Document Detail


Role of blood pressure in regulating Na+/H+ exchange in vascular smooth muscle.
MedLine Citation:
PMID:  8031549     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Na+/H+ exchange differs kinetically in mesenteric arteries from spontaneously hypertensive rats (SHR). Both the maximal transport rate and the sensitivity to [H+]i are greater in SHR than in Wistar Kyoto (WKY) rats. Kinetic changes are not seen in prehypertensive SHR or in SHR rendered normotensive by captopril therapy. Thus, blood pressure affects the properties of Na+/H+ exchange in SHR. To determine whether elevated pressure would have similar effects on the WKY transporter, WKY rats were rendered hypertensive by treatment with deoxycorticosterone acetate (DOCA). Mesenteric arteries from these animals were loaded with the pH-sensitive dye BCECF and Na+/H+ exchange activity was assessed by measuring the Nao-dependent, dimethyl amiloride-sensitive recovery of intracellular pH after acid loading. Treatment with DOCA/salt (two injections of 30 mg of DOCA/kg per week for 4 weeks + 1% NaCl in the drinking water) produced a significant increase in mean arterial pressure (181 +/- 29 v 108.1 +/- 6.2 in DOCA/salt v untreated controls), but had no effect on Na+/H+ exchange. Maximal transport rates for untreated, DOCA/salt-treated, and salt-treated rats were virtually identical (0.088 +/- 0.001, 0.103 +/- 0.011, and 0.093 +/- 0.006 mmol/L H+/sec, respectively. Moreover, the sensitivity of Na+/H+ exchange to internal H+ (ie, the Hill coefficient) was unchanged (n(app) = 4.3, 3.7, and 4.0, respectively). Because elevation in blood pressure produced no significant alterations in the WKY Na+/H+ exchanger, it seems likely that there are strain differences in the exchanger and/or in processes regulating its activity.
Authors:
D R Ellstrom; T W Honeyman; C R Scheid
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of hypertension     Volume:  7     ISSN:  0895-7061     ISO Abbreviation:  Am. J. Hypertens.     Publication Date:  1994 Apr 
Date Detail:
Created Date:  1994-08-12     Completed Date:  1994-08-12     Revised Date:  2009-02-24    
Medline Journal Info:
Nlm Unique ID:  8803676     Medline TA:  Am J Hypertens     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  340-5     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Massachusetts Medical School, Worcester 01655.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure / physiology*
Desoxycorticosterone
Fluoresceins
Fluorescent Dyes
Hypertension / chemically induced,  physiopathology
Male
Mesenteric Arteries
Muscle, Smooth, Vascular / metabolism*
Rats
Rats, Inbred SHR
Rats, Inbred WKY
Sodium Chloride
Sodium-Hydrogen Antiporter / metabolism*
Grant Support
ID/Acronym/Agency:
HL41188/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Fluoresceins; 0/Fluorescent Dyes; 0/Sodium-Hydrogen Antiporter; 64-85-7/Desoxycorticosterone; 7647-14-5/Sodium Chloride; 85138-49-4/2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein

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


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