plus nitrate levels (61 +/- 5 mu M) in rats under normothermia (similar to 37 degrees C) after 30 min of reperfusion following 2 h of left middle cerebral artery occlusion were significantly high, compared with sham operated rats (1.3 +/- 0.1 mu M, 40 +/- 4 mu M, respectively). Both H bNO (1.5 +/- 0.3 mu M) and nitrite plus nitrate levels (43 +/- 7 mu M) under moderate hypothermia (similar to 32 degrees C) were significant ly low, compared with normothermic rats. HbNO (2.8 +/- 0.8 mu M) and n itrite plus nitrate levels (65 +/- 8 mu M) under mild hyperthermia (si milar to 39 degrees C) were not significantly high. These results firs tly demonstrated that hypothermia suppresses the elevation in intrajug ular NO after cerebral ischemia-reperfusion. Copyright (C) 1996 Elsevi er Science Ireland Ltd.