Role of H2S in Regulation of Vascular Tone in Metabolic Disorders.

We studied the effect of the H2S donor (NaHS, 1-500 µM) on the contractile responses of isolated aortic smooth muscle segments from rats with metabolic syndrome induced by high-fat, high-carbohydrate diet. It was found that the vasorelaxing effect of NaHS (5-100 µM) decreased in under conditions of MS. The endothelial NO synthase inhibitor L-NAME (100 µM) suppressed the effect of NaHS, while cystathionine-gamma-lyase inhibitor PAG (100 µM) decreased the vasodilating effects of acetylcholine (0.1-100 µM). Application of endogenous NO precursor L-arginine (1 mM) potentiated in the effects of H2S donor NaHS. Thus, the contractile activity of vascular smooth muscles in metabolic syndrome is determined by not only the effect of H2S, but also the influence of NO.