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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1987-7-30
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pubmed:abstractText |
The selective beta-2 adrenoceptor agonist procaterol produced positive inotropic and chronotropic responses over a concentration range of 1 nM to 0.1 mM in spontaneously beating right atria and in three of seven electrically driven left atria. The pD2 values (right atria, 7.30; left atria, 7.18) were midway between its known affinities at beta-1 and beta-2 adrenoceptors and are evidence that positive inotropic and chronotropic responses involve a minor beta-2 adrenoceptor component. The pKB values for procaterol against (-)-isoproterenol in the right atria (5.59) and left atria (5.29) were consistent with its affinity for beta-1 adrenoceptors and suggest that these are responsible primarily for positive inotropic and chronotropic responses. Receptor binding studies in right atrial homogenates showed that [125I]cyanopindolol binding was saturable (KD = 36.2 pM, maximal density of binding sites = 49.2 fmol mg-1 protein) and stereoselective with respect to the isomers of propranolol. Competition binding curves for the beta-1 adrenoceptor antagonist CGP 20712A and beta-2 selective antagonist ICI 118,551 against [125I]cyanopindolol binding were resolved into two components using iterative curve fitting techniques. Binding sites with the characteristics of beta-1 and beta-2 adrenoceptors were present in the proportions of approximately 75 to 25%. These studies indicate either that the beta-1 adrenoceptor is coupled more efficiently to the positive inotropic and chronotropic response than the beta-2 adrenoceptor or that a proportion of the beta-2 adrenoceptors subserve other functions.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/CGP 20712A,
http://linkedlifedata.com/resource/pubmed/chemical/Ethanolamines,
http://linkedlifedata.com/resource/pubmed/chemical/ICI 118551,
http://linkedlifedata.com/resource/pubmed/chemical/Imidazoles,
http://linkedlifedata.com/resource/pubmed/chemical/Isoproterenol,
http://linkedlifedata.com/resource/pubmed/chemical/Pindolol,
http://linkedlifedata.com/resource/pubmed/chemical/Procaterol,
http://linkedlifedata.com/resource/pubmed/chemical/Propanolamines,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, beta,
http://linkedlifedata.com/resource/pubmed/chemical/cyanopindolol
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pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0022-3565
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
241
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1041-7
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:3037064-Animals,
pubmed-meshheading:3037064-Electric Stimulation,
pubmed-meshheading:3037064-Ethanolamines,
pubmed-meshheading:3037064-Female,
pubmed-meshheading:3037064-Guinea Pigs,
pubmed-meshheading:3037064-Heart Atria,
pubmed-meshheading:3037064-Heart Rate,
pubmed-meshheading:3037064-Imidazoles,
pubmed-meshheading:3037064-Isoproterenol,
pubmed-meshheading:3037064-Kinetics,
pubmed-meshheading:3037064-Myocardial Contraction,
pubmed-meshheading:3037064-Myocardium,
pubmed-meshheading:3037064-Pindolol,
pubmed-meshheading:3037064-Procaterol,
pubmed-meshheading:3037064-Propanolamines,
pubmed-meshheading:3037064-Receptors, Adrenergic, beta,
pubmed-meshheading:3037064-Stimulation, Chemical,
pubmed-meshheading:3037064-Uterine Contraction,
pubmed-meshheading:3037064-Uterus
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pubmed:year |
1987
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pubmed:articleTitle |
Characterization of beta-1 and beta-2 adrenoceptors in guinea pig atrium: functional and receptor binding studies.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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