AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 5 1136-R1140, Copyright © 1992 by American Physiological Society
Effect of kinin receptor antagonists on renal hemodynamic and natriuretic responses to volume expansion
F. J. Fenoy and R. J. Roman
Department of Physiology, Medical College of Wisconsin, Milwaukee 53226.
The role of kinins in the natriuretic and papillary blood flow (PBF)
responses to intravenous administration of 0.9% sodium chloride solution
equal to 5% of body weight over 30 min was evaluated using a B1-kinin
receptor antagonist (des-Arg9, [Leu8]bradykinin, 2.5 micrograms/min i.v.)
and a B2-kinin receptor antagonist (D-Arg, [Hyp3,Thi5,8,D-Phe7]bradykinin,
2.5 micrograms/min i.v.). In control rats, PBF increased 43 +/- 5% after
the volume expansion with saline. Administration of the B1-kinin receptor
antagonist had no significant effect on basal PBF or the rise in PBF
produced by volume expansion. In contrast, administration of the B2-kinin
receptor antagonist decreased basal PBF by 18 +/- 3% and prevented the rise
in PBF during volume expansion. Urine osmolality was lower in the rats
treated with the B1-antagonist and higher in rats infused with the B2-kinin
antagonist than in control animals after volume expansion (587 +/- 47 and
1,082 +/- 83 vs. 907 +/- 124 mosmol/kgH2O, respectively). The initial
natriuretic response during the first 30 min after volume expansion was
similar in rats given vehicle or the kinin antagonists. However, cumulative
sodium excretion over the 2-h course of the experiment was significantly
lower in the rats given the B2-receptor antagonist than in control rats (92
+/- 7 vs. 101 +/- 9% of the administered load). The B1-kinin receptor
antagonist had no effect on cumulative sodium excretion; however,
glomerular filtration rate was 30% lower in rats receiving the
B1-antagonist than in control rats after volume expansion.(ABSTRACT
TRUNCATED AT 250 WORDS)
