Document Detail

Changes of cell volume and nitric oxide concentration in macula densa cells caused by changes in luminal NaCl concentration.
MedLine Citation:
PMID:  12397038     Owner:  NLM     Status:  MEDLINE    
The luminal NaCl concentration ([NaCl]) at the macula densa (MD) controls both tubuloglomerular feedback (TGF) and renin release. Nitric oxide (NO) inhibits TGF sensitivity to a great extent. The NO concentration in the MD cells is not known. This study measured this concentration in MD cells with confocal microscopy in the isolated perfused thick ascending limb using a NO-sensitive fluorophore 4,5-diaminofluorescein (DAF-2). Calcein was used to measure cell volume changes. The loop perfusion fluid was a modified Ringer solution containing 10, 35, or 135 mM NaCl with a constant total osmolarity (290 mOsm), and the bath was perfused with the 135 mM NaCl solution. The results show that MD cell volume and NO concentration measured with DAF-2 DA increased considerably with increasing luminal [NaCl] and with calcium-free solutions in the lumen and bath. L-arginine (5 mM) increased NO concentration in the MD cells by 30%. 7-nitroindazole could totally inhibit the NO production caused by L-arginine and by increased luminal [NaCl]. In conclusion, the MD cell volume changes caused by the changes of luminal [NaCl] were quantitatively measured, and it was found that increasing the luminal [NaCl] resulted in an increase in cell volume. It was also found that NO formation in MD cells could be measured with DAF-2 and that NO production was increased through neuronal NO synthase activation with an increased luminal [NaCl]. An increased NO production will inhibit the vasoconstriction induced by the TGF and at the same time will reduce TGF sensitivity.
Ruisheng Liu; János Pittner; A Erik G Persson
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the American Society of Nephrology : JASN     Volume:  13     ISSN:  1046-6673     ISO Abbreviation:  J. Am. Soc. Nephrol.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-10-24     Completed Date:  2003-04-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9013836     Medline TA:  J Am Soc Nephrol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2688-96     Citation Subset:  IM    
Department of Medical Cell Biology, Uppsala University, Sweden.
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MeSH Terms
Arginine / pharmacology
Cell Count
Fluorescent Dyes
Indicators and Reagents
Juxtaglomerular Apparatus / cytology*,  metabolism*
Microscopy, Confocal
Nitric Oxide / metabolism*
Osmolar Concentration
Sodium Chloride / metabolism*,  pharmacology
Reg. No./Substance:
0/4,5-diaminofluorescein; 0/Fluoresceins; 0/Fluorescent Dyes; 0/Indicators and Reagents; 10102-43-9/Nitric Oxide; 1461-15-0/fluorexon; 2321-07-5/Fluorescein; 74-79-3/Arginine; 7647-14-5/Sodium Chloride

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

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