Endothelium-dependent relaxation of rat aorta induced by resveratrol

Abstract

It has been noted that there are a number of biologically active phenolic compounds present in wine, particularly red wine. Such compounds include, for example, catechin, epicatechin, quercetin, rutin, trans-resveratrol and cis-resveratrol. The resveratrol isomers, in particular, have been found to promote vascular relaxation. The mechanisms by which resveratrol causes vasodilatation are uncertain. The aim of this study was to investigate the mechanism(s) of resveratrolinduced vasorelaxation in rat aorta with endothelium present. Rat aortic rings were precontracted with phenylephrine. Resveratrol induced relaxation of the rat aortic rings. L-NAME, an inhibitor of NO synthase, abolished relaxation of rat aorta, but methylene blue, an inhibitor of guanylate cyclase, did not abolish relaxation induced by resveratrol. Highly selective blocker of ATP-sensitive K+ channels, glibenclamide as well as a nonselective blocker of big Ca-sensitive K+ channels, charybdotoxin did not block resveratrol-induced relaxation of rat aorta. 4-Aminopiridine, which is a non selective blocker of voltage-gated K+ (Kv) channels, and margatoxin which inhibits Kv1 channels abolished relaxation of rat aortic rings induced by resveratrol. In conclusion, we have shown that resveratrol potently relaxed rat aortic rings with endothelium present. It seems that NO and smooth muscle KV channels are included in this relaxation. This finding is of clinical importance in both veterinary and human medicine.