Source:http://linkedlifedata.com/resource/pubmed/id/10321720
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
16
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pubmed:dateCreated |
1999-5-26
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pubmed:abstractText |
Alpha2-adrenoceptor (alpha2-AR)-regulated binding of the labelled GTP analog, guanosine 5'-O-(3-[35S]thiotriphosphate) ([35S]GTPgammaS), to guanine-nucleotide-binding proteins (G proteins) was studied in human platelet membranes. Under optimal conditions, the potent alpha2-AR agonist, 5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline (UK 14304), increased the binding of [35S]GTPgammaS up to approximately 1.8 fold, with half-maximal increase at 60 nM and was competitively inhibited by the alpha2-AR antagonist Rauwolscine. The actions of both UK 14304 and Rauwolscine were modulated by monovalent and divalent cation levels, as well as by the concentrations of GDP. [35S]GTPgammaS binding induced by UK 14304 had a Kd value of 4.5 +/- 0.3 nM and a Bmax value of 4.15 +/- 0.40 pmol/mg protein. The rank order of potencies of adrenergic ligands tested in stimulating [3S]GTPgammaS binding and inhibiting forskolin-stimulated c-AMP accumulation was UK 14304> Guanabenz acetate> Oxymetazoline hydrochloride> B-HT 920 dihydrochloride> p-Aminoclonidine hydrochloride> Clonidine hydrochloride. The data presented indicate that enhancement of [35S]GTPgammaS binding by alpha2-AR in human platelet membranes provides a simple functional measure for receptor activation and can be used for determination of potencies and efficacies of ligands at the alpha2-AR.
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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/Adrenergic alpha-Agonists,
http://linkedlifedata.com/resource/pubmed/chemical/Cyclic AMP,
http://linkedlifedata.com/resource/pubmed/chemical/GTP-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine 5'-O-(3-Thiotriphosphate),
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Diphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Quinoxalines,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Chloride,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfur Radioisotopes,
http://linkedlifedata.com/resource/pubmed/chemical/brimonidine
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pubmed:status |
MEDLINE
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pubmed:issn |
0024-3205
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
64
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1403-13
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pubmed:dateRevised |
2004-11-17
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pubmed:meshHeading |
pubmed-meshheading:10321720-Adrenergic alpha-Agonists,
pubmed-meshheading:10321720-Blood Platelets,
pubmed-meshheading:10321720-Cell Membrane,
pubmed-meshheading:10321720-Cyclic AMP,
pubmed-meshheading:10321720-GTP-Binding Proteins,
pubmed-meshheading:10321720-Guanosine 5'-O-(3-Thiotriphosphate),
pubmed-meshheading:10321720-Guanosine Diphosphate,
pubmed-meshheading:10321720-Humans,
pubmed-meshheading:10321720-Kinetics,
pubmed-meshheading:10321720-Quinoxalines,
pubmed-meshheading:10321720-Sodium Chloride,
pubmed-meshheading:10321720-Sulfur Radioisotopes
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pubmed:year |
1999
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pubmed:articleTitle |
Alpha2-adrenergic agonist modulation of [35S]GTPgammaS binding to guanine-nucleotide-binding-proteins in human platelet membranes.
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pubmed:affiliation |
Department of Clinical and Experimental Medicine, University of Ferrara, Italy.
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pubmed:publicationType |
Journal Article
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