Document Detail

Frequency modulation of renal myogenic autoregulation by perfusion pressure.
MedLine Citation:
PMID:  17626123     Owner:  NLM     Status:  MEDLINE    
Recent studies of renal autoregulation have shown modulation of the faster myogenic mechanism by the slower tubuloglomerular feedback and that the modulation can be detected in the dynamics of the myogenic mechanism. Conceptual and empirical considerations suggest that perfusion pressure may modulate the myogenic mechanism, although this has not been tested to date. Here we present data showing that the myogenic operating frequency, assessed by transfer-function analysis, varied directly as a function of perfusion pressure in the hydronephrotic kidney perfused in vitro over the range from 80 to 140 mmHg. A similar result was obtained in intact kidneys in vivo when renal perfusion pressure was altered by systemic injection of N(G)-nitro-L-arginine methyl ester (L-NAME). When perfusion pressure was not allowed to increase, L-NAME did not affect the myogenic operating frequency despite equivalent reduction of renal vascular conductance. Blood-flow dynamics were assessed in the superior mesenteric artery before and after L-NAME. In this vascular bed, the operating frequency of the myogenic mechanism was not affected by perfusion pressure. Thus the operating frequency of the renal myogenic mechanism is modulated by perfusion pressure independently of tubuloglomerular feedback, and the data suggest some degree of renal specificity of this response.
Xuemei Wang; Rodger D Loutzenhiser; William A Cupples
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-11
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  293     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-08-31     Completed Date:  2007-10-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1199-204     Citation Subset:  IM    
Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
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MeSH Terms
Blood Pressure / physiology*
Enzyme Inhibitors / pharmacology
Feedback / physiology
Homeostasis / physiology*
Kidney / physiology*
Kidney Glomerulus / physiology
Kidney Tubules / physiology
NG-Nitroarginine Methyl Ester / pharmacology
Nitric Oxide Synthase / antagonists & inhibitors
Rats, Inbred BN
Rats, Long-Evans
Rats, Sprague-Dawley
Rats, Wistar
Renal Circulation / physiology*
Reg. No./Substance:
0/Enzyme Inhibitors; 50903-99-6/NG-Nitroarginine Methyl Ester; EC Oxide Synthase

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