Rs. Wolfer et al., EXOGENOUS ARGININE-VASOPRESSIN DOES NOT ENHANCE CAROTID BAROREFLEX CONTROL IN THE CONSCIOUS DOG, The American journal of physiology, 266(5), 1994, pp. 180001510-180001516
Arginine vasopressin (AVP) has profound effects on the cardiovascular
system, yet has minimal presser activity at physiological levels in in
tact subjects. We designed an investigation to delineate the effects o
f AVP on open-loop carotid baroreflex control of mean arterial pressur
e (MAP), total peripheral resistance (TPR), and cardiac output (CO) in
conscious, chronically instrumented dogs. During graded infusions of
AVP (0.5-2.0 ng . kg(-1) . min(-1)), the open-loop hemodynamic respons
es to controlled changes in isolated carotid sinus pressure (CSP) were
determined. Increasing levels of AVP infusion led to significant incr
eases in plasma AVP levels (P < 0.01). Increasing doses of AVP led to
significant increases in TPR at all levels of CSP (P < 0.01). The over
all range and gain of the response were not significantly different at
any level of AVP infusion. Despite this increase in systemic resistan
ce, there was no significant change in the MAP-CSP relationship. Infus
ion of AVP led to a dose-dependent depression in CO (P < 0.01) and hea
rt rate (HR; P < 0.05) at all levels of CSP with no significant effect
on open-loop baroreflex control. We conclude that although exogenous
AVP induces profound changes in cardiovascular function, it does not a
lter carotid baroreflex control of MAP, TPR, CO, and HR.