Document Detail


Superficial and juxtamedullary nephron function during converting enzyme inhibition.
MedLine Citation:
PMID:  3014898     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The influence of the renin-angiotensin system on whole-kidney and regional single-nephron function was studied in anesthetized Munich-Wistar rats by use of a converting enzyme inhibitor (CEI), captopril (3 mg . h-1 . kg-1 body wt-1). Single-nephron glomerular filtration rate (SNGFR) was measured in superficial (S) and juxtamedullary (JM) nephrons by a micropuncture technique that blocked tubuloglomerular feedback (TGF) activity. Hydrostatic free-flow pressure (FFP) measurements were conducted in S proximal tubules, in JM loops of Henle, and in papillary vasa recta. Glomerular filtration rate (GFR) and urinary electrolyte excretion were measured in the contralateral kidney. In the control situation SNGFR of S nephrons was 35.4 +/- 2.24 nl . min-1 . g kidney wt-1 and of JM nephrons was 75.0 +/- 9.41 nl . min-1 . g-1 kidney wt-1. Thus it was more than twice as high in JM as in S nephrons when the TGF activity was blocked. In this situation administration of CEI had no additional effect on either S or JM nephrons. However, administration of CEI resulted in a significant increase in whole-kidney GFR by 25% (P less than 0.05) and in urine flow rate by 60% (P less than 0.001) under free-flow conditions. Further, intratubular FFP increased significantly in JM nephrons by an average of 2.9 +/- 0.52 mmHg (P less than 0.001), indicating an increase in tubular urine flow in JM nephrons, whereas S nephrons were unaffected. These results suggest an active preglomerular vasoconstriction in JM nephrons under normal free-flow conditions. This seems to be mediated by TGF and modulated by angiotensin II.
Authors:
A Göransson; M Sjöquist; H R Ulfendahl
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  251     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1986 Jul 
Date Detail:
Created Date:  1986-08-21     Completed Date:  1986-08-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  F25-33     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Angiotensin-Converting Enzyme Inhibitors*
Animals
Captopril / pharmacology
Electrolytes / urine
Glomerular Filtration Rate / drug effects
Kidney Tubules, Proximal / drug effects
Loop of Henle / drug effects
Male
Nephrons / drug effects,  physiology*
Pressure
Rats
Renin-Angiotensin System
Chemical
Reg. No./Substance:
0/Angiotensin-Converting Enzyme Inhibitors; 0/Electrolytes; 62571-86-2/Captopril

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


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