Bradykinin b2 receptor antagonist increases chloride and water
absorption in rat medullary collecting duct.
Mukai, Hiroya, Wayne R. Fitzgibbon, Gary Bozeman, Harry S. Margolius,
and David W. Ploth.
Divsion of Nephrology, Department of Medicine, Departments of Cell
and Molecular Pharmacology and Experimental Therapeutics, and
Medicine and Department of Urology, Medical University of South
Carolina, Charleston, SC, 29425 and the Ralph H. Johnson Veteran's
Affairs Medical Center, Charleston, SC, 29403
APStracts 3:0072R, 1996.
This study tested the hypothesis that intrarenal kinins play a
regulatory role in electrolyte excretion by altering Cl- absorption
in the collecting duct. We measured [Cl-] and [inulin] in tubular
fluid samples obtained from medullary collecting ducts (MCD) of Dahl
SR/Jr rats by microcatheterization of ducts of Bellini prior to and
following treatment with the bradykinin receptor antagonist, HOE 140.
Tubular fluid was obtained from paired terminal inner medulla (t
-IMCD) and outer medulla (OMCD) collecting duct sites of the left
kidney. HOE 140 (n=7) or vehicle (n=5) was infused i.v., and the
collections were repeated. HOE 140 did not alter GFR but decreased
urine flow rate (p<0.05) and absolute and fractional Cl-
excretion (p<0.01). HOE 140 did not alter the fraction of
filtered Cl- delivered (FDCl) to the OMCD but decreased FDCl to the
t-IMCD from 2.3+/-0.3% to 1.3+/-0.3% (p<0.05). The fraction of
filtered Cl- absorbed/mm between the collection sites was increased
from 0.2+/-0.1 to 0.6+/-0.1% (p<0.05). Fractional absorption of
water along the MCD was also increased (p<0.05). No changes in
excretory function or tubular Cl- or water absorption were observed
in vehicle-treated rats. These studies show that kinin B2 receptor
blockade enhances Cl- and water absorption in the MCD, a finding that
supports a role of renal kinins in the regulation of Na/Cl and water
excretion.
Received 30 November 1995; accepted in final form 15 February
1996.
APS Manuscript Number R753-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 March 96