Cardiovascular effects of vasopressin following V1 receptor blockade compared to effects of nitroglycerin

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 281; no. 3; p. 887
• Main Authors: Cooke, C. R, Wall, B. M, Huch, K. M, Mangold, T
• Format: Journal Article
• Language: English
• Published: 01.09.2001
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.2001.281.3.r887

Department of Medicine, Veterans Affairs Medical Center and University of Tennessee Health Sciences Center, Memphis, Tennessee 38104 Studies to more clearly determine the mechanisms associated with arginine vasopressin (AVP)-induced vasodilation were performed in normal subjects and in quadriplegic subjects with impaired efferent sympathetic responses. Studies to compare the effects of AVP with the hemodynamic effects of nitroglycerin, an agent that primarily affects venous capacitance vessels, were also performed in normal subjects. Incremental infusions of AVP following V 1 -receptor blockade resulted in equivalent reductions in systemic vascular resistance (SVRI) in normal and in quadriplegic subjects. However, there were major differences in the effect on mean arterial pressure (MAP), which was reduced in quadriplegic subjects but did not change in normal subjects. This difference in MAP can be attributed to a difference in the magnitude of increase in cardiac output (CI), which was twofold greater in normal than in quadriplegic subjects. These observations are consistent with AVP-induced vasodilation of arterial resistance vessels with reflex sympathetic enhancement of CI and are clearly different from the hemodynamic effects of nitroglycerin, i.e., reductions in MAP, CI, and indexes of cardiac preload, with only minor changes in SVRI. vasopressin 1-receptor antagonist; hemodynamic effects