AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 4 510-R515, Copyright © 1984 by American Physiological Society
Temperature sensitivity of the renin-angiotensin system in Ambystoma tigrinum
E. Corwin, G. M. Malvin, S. Katz and R. L. Malvin
The presence of a renin-angiotensin system was demonstrated in the
poikilotherm Ambystoma tigrinum, commonly called the tiger salamander.
Standard radioimmunoassay techniques were employed to measure the
intrarenal renin activity (IRA) and the plasma renin activity (PRA) of A.
tigrinum kept at either 5 or 20 degrees C. Basal IRA and PRA values were
not affected by the temperature at which the animals were maintained.
Intraperitoneal injection of the beta-adrenergic agonist isoproterenol,
however, increased PRA only in those animals maintained at 20 degrees C.
This is consistent with the hypothesis of a temperature sensitivity of the
renal adrenergic system in vivo. In addition, we were able to demonstrate
the existence of a contractile response of Ambystoma vascular smooth muscle
to angiotensin II that was blocked by the competitive inhibitor saralasin.
