N-acetylcysteine potentiates platelet inhibition by endothelium-derived relaxing factor.

Recent evidence suggests that endothelium-derived relaxing factor exhibits properties of nitric oxide. Like nitric oxide, it inhibits platelet function and mediates its effects by elevating intracellular cyclic GMP. In this study we have investigated the role of reduced thiol in the mechanism of action of endothelium-derived relaxing factor on platelets.

S-nitrosocaptopril. I. Molecular characterization and effects on the vasculature and on platelets.

We have synthesized an S-nitrosylated derivative of captopril, S-nitrosocaptopril, that manifests nitrosovasodilatory activity, inhibits angiotensin converting enzyme activity and inhibits platelet aggregation. The direct vasodilatory effects of S-nitrosocaptopril reflect the effects of the thionitrite bond, the presence of which does not in any way influence S-nitrosocaptopril's ability to inhibit angiotensin converting enzyme. Thionitrite stimulation of both vascular and platelet soluble guanylate cyclase activity leads to increases in intracellular cyclic GMP that are accompanied by vasodilatation and platelet inhibition, respectively.