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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1989-4-26
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pubmed:abstractText |
We compared the pharmacological properties of the alpha 2-adrenergic radioligand [3H]idazoxan with those of [3H]rauwolscine in rat and [3H]yohimbine in human renal cortical membranes. The density of "specific" [3H]idazoxan binding sites (defined by 100 microM tolazoline) was twice as high as that of [3H]rauwolscine in rat kidney and four times as high as that of [3H]yohimbine in human kidney. A variety of structurally different drugs fully competed for specific [3H]rauwolscine and [3H]yohimbine binding, with affinities appropriate for the interaction with alpha 2-adrenergic receptors. Specific [3H]idazoxan binding, however, was only partially competed for by the catecholamines epinephrine and norepinephrine in both tissues. Thus, [3H]idazoxan labels both alpha 2-adrenergic receptors and a nonadrenergic site. Clonidine, B-HT 920, moxonidine, phentolamine, prazosin, yohimbine, dopamine, and serotonin also could not compete for this site. However, UK 14,304, guanabenz, indanidine, tolazoline, oxymetazoline, and SK&F 104,078 competed for the additional [3H]idazoxan sites with affinities similar to those at alpha 2-adrenergic receptors. [3H]idazoxan binding substantially in excess of [3H]rauwolscine or [3H]yohimbine binding was also found in human platelets, myometrium, and erythroleukemia (HEL) cells but not in three cell lines lacking alpha 2-receptors (MDCK, BC3H1, and Jurkat cells). Although we have been unsuccessful thus far in defining the precise nature of the additional [3H]idazoxan binding sites, we hypothesize that these sites may be closely affiliated with alpha 2-adrenergic receptors but clearly distinct from the catecholamine binding site of the receptor. The results indicate that care must be taken in the use of [3H]idazoxan or drugs that are recognized at its nonadrenergic site when studying alpha 2-adrenergic effects and receptor subtypes.
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pubmed:grant | |
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-Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/Dioxanes,
http://linkedlifedata.com/resource/pubmed/chemical/Dioxins,
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Idazoxan,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, alpha,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium,
http://linkedlifedata.com/resource/pubmed/chemical/Yohimbine
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0026-895X
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
35
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
324-30
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:2564631-Adrenergic alpha-Antagonists,
pubmed-meshheading:2564631-Animals,
pubmed-meshheading:2564631-Binding Sites,
pubmed-meshheading:2564631-Dioxanes,
pubmed-meshheading:2564631-Dioxins,
pubmed-meshheading:2564631-Guanosine Triphosphate,
pubmed-meshheading:2564631-Humans,
pubmed-meshheading:2564631-Idazoxan,
pubmed-meshheading:2564631-Kidney Cortex,
pubmed-meshheading:2564631-Male,
pubmed-meshheading:2564631-Rats,
pubmed-meshheading:2564631-Rats, Inbred Strains,
pubmed-meshheading:2564631-Receptors, Adrenergic, alpha,
pubmed-meshheading:2564631-Sodium,
pubmed-meshheading:2564631-Yohimbine
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pubmed:year |
1989
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pubmed:articleTitle |
[3H]idazoxan and some other alpha 2-adrenergic drugs also bind with high affinity to a nonadrenergic site.
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pubmed:affiliation |
Department of Pharmacology, University of California San Diego, La Jolla 92093.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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