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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
1994-4-20
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pubmed:abstractText |
Potential desensitization of brain nicotinic receptors was studied using a [3H]dopamine release assay. Nicotine-stimulated [3H]dopamine release from mouse striatal synaptosomes was concentration-dependent with an EC50 of 0.33 +/- 0.13 microM and a Hill coefficient of 1.44 +/- 0.18. Desensitization by activating concentrations of nicotine had a similar EC50 and a half-time of 35 s. Concentrations of nicotine that evoked little release also induced a concentration-dependent desensitization (EC50 = 6.9 +/- 3.6 nM, t1/2 = 1.6-2.0 min, nH = 1.02 +/- 0.01). Both types of desensitization produced a maximum 75% decrease in [3H]dopamine release. Recovery from desensitization after exposure to low or activating concentrations of nicotine was time-dependent with half-times of 6.1 min and 12.4 min, respectively. Constants determined for binding of [3H]nicotine to striatal membrane at 22 degrees C included a KD of 3.7 +/- 0.5 nM, Bmax of 67.5 +/- 2.2 fmol/mg, and Hill coefficient of 1.07 +/- 0.06. Association of nicotine with membrane binding sites was biphasic with half-times of 9 s and 1.8 min. The fast rate process contributed 37% of the total reaction. Dissociation was a uniphasic process with a half-time of 1.6 min. Comparison of constants determined by the release and binding assays indicated that the [3H]-nicotine binding site could be the presynaptic receptor involved in [3H]dopamine release in mouse striatal synaptosomes.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0022-3042
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
62
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1390-8
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:8133269-Animals,
pubmed-meshheading:8133269-Corpus Striatum,
pubmed-meshheading:8133269-Dopamine,
pubmed-meshheading:8133269-Dose-Response Relationship, Drug,
pubmed-meshheading:8133269-Drug Tolerance,
pubmed-meshheading:8133269-Female,
pubmed-meshheading:8133269-Kinetics,
pubmed-meshheading:8133269-Mice,
pubmed-meshheading:8133269-Mice, Inbred C57BL,
pubmed-meshheading:8133269-Nicotine,
pubmed-meshheading:8133269-Receptors, Nicotinic,
pubmed-meshheading:8133269-Synaptosomes,
pubmed-meshheading:8133269-Tritium
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pubmed:year |
1994
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pubmed:articleTitle |
Desensitization of nicotine-stimulated [3H]dopamine release from mouse striatal synaptosomes.
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pubmed:affiliation |
Institute for Behavioral Genetics, University of Colorado, Boulder.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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