AJP - Heart and Circulatory Physiology, Vol 244, Issue 2 253-H258, Copyright © 1983 by American Physiological Society
Pressor responses of rats to vasopressin: effect of sodium, angiotensin, and catecholamines
M. Burnier and H. R. Brunner
The pressor response to lysine vasopressin was tested in groups of male
Wistar, Brattleboro, Wistar-Kyoto, and spontaneously hypertensive rats.
Moreover, the influence of sodium intake, angiotensin II, saralasin,
captopril, norepinephrine, and isoproterenol on vasopressin pressor
responses was evaluated. The right iliac artery and one or both femoral
veins of the animals were catheterized under light ether anesthesia. The
experiments were carried out following a 2-h stabilization period with the
rats awake and semirestrained. Pressor responsiveness was evaluated acutely
on the basis of dose-response curves (0.5-4 mU). In the Wistar rats,
angiotensin II (10 and 30 ng/min) and isoproterenol (10 ng/min) markedly
decreased the response to vasopressin, whereas variations in sodium intake
and blood pressure per se did not seem to exert any influence.
Norepinephrine (250 ng/min) slightly enhanced the pressor responsiveness to
the smaller doses of lysine-vasopressin. Brattleboro rats with congenital
diabetes insipidus were less sensitive to vasopressin than the other
animals, and neither angiotensin II nor isoproterenol induced any change.
In conclusion, the pressor responsiveness to vasopressin can vary
considerably depending on several factors. These must be taken into account
when evaluating the possible pressor role of vasopressin in experimental
and clinical settings.
