AJP - Heart and Circulatory Physiology, Vol 235, Issue 1 29-H33, Copyright © 1978 by American Physiological Society
Influence of low- and high-pressure baroreceptors on plasma renin activity in humans
A. L. Mark, F. M. Abboud and A. E. Fitz
We evaluated effects of the low- and high-pressure baroreceptors on plasma
renin activity (immunoassay) using graded lower body suction (LBS) in six
healthy men. LBS at -10 and -20 mmHg for 10 min decreased central venous
pressure without changing arterial pressure and thereby presumably reduced
low- but not high-pressure baroreceptor inhibition of renin release. LBS at
these levels produced forearm vasoconstriction, but did not increase renin.
LBS at -40 mmHg decreased central venous and arterial pulse pressure and
thus reduced both low- and high-pressure baroreceptor inhibition. LBS at
this level produced forearm vasoconstriction and tachycardia and increased
renin from 2.1 +/- 0.4 (mean +/- SE to 7.4 +/- 1.4 ng.ml-1.h-1 (P less than
0.05). In summary, reduction in low-pressure baroreceptor inhibition in
humans did not increase renin in the presence of physiological tonic
inhibition from high-pressure baroreceptors. Increases in renin did not
occur until there was combined reduction of high- and low-pressure
baroreceptor inhibition on plasma renin activity.
