The first Robert Furchgott lecture: from endothelium-dependent relaxation to the L-arginine:NO pathway.

Nitric oxide (NO) is released from vascular endothelial cells and fresh vascular tissue in amounts sufficient to account for the biological actions of endothelium-derived relaxing factor. It is synthesized from the terminal guanidino nitrogen atom(s) of L-arginine, a process that is inhibited by NG-monomethyl-L-arginine (L-NMMA). Studies using L-NMMA have shown that NO is constantly generated by the vessel wall to maintain vasodilator tone. The L-arginine:NO pathway has now been identified in a number of other cells and tissues, in many of which it acts as the transduction mechanism for stimulation of the soluble guanylate cyclase.