The role of D1-D2 receptor hetero-dimerization in the mechanism of action of clozapine.
Clozapine is effective although still not perfect drug used to treat schizophrenia. The precise mechanism of its action is not known. Here we show that there are two binding sites for clozapine at the dopamine D1 and D2 receptors, and the affinity of D1R strongly depended on whether the receptor was present alone or together with D2R (or its genetic variant D2Ser311Cys) in the cell membrane, pointing to the role of receptor hetero-dimerization in the observed phenomenon. The use of fluorescence resonance energy transfer (FRET) technology, observed via fluorescence lifetime microscopy of the single cell, indicated that low concentration of clozapine (10(-9) M), sufficient to saturate the high affinity site, uncoupled the D1R-D2R hetero-dimers. Therefore it has been concluded that clozapine might antagonize the effect of concomitant stimulation of both dopamine receptors, which has been shown previously to enhance the formation of hetero-dimers and to stimulate the calcium signaling pathway.
Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
Agata
A
Faron-Górecka
Andrzej
A
Górecki
Maciej
M
Kuśmider
Zygmunt
Z
Wasylewski
Marta
M
Dziedzicka-Wasylewska
D014150:Antipsychotic Agents / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites / Q000187:drug effects; D001667:Binding, Competitive / Q000187:drug effects; D002461:Cell Line, Transformed; D003024:Clozapine / Q000494:pharmacology*; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D017354:Point Mutation / Q000235:genetics; D017447:Receptors, Dopamine D1 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D014162:Transfection / Q000379:methods; D014316:Tritium / Q000378:metabolism
D014150:Antipsychotic Agents; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D011993:Recombinant Fusion Proteins; D014316:Tritium; D049452:Green Fluorescent Proteins; D003024:Clozapine