AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 1 74-R77, Copyright © 1983 by American Physiological Society
Role of vasopressin in blood pressure regulation in conscious water-deprived dogs
J. Schwartz and I. A. Reid
The role of vasopressin in the regulation of blood pressure during water
deprivation was assessed in conscious dogs with two antagonists of the
vasoconstrictor activity of vasopressin. In water-replete dogs, vasopressin
blockade caused no significant changes in mean arterial pressure, heart
rate, plasma renin activity (PRA), or plasma corticosteroid concentration.
In the same dogs following 48-h water deprivation, vasopressin blockade
increased heart rate from 85 +/- 6 to 134 +/- 15 beats/min (P less than
0.0001), increased cardiac output from 2.0 +/- 0.1 to 3.1 +/- 0.1 1/min (P
less than 0.005), and decreased total peripheral resistance from 46.6 +/-
3.1 to 26.9 +/- 3.1 U (P less than 0.001). Plasma renin activity increased
from 12.4 +/- 2.2 to 25.9 +/- 3.4 ng ANG I X ml-1 X 3 h-1 (P less than
0.0001) and plasma corticosteroid concentration increased from 3.2 +/- 0.7
to 4.9 +/- 1.2 micrograms/dl (P less than 0.05). Mean arterial pressure did
not change significantly. When the same dogs were again deprived of water
and pretreated with the beta-adrenoceptor antagonist propranolol, the heart
rate and PRA responses to the antagonists were attenuated and mean arterial
pressure decreased from 103 +/- 2 to 91 +/- 3 mmHg (P less than 0.001).
These data demonstrate that vasopressin plays an important role in blood
pressure regulation during water deprivation in conscious dogs.
