VOLTAMETRIC ASSESSMENT OF BRAIN NITRIC-OXIDE DURING HEATSTROKE IN RATS

Anesthetized rats exposed to a high ambient temperature develop heatst roke with brain ischemia. Since nitric oxide (NO) plays an important r ole during normothermic ischemia, its cortical and cerebellar producti on were continuously assessed in pentobarbital anesthetized rats expos ed to heat by using differential pulsed voltammetry. After 60 min at t hermoneutrality, the rats were submitted to an ambient temperature of 40 degrees C until death. After 60 min in the heat, the rats were inje cted intraperitoneally with saline, MK801 (1 mg.kg(-1)), an antagonist of N-methyl-D-aspartate (NMDA) receptors, or L-arginine p-nitroanilid e (L-ANA; 100 mg.kg(-1)), an inhibitor of NO synthase. Just before dea th, a 70% increase in NO production was observed in both the cerebellu m and the cortex of saline-treated rats. The cortical increase in NO w as not modified by MK801 while the NO signal was suppressed by L-ANA. (C) 1997 Elsevier Science Ireland Ltd.