Document Detail


Dynamic interaction between myogenic and TGF mechanisms in afferent arteriolar blood flow autoregulation.
MedLine Citation:
PMID:  11053046     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The dynamic activity of afferent arteriolar diameter (AAD) and blood flow (AABF) responses to a rapid step increase in renal arterial pressure (100-148 mmHg) was examined in the kidneys of normal Sprague-Dawley rats (n = 11) before [tubuloglomerular feedback (TGF)-intact] and after interruption of distal tubular flow (TGF-independent). Utilizing the in vitro blood-perfused juxtamedullary nephron preparation, fluctuations in AAD and erythrocyte velocity were sampled by using analog-to-digital computerized conversion, video microscopy, image shearing, and fast-frame, slow-frame techniques. These assessments enabled dynamic characterization of the autonomous actions and collective interactions between the myogenic and TGF mechanisms at the level of the afferent arteriole. The TGF-intact and TGF-independent systems exhibited common initial (0-24 vs. 0-13 s, respectively) response slope kinetics (-0.53 vs. -0.47% DeltaAAD/s; respectively) yet different maximum vasoconstrictive magnitude (-11.28 +/- 0.1 vs. -7. 02 +/- 0.9% DeltaAAD; P < 0.05, respectively). The initial AABF responses similarly exhibited similar kinetics but differing magnitudes. In contrast, during the sustained pressure input (13-97 s), the maximum vasoconstrictor magnitude (-7.02 +/- 0.9% DeltaAAD) and kinetics (-0.01% DeltaAAD/s) of the TGF-independent system were markedly blunted whereas the TGF-intact system exhibited continued vasoconstriction with slower kinetics (-0.20% DeltaAAD/s) until a steady-state plateau was reached (-25.9 +/- 0.4% DeltaAAD). Thus the TGF mechanism plays a role in both direct mediation of vasoconstriction and in modulation of the myogenic response.
Authors:
M Walker; L M Harrison-Bernard; A K Cook; L G Navar
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Renal physiology     Volume:  279     ISSN:  1931-857X     ISO Abbreviation:  Am. J. Physiol. Renal Physiol.     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2000-11-14     Completed Date:  2000-12-07     Revised Date:  2011-04-28    
Medline Journal Info:
Nlm Unique ID:  100901990     Medline TA:  Am J Physiol Renal Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  F858-65     Citation Subset:  IM    
Affiliation:
Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA. mwalker3@tulane.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Arterioles / physiology*
Blood Flow Velocity / physiology
Blood Pressure / physiology
Feedback / physiology
Kidney Glomerulus / blood supply*,  physiology
Kidney Tubules / blood supply*,  physiology
Male
Models, Cardiovascular
Nephrons / blood supply,  physiology
Rats
Rats, Sprague-Dawley
Regression Analysis
Renal Circulation / physiology*
Vascular Patency / physiology
Vasoconstriction / physiology
Grant Support
ID/Acronym/Agency:
HL-18426/HL/NHLBI NIH HHS

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


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