AJP - Regulatory, Integrative and Comparative Physiology, Vol 240, Issue 5 276-R281, Copyright © 1981 by American Physiological Society

ARTICLES

Characterization of angiotensin pressor responses in the turtle Pseudemys scripta

J. E. Zehr, D. J. Standen and M. D. Cipolle

Studies were conducted in turtles (Pseudemys scripta) to characterize vascular responses to administration of exogenous angiotensin [Asp1-Ile5]angiotensin II (AII). Marked pressor responses were present following AII administration (2 microgram/kg iv). The pressor response was completely blocked by concomitant administration of an analogue of AII, [Sar1-Ile8]AII. Both alpha-receptor blockade with phenoxybenzamine or catecholamine depletion by reserpine administration reduced the pressor response approximately 50%. Further treatment with [Sar1-Ile8]AII completely blocked the AII pressor response. We conclude that the pressor response to AII in this species that represents an ancient group of reptiles includes a catecholamine-dependent component and direct vascular receptors, both of which are sensitive to AII.