BLOCKING EFFECTS OF OPC-21268 AND OPC-31260 (VASOPRESSIN V1-RECEPTOR AND V2-RECEPTOR ANTAGONISTS) ON VASOPRESSIN-INDUCED CONSTRICTIONS IN ISOLATED, PERFUSED DOG FEMORAL ARTERIES

Using a perfusion technique of isolated vessels, constrictor responses to vasopressin (VP) and norepinephrine (NE) were investigated in perfused dog femoral arteries. Both OPC-21268, a selective V1-antagonist, and OPC-31260, a selective V2-antagonist, significantly shifted the VP-induced dose response curves to the right without influencing the NE-induced ones. The blocking effects of OPC-31260 were much greater than those of OPC-21268, suggesting that there may probably be functional V1- and V2-receptors in isolated dog femoral arteries that mediate vasoconstriction.