Document Detail


Role of chloride in constriction of descending vasa recta by angiotensin II.
MedLine Citation:
PMID:  11353695     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated the dependence of ANG II (10(-8) M)-induced constriction of outer medullary descending vasa recta (OMDVR) on membrane potential (Psim) and chloride ion. ANG II depolarized OMDVR, as measured by fully loading them with the voltage-sensitive dye bis[1,3-dibutylbarbituric acid-(5)] trimethineoxonol [DiBAC(4)(3)] or selectively loading their pericytes. ANG II was also observed to depolarize pericytes from a resting value of -55.6 +/- 2.6 to -26.2 +/- 5.4 mV when measured with gramicidin D-perforated patches. When measured with DiBAC(4)(3) in unstimulated vessels, neither changing extracellular Cl(-) concentration ([Cl(-)]) nor exposure to the chloride channel blocker indanyloxyacetic acid 94 (IAA-94; 30 microM) affected Psim. In contrast, IAA-94 repolarized OMDVR pretreated with ANG II. Neither IAA-94 (30 microM) nor niflumic acid (30 microM, 1 mM) affected the vasoactivity of unstimulated OMDVR, whereas both dilated ANG II-preconstricted vessels. Reduction of extracellular [Cl(-)] from 150 to 30 meq/l enhanced ANG II-induced constriction. Finally, we identified a Cl(-) channel in OMDVR pericytes that is activated by ANG II or by excision into extracellular buffer. We conclude that constriction of OMDVR by ANG II involves pericyte depolarization due, in part, to increased activity of chloride channels.
Authors:
Z Zhang; J M Huang; M R Turner; K L Rhinehart; T L Pallone
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  280     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-05-16     Completed Date:  2001-07-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1878-86     Citation Subset:  IM    
Affiliation:
Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland 21201-1595, USA.
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MeSH Terms
Descriptor/Qualifier:
Angiotensin II / pharmacology*
Animals
Barbiturates
Blood Vessels / drug effects,  physiology
Calibration
Chloride Channels / antagonists & inhibitors,  drug effects,  physiology
Chlorides / pharmacology,  physiology*
Glycolates / pharmacology
Isoxazoles
Kidney Medulla / blood supply*
Membrane Potentials / drug effects
Niflumic Acid / pharmacology
Potassium Chloride / pharmacology
Rats
Rats, Sprague-Dawley
Vasoconstriction* / drug effects
Grant Support
ID/Acronym/Agency:
DK-42495/DK/NIDDK NIH HHS; HL-62220/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Barbiturates; 0/Chloride Channels; 0/Chlorides; 0/Glycolates; 0/Isoxazoles; 110425-49-5/bis(1,3-dibutylbarbiturate)trimethine oxonol; 11128-99-7/Angiotensin II; 4394-00-7/Niflumic Acid; 54197-05-6/MK 473; 7447-40-7/Potassium Chloride

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


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