Arginine vasopressin enhances sympathetic constriction through the V1 vasopressin receptor in human saphenous vein

Abstract

Background - Arginine vasopressin (AVP) not only acts directly on blood vessels through V1 receptor stimulation but also may modulate adrenergic- mediated responses in animal experiments in vivo and in vitro. The aim of the present study was to investigate whether AVP can contribute to an abnormal adrenergic constrictor response of human saphenous veins. Methods and Results - Saphenous vein rings were obtained from 32 patients undergoing coronary artery bypass surgery. The vein rings were suspended in organ bath chambers for isometric recording of tension. AVP (3X 10-9 mol/L) enhanced the contractions elicited by electrical field stimulation at 1, 2, and 4 Hz (by 80%, 70%, and 60%, respectively) and produced a leftward shift of the concentration-response curve to norepinephrine (half-maximal effective concentration decreased from 6.87 X 10-7 to 1.04 X 10-7 mol/L; P