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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1994-5-19
|
| pubmed:abstractText |
We previously reported that dopamine (DA) inhibited the release of human placental lactogen (hPL) from human placental cells. We also demonstrated the presence of D2-dopamine receptors in membrane preparations of human term placenta. The aim of the present study was to characterize these D2 receptors on freshly isolated human trophoblastic cells. The binding of [3H]-spiperone to these cells showed a curvilinear Scatchard plot suggesting the presence of two classes of binding sites (Kd1 = 1.26nM; Kd2 = 44.3nM). Competition experiments showed the following inhibitory binding potencies: serotonin-2 (5-HT2) > or = D2 >>> alpha-adrenergic, beta-adrenergic, D1-dopamine, thus suggesting the presence of 5-HT2 binding sites. We have examined this possibility by blocking [3H]-spiperone binding to 5-HT2 receptors in the presence of 50nM ketanserin, a selective antagonist of 5-HT2 sites. Under this condition, the linear Scatchard plot obtained suggested a single population of homogeneous binding sites for [3H]-spiperone with a Kd of 0.55nM. To further characterize placental D2 receptors we conducted binding experiments with [3H]-raclopride, an more selective D2 antagonist. The linear Scatchard plot obtained with this ligand suggested one class of binding sites for [3H]-raclopride (Kd = 6nM) with the following inhibitory potencies: D2 >>> beta-adrenergic >> 5-HT2, D1, alpha-adrenergic. These results suggest an important paracrine function for DA in human placenta and show for the first time that [3H]-spiperone binds putative 5-HT2 receptors in human placenta.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jan
|
| pubmed:issn |
0197-5110
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
14
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
11-22
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1994
|
| pubmed:articleTitle |
Labelling of D2-dopaminergic and 5-HT2-serotonergic binding sites in human trophoblastic cells using [3H]-spiperone.
|
| pubmed:affiliation |
Departement of Obstetrics and Gynecology, Faculty of Medecine, University of Montreal, Quebec, Canada.
|
| pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
|