Role of the l-arginine-nitric oxide pathway in the basal hydroxyl radical production in the striatum of awake rats as measured by brain microdialysis

Abstract

In the present study, using the microdialysis technique, we provided evidence of the existence of hydroxyl radicals ( ·OH) in the striatum of awake rats under physiological conditions. This ·OH generation was virtually abolished by the N-methyl- d-aspartate (NMDA) receptor antagonist dizocilpine. On the contrary, it was significantly enhanced by the ·NO synthase inhibitor N G-nitro- d-arginine methyl ester ( l-NAME). The effect of l-NAME was completely reversed by l-arginine. These results suggest that the basal ·OH production is largely the consequence of an NMDA receptor-mediated glutamatergic tone. Moreover, it is likely that endogenous ·NO exerts an antioxidant activity in brain by preventing the rise in ·OH levels.