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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
10
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pubmed:dateCreated |
1998-6-23
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pubmed:abstractText |
Alpha1-adrenoceptor (alpha1-AR) stimulation increases sarcolemmal Na+-H+ exchanger (NHE) activity. The present study was designed to determine the role(s) of alpha1-AR subtype(s) in mediating this response. As an index of NHE activity, acid efflux rates (JHs) were determined in single rat ventricular myocytes loaded with the pH-sensitive fluoroprobe carboxy-seminaphthorhodafluor-1 after 2 consecutive intracellular acid pulses in bicarbonate-free medium. JH at pHi 6.90 did not change significantly during the second pulse relative to the first in control cells but increased in a dose-dependent manner when the second pulse occurred in the presence of phenylephrine (nonselective alpha1-AR agonist) or A61603 (alpha1A-AR-selective agonist), with EC50 values of 1.24 micromol/L and 3.6 nmol/L, respectively (both agonists given together with 1 micromol/L atenolol). Stimulation of NHE activity by 10 micromol/L phenylephrine was inhibited in a dose-dependent manner by the competitive antagonists prazosin, WB4101, and 5-methylurapidil, with IC50 values of 12, 32, and 149 nmol/L, respectively. Analyses of the relative EC50 and IC50 values obtained (and Ki values estimated from the antagonist IC50s) in relation to the relative potencies of these agents at native rat alpha1-AR subtypes and their relative affinities for recombinant rat alpha1-ARs suggest that alpha1-adrenergic stimulation of sarcolemmal NHE activity is likely to be mediated selectively by the alpha1A-AR.
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pubmed:grant |
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/(2-(2',6'-dimethoxy)phenoxyethylamin...,
http://linkedlifedata.com/resource/pubmed/chemical/5-methylurapidil,
http://linkedlifedata.com/resource/pubmed/chemical/A 61603,
http://linkedlifedata.com/resource/pubmed/chemical/ADRA1A protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Adra1a protein, rat,
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Agonists,
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/Clonidine,
http://linkedlifedata.com/resource/pubmed/chemical/Dioxanes,
http://linkedlifedata.com/resource/pubmed/chemical/Imidazoles,
http://linkedlifedata.com/resource/pubmed/chemical/Phenylephrine,
http://linkedlifedata.com/resource/pubmed/chemical/Piperazines,
http://linkedlifedata.com/resource/pubmed/chemical/Prazosin,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, alpha-1,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium-Hydrogen Antiporter,
http://linkedlifedata.com/resource/pubmed/chemical/Tetrahydronaphthalenes,
http://linkedlifedata.com/resource/pubmed/chemical/chlorethylclonidine
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pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0009-7330
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
82
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1078-85
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pubmed:dateRevised |
2010-11-18
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pubmed:meshHeading |
pubmed-meshheading:9622160-Adrenergic alpha-Agonists,
pubmed-meshheading:9622160-Adrenergic alpha-Antagonists,
pubmed-meshheading:9622160-Animals,
pubmed-meshheading:9622160-Cattle,
pubmed-meshheading:9622160-Clonidine,
pubmed-meshheading:9622160-Dioxanes,
pubmed-meshheading:9622160-Heart Ventricles,
pubmed-meshheading:9622160-Humans,
pubmed-meshheading:9622160-Imidazoles,
pubmed-meshheading:9622160-Kinetics,
pubmed-meshheading:9622160-Myocardium,
pubmed-meshheading:9622160-Phenylephrine,
pubmed-meshheading:9622160-Piperazines,
pubmed-meshheading:9622160-Prazosin,
pubmed-meshheading:9622160-Rats,
pubmed-meshheading:9622160-Receptors, Adrenergic, alpha-1,
pubmed-meshheading:9622160-Sarcolemma,
pubmed-meshheading:9622160-Sodium-Hydrogen Antiporter,
pubmed-meshheading:9622160-Tetrahydronaphthalenes
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pubmed:year |
1998
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pubmed:articleTitle |
Alpha1-adrenergic stimulation of sarcolemmal Na+-H+ exchanger activity in rat ventricular myocytes: evidence for selective mediation by the alpha1A-adrenoceptor subtype.
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pubmed:affiliation |
Cardiovascular Research, The Rayne Institute, St Thomas' Hospital, London, UK.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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