AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 6 1472-R1478, Copyright © 1994 by American Physiological Society
Interaction between angiotensin II and nitric oxide in control of renal hemodynamics in conscious dogs
A. M. Alberola, F. J. Salazar, T. Nakamura and J. P. Granger
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson 39216-4505.
Recent in vitro studies have provided evidence that the vasoconstrictor
actions of angiotensin II on afferent arterioles are enhanced by nitric
oxide synthesis inhibition. Although these studies suggest that nitric
oxide may play a role in protecting the afferent arterioles from
angiotensin II-induced vasoconstriction, the importance of this interaction
in the regulation of glomerular filtration rate and renal blood flow in the
intact, conscious animal is not known. The objective of the present study
was to determine the role of nitric oxide in modulating the renal
hemodynamic and excretory effects of angiotensin II. Angiotensin II was
infused at rates of 0.5, 1.0, and 2.0 micrograms.kg-1.min-1 intrarenally in
conscious, chronically instrumented dogs in both the presence and absence
of nitric oxide synthesis inhibition by continuous intrarenal infusion of
NG-nitro-L-arginine methyl ester (3 micrograms.kg-1.min-1). At a dose of
0.5 micrograms.kg-1.min-1, angiotensin II decreased renal plasma flow by
19%, while having no effect on glomerular filtration rate in control dogs.
In contrast, angiotensin II decreased renal plasma flow by 54%, glomerular
filtration rate by 40%, and increased renal vascular resistance by 125% in
the presence of intrarenal nitric oxide synthesis blockade. At doses of 1.0
and 2.0 micrograms.kg-1.min-1, angiotensin II reduced renal plasma flow by
36 and 45%, glomerular filtration rate by 17 and 23%, and increased renal
vascular resistance by 80 and 120%, respectively, in control dogs.(ABSTRACT
TRUNCATED AT 250 WORDS)
