AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 5 641-R644, Copyright © 1985 by American Physiological Society
Mechanism of inhibition of renin secretion by increased left atrial pressure
M. E. Lee, T. N. Thrasher and D. J. Ramsay
Experiments were designed to elucidate the mechanism of the failure of
systemic hypotension to stimulate renin release in the presence of elevated
left heart pressure. We conducted a series of graded ascending aortic and
suprarenal cuff inflations in dogs with bilateral renal denervation (n =
5). The renal perfusion pressure (RPP) was reduced by 10, 20, and 30% of
control by inflation of either cuff. Comparison of the renin response with
inflation of the ascending aortic to the suprarenal cuff revealed a clear
increase in the threshold required to elicit a renin response to graded
reduction of RPP after inflation of the ascending aortic cuff. These
results may be explained by differential effects of the two maneuvers on
left heart pressure. Left atrial pressure increased during inflation of the
ascending aortic cuff but did not change during inflation of the suprarenal
cuff. Since the kidneys were denervated, the shift in threshold must be
caused by a humoral substance(s). In conclusion, our findings suggest that
the efferent pathway of potent inhibition of renin release from the left
heart is mediated, at least partially, by a humoral substance.
