[Biological effects of SIN-1 in the vascular wall]

The biological effects of two vasodilatory drugs, SIN-1 (the active metabolite of molsidomine) and nitroglycerin were analysed in the arterial endothelium and vascular muscle. Both drugs induce the secretion of prostacyclin in endothelial cells in culture, but this secretion is short-lived and occurs for high doses of the two drugs (above 10(-5)M). These same drugs induce a dose-dependent relaxing effect on the smooth muscle contracted either by norepinephrine or 5-hydroxytryptamine with an ED50 of 5.10(-7)M. This relaxation is neither secondary to an endothelium-derived product nor to a cyclooxygenase or lipoxygenase-derived product.