Evidence for endothelin-induced renal vasoconstriction independent of ET(sub A) receptor activation

The role of the endothelin receptor ET-A in mediating the renal hemodynamic response to endothelin-1 (ET-1) was examined. ET-A is one of two ET receptor types and is believed to mediate the potent vasoconstrictor effects of ET-1. The study protocol involved the observation of the effects of BQ-123, a selective ET-A antagonist, on the renal hemodynamics during intravenous infusion of ET-1 in the rat. The results suggest a role for ET-A in the maintenance of renal vascular resistance and arterial pressure. However, ET-A does not mediate ET-1 renal vasoconstrictor events.