Inhibition of nitric oxide synthesis increases blood pressure in healthy humans

    loading  Checking for direct PDF access through Ovid


Objective:To examine whether endogenous production of the endotheliumderived vasodilator nitric oxide influences blood pressure in healthy humansMethods:After preliminary pilot dose-ranging studies, 3mg/kg NG-monomethyl-l-arginine (l-NMMA), an inhibitor of nitric oxide synthase, and saline placebo were infused intravenously over 5 min to eight healthy subjects in a two-phase, randomized, single-blind crossover study. Blood pressure and cardiac and renal function were measuredResults:Compared with placebo, L-NMMA increased mean arterial pressure by 10%, decreased heart rate by 19%, decreased cardiac index by 25% and increased calculated total peripheral resistance by 46%. Effects were maximal 10-15 min after starting l-NMMA infusion. Urinary sodium and fractional sodium excretions were increased by l-NMMA, but creatinine clearance was unchangedConclusions:Basal generation of nitric oxide influences total peripheral resistance and blood pressure in healthy humans. The natriuresis induced by L-NMMA may be related to the increase in blood pressure, or arise from inhibition of the intrarenal actions of nitric oxide. Any decrease in nitric oxide generation, as has been postulated to occur in essential hypertension, could have substantial effects on blood pressure and tissue blood flow

    loading  Loading Related Articles