Document Detail

Resistance of ascending vasa recta to transport of water.
MedLine Citation:
PMID:  1705755     Owner:  NLM     Status:  MEDLINE    
A study was undertaken to determine the effect of increasing capillary pressure on volume flux in ascending vasa recta (AVR). In one experiment (group I), AVR were blocked by a single injection of paraffin wax and subjected to free-flow microperfusion at 10 nl/min. Collected fluid was obtained from the perfused vessels by micropuncture. In a second experiment (group II), AVR segments were isolated between two paraffin blocks and perfused at 10 nl/min. In group II, the collection pipette was pressurized to 0, 10, or 20 mmHg. Transmembrane volume flux was determined by measuring the change in concentration of fluorescein isothiocyanate-labeled dextran (2 x 10(6) mol wt) from perfusate to collected fluid. In group I, measurements revealed a capillary pressure of 10.3 +/- 0.5 (SE) mmHg and volume flux of 4.3 +/- 1.0 In group II, volume flux was 1.8 +/- 1.3, 5.9 +/- 1.0, and 11.2 +/- 1.1 at collection pressures of 0, 10, or 20 mmHg, respectively. Based on these data and an AVR diameter of 20 microns, AVR hydraulic conductivity is between 12.5 x 10(-6) and 18.7 x 10(-6) cm.s-1.mmHg-1. The papillary AVR have a high hydraulic conductivity. This is consistent with their role as the sole conduit for removal of water from the papillary interstitium.
T L Pallone
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  260     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1991 Mar 
Date Detail:
Created Date:  1991-04-11     Completed Date:  1991-04-11     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  F303-10     Citation Subset:  IM    
Division of Nephrology, M. S. Hershey Medical Center of Pennsylvania State University, Hershey 17033.
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MeSH Terms
Biological Transport
Body Water / metabolism*
Capillaries / metabolism
Dextrans / diagnostic use
Fluorescein-5-isothiocyanate* / analogs & derivatives*
Fluoresceins / diagnostic use
Kidney Medulla / blood supply*
Rats, Inbred Strains
Vascular Resistance*
Grant Support
Reg. No./Substance:
0/Fluoresceins; 0/fluorescein isothiocyanate dextran; 3326-32-7/Fluorescein-5-isothiocyanate; 9004-54-0/Dextrans

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

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