Hyperlipidemic arterial dysfunction.

About 10 years ago, Furchgott and Zawadzki2 /... made a remarkable observation that helped .Lk.clarify variable effects of acetylcholine on arterial tone. They demonstrated that isolated arteries relaxed in response to acetylcholine and other endogenous vasoactive agents only in the presence of an intact endothelium and postulated that endothelial cells released a diffusible vasodilator principle, which they called endothelium-derived relaxing factor (EDRF).2-4 Current evidence indicates that EDRF is a nitric acid radical (NO) or a precursor thereof (S-nitrosothiol) apparently derived from the terminal guanidino atom(s) of L-arginine.4,5 Stimulation of endothelial muscarinic receptors produces a rise in cytosolic calcium, the intracellular signal evoking release of EDRF. Numerous endogenous agents,