Is nitric oxide involved in the tonic inhibition of central sympathetic outflow in humans?

Abstract

Recent studies in experimental animals have advanced the concept that neuronal nitric oxide is an important component of the signal transduction pathways that tonically restrain sympathetic vasoconstrictor outflow from the brain stem. To determine whether or not this concept can be extended to the control of sympathetic outflow in humans, we recorded muscle sympathetic nerve activity (microelectrodes, peroneal nerve) in healthy human subjects during intravenous infusion of the nitric oxide synthase inhibitor N(G)- monomethyl-L-arginine (L-NMMA) (3.6 to 6.7 mg/kg). The major new finding is that during intravenous L-NMMA mean arterial pressure increased (10±2 mm Hg, P