Document Detail


Atrial natriuretic factor, angiotensin II, and the slow component of renal autoregulation.
MedLine Citation:
PMID:  7882177     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Autoregulation of renal blood flow is highly efficient and is mediated partly by tubuloglomerular feedback (TGF), which couples regulation of blood flow to that of sodium excretion. Atrial natriuretic factor (ANF) dilates preglomerular resistance vessels, in which autoregulation occurs, and has been reported to inhibit TGF. This study addressed potential actions of ANF on the slow, TGF-mediated, component of autoregulation. Renal blood flow was measured by an electromagnetic flow probe in Sprague-Dawley rats anesthetized by halothane or isoflurane while renal perfusion pressure was manipulated by a servo-controlled clamp placed on the aorta between the renal arteries. Progressive reduction of perfusion pressure to 60 mmHg (1 mmHg = 133.3 Pa) induced resetting of autoregulation to operate at the reduced pressure and to defend lower renal blood flow. Infusion of ANF at a dose shown to reliably increase sodium excretion did not affect autoregulation or its resetting. Because resetting is angiotensin II dependent, the converting enzyme inhibitor Enalaprilat was used to provide angiotensin II blockade. As expected, autoregulation did not reset to operate at reduced perfusion pressure. Again ANF was without effect. In a third experiment, relaxation of resistance was assessed in response to repeated steps of perfusion pressure between 65 and 75 mmHg. Time constants of constriction and dilatation were recovered by fitting to a single exponential before and during ANF infusion. Time constants ranged form 0.045 to 0.055 Hz, were consistent with operation of TGF, were not different for constriction or dilatation, and were unaltered by ANF; nor did ANF affect the magnitude of constriction or dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
R E Naguib; C Contant; W A Cupples
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  72     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1994 Oct 
Date Detail:
Created Date:  1995-04-12     Completed Date:  1995-04-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  1132-7     Citation Subset:  IM    
Affiliation:
Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, Montréal, QC, Canada.
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MeSH Terms
Descriptor/Qualifier:
Angiotensin II / metabolism*
Animals
Atrial Natriuretic Factor / metabolism*
Enalaprilat / pharmacology
Homeostasis / drug effects
Male
Rats
Rats, Sprague-Dawley
Renal Circulation / drug effects,  physiology*
Chemical
Reg. No./Substance:
11128-99-7/Angiotensin II; 84680-54-6/Enalaprilat; 85637-73-6/Atrial Natriuretic Factor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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