HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/3/F811    most recent 90225.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sivritas, S.-H. Articles by Fitzgibbon, W. R. Search for Related Content PubMed PubMed Citation Articles by Sivritas, S.-H. Articles by Fitzgibbon, W. R.

Blockade of renal medullary bradykinin B₂ receptors increases tubular sodium reabsorption in rats fed a normal-salt diet

Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina

Submitted 31 March 2008 ; accepted in final form 11 July 2008

The present study was performed to test the hypothesis that under normal physiological conditions and/or during augmentation of kinin levels, intrarenal kinins act on medullary bradykinin B₂ (BKB₂) receptors to acutely increase papillary blood flow (PBF) and therefore Na⁺ excretion. We determined the effect of acute inner medullary interstitial (IMI) BKB₂ receptor blockade on renal hemodynamics and excretory function in rats fed either a normal (0.23%)- or a low (0.08%)-NaCl diet. For each NaCl diet, two groups of rats were studied. Baseline renal hemodynamic and excretory function were determined during IMI infusion of 0.9% NaCl into the left kidney. The infusion was then either changed to HOE-140 (100 µg·kg^–1·h^–1, treated group) or maintained with 0.9% NaCl (time control group), and the parameters were again determined. In rats fed a normal-salt diet, HOE-140 infusion decreased left kidney Na⁺ excretion (urinary Na⁺ extraction rate) and fractional Na⁺ excretion by 40 ± 5% and 40 ± 4%, respectively (P < 0.01), but did not alter glomerular filtration rate, inner medullary blood flow (PBF), or cortical blood flow. In rats fed a low-salt diet, HOE-140 infusion did not alter renal regional hemodynamics or excretory function. We conclude that in rats fed a normal-salt diet, kinins act tonically via medullary BKB₂ receptors to increase Na⁺ excretion independent of changes in inner medullary blood flow.

inner medullary collecting duct; inner medullary blood flow; renal hemodynamics; renal excretion