The cardiovascular effects and implications of peroxynitrite

Nitric oxide is an endogenous autacoid produced primarily by the vascular e ndothelium. Under basal conditions, nitric oxide undergoes a rapid biradica l reaction with superoxide anions to form peroxynitrite. This reaction, and hence the formation of peroxynitrite is augmented in inflammatory-like con ditions such as ischemia-reperfusion injury when both substrates are presen t in high concentrations. Peroxynitrite has been implicated as a physiologi cally active toxic metabolite of nitric oxide leading to vascular and myoca rdial dysfunction. Recent evidence, however, has suggested that peroxynitri te may actually have beneficial properties under in vivo biological conditi ons when thiol-containing agents (glutathione, albumin, cysteine) agents ar e available to convert the peroxynitrite anion to nitrosothiols and related products demonstrating antineutrophil and cardioprotective properties. The dichotomy of physiologically relevant properties of peroxynitrite has impo rtant clinical applications with respect to nitric oxide therapy for cardia c, vascular, cerebral and pulmonary disease states. This review summarizes the biological properties of peroxynitrite relevant to the cardiovascular s ystem. (C) 1999 Elsevier Science B.V. All rights reserved.