EFFECTS OF NITRIC-OXIDE SYNTHASE INHIBITION ON CEREBRAL BLOOD-FLOW FOLLOWING BILATERAL CAROTID-ARTERY OCCLUSION AND RECIRCULATION IN THE RAT

The effects of bilateral carotid artery occlusion/recirculation on cortical CBF (cCBF) were studied in rats following the intravenous administration of either the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME; 30 mg/kg) or an equivalent volume of saline (500 mul). Induction of bilateral carotid occlusion (BCO) in L-NAME-treated animals resulted in a reduction of cCBF to 30% of baseline. During recirculation subsequent to 20 min of BCO, cCBF in L-NAME-infused animals remained at 30% of baseline. In contrast, cCBF in saline-treated control animals returned to the original baseline level following a similar reduction to 30-40% of baseline during BCO. These results indicate that inhibition of nitric oxide generation limits normalization of regional cortical perfusion following occlusion of proximal large cerebral vessels.