AJP - Regulatory, Integrative and Comparative Physiology, Vol 245, Issue 2 259-R264, Copyright © 1983 by American Physiological Society
Angiotensin II in the renal excretory response to behavioral stress in conscious dogs
J. P. Koepke and P. A. Obrist
The effects of inhibition of the renin-angiotensin system on the decreased
renal excretion of sodium and water resulting from behavioral stress (shock
avoidance) were examined in conscious saline-infused (4-5 ml/min) dogs.
During saline infusion alone in six dogs, avoidance decreased sodium
excretion (64% from 329 mueq/min) and urine flow (63% from 1.9 ml/min).
During converting enzyme inhibition with captopril in the same dogs, the
decreases in sodium excretion (35% from 464 mueq/min) and urine flow (35%
from 2.6 ml/min) during avoidance were attenuated. Similarly, in six other
dogs, avoidance decreased sodium excretion (41% from 361 mueq/min) and
urine flow (43% from 2.1 ml/min) with saline infusion alone. During
angiotension II (ANG II) receptor antagonism with saralasin, decreases in
sodium excretion (29% from 417 mueq/min) and urine flow (27% from 2.2
ml/min) were attenuated. These mean changes in excretion during inhibition
of the renin-angiotensin system were significantly (P less than 0.05) less
than during saline alone. Whereas decreases in fractional sodium and water
excretion were attenuated by renin-angiotensin inhibition, decreases in
glomerular filtration rate and effective renal blood flow and increases in
mean arterial pressure were not affected. These results indicate that ANG
II contributes to the renal excretory response to avoidance.
