Physiological role of endothelin in cardiovascular and renal hemodynamics: studies in animals

Even though the pharmacology of the endothelin receptor subtypes ETB and ETB is well characterized, their physiological role in the control of basal vascular tone is poorly understood. It has been proposed that a tonic vasoconstriction mediated by endothelin counterbalances a vasodilator tone mediated by nitric oxide, the major endothelium-derived relaxing factor. Recent evidence suggest that the endogenous endothelin-1, released from the endothelial cells, mediates both vasodilation and vasoconstriction and indicates the existence of a negative feedback system involving endothelin-1, the endothelial ETB receptor and nitric oxide.