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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1987-5-15
|
| pubmed:abstractText |
The characteristics of [3H]sulpiride binding to the D2 dopamine receptor in rat striatal membranes were examined under several conditions. In the absence of sodium ions, the specific binding of [3H]sulpiride could not be detected. In the direct binding experiment, at 25 degrees C, the affinity of [3H]sulpiride for D2 receptors was increased in a dose-dependent manner of sodium ions whereas magnesium ions have opposite effects on an affinity of [3H]sulpiride binding. The lowering incubation temperature (4 degrees C) also produced a further increase in affinity of the ligand. Under all conditions, [3H]sulpiride labeled a single homogenous site of the receptor. On the other hand, the result from quantitative analysis of agonist/[3H]sulpiride competition curves indicated an existence of high (RH) and low (RL) affinity states for agonists and the proportion of two-affinity states was modulated by guanosine triphosphate (GTP), magnesium ions and lowering temperatures. GTP, together with sodium ions, caused a full conversion of RH to RL, while an increase in the affinity for agonists with a partial conversion of RL to RH could be induced by magnesium ions at 25 degrees C. At a lower (4 degrees C) temperature, the agonist competition curve indicated an existence of a single agonist low-affinity state (RL) and then, the effects of GTP and magnesium ions in the agonist affinity observed at 25 degrees C were abolished. These results can be incorporated into a two-step, ternary complex model involving an inhibitory guanine nucleotide binding protein for the agonist and antagonist interaction with D2 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Feb
|
| pubmed:issn |
0006-8993
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
3
|
| pubmed:volume |
402
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
331-8
|
| pubmed:dateRevised |
2003-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:3828800-Animals,
pubmed-meshheading:3828800-Binding Sites,
pubmed-meshheading:3828800-Cations, Monovalent,
pubmed-meshheading:3828800-Corpus Striatum,
pubmed-meshheading:3828800-Kinetics,
pubmed-meshheading:3828800-Male,
pubmed-meshheading:3828800-Membranes,
pubmed-meshheading:3828800-Rats,
pubmed-meshheading:3828800-Rats, Inbred Strains,
pubmed-meshheading:3828800-Sulpiride,
pubmed-meshheading:3828800-Tritium
|
| pubmed:year |
1987
|
| pubmed:articleTitle |
The characterization of [3H]sulpiride binding sites in rat striatal membranes.
|
| pubmed:publicationType |
Journal Article
|