title: Pharmacological analysis of a dopamine D(2Short):G(alphao) fusion protein expressed in Sf9 cells.
abstract: A dopamine D(2Short) receptor:G(alphao) fusion protein was expressed in Sf9 cells using the baculovirus expression system. [(3)H]Spiperone bound to D(2Short):G(alphao) with a pK(d) approximately 10. Dopamine stimulated the binding of [(35)S]guanosine-5'-O-(3-thio)triphosphate (GTPgammaS) to D(2Short):G(alphao) expressed with Gbeta(1)gamma(2) (E(max)>460%; pEC(50) 5.43+/-0.06). Most of the putative D(2) antagonists behaved as inverse agonists (suppressing basal [(35)S]GTPgammaS binding) at D(2Short):G(alphao)/Gbeta(1)gamma(2) although (-)-sulpiride and ziprasidone were neutral antagonists. Competition of [(3)H]spiperone binding by dopamine and 10,11-dihydroxy-N-n-propylnorapomorphine revealed two binding sites of different affinities, even in the presence of GTP (100 micro M). The D(2Short):G(alphao) fusion protein is therefore a good model for characterising D(2) receptors.
authors.affiliation: School of Animal and Microbial Sciences, University of Reading, Whiteknights, RG6 6AJ, Reading, UK.
authors.forename: Lucien
authors.initials: L
authors.lastname: Gazi
authors.forename: Thierry
authors.initials: T
authors.lastname: Wurch
authors.forename: Juan F
authors.initials: JF
authors.lastname: Lopéz-Giménez
authors.forename: Petrus J
authors.initials: PJ
authors.lastname: Pauwels
authors.forename: Philip G
authors.initials: PG
authors.lastname: Strange
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016367:Baculoviridae; D001665:Binding Sites; D001667:Binding, Competitive; D002460:Cell Line; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004347:Drug Interactions; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D008024:Ligands; D017448:Receptors, Dopamine D2 / Q000032:analysis / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000378:metabolism*; D013134:Spiperone / Q000494:pharmacology; D018411:Spodoptera
chemical_list: C425777:10,11-dihydroxy-N-n-propylnorapomorphine; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D008024:Ligands; D017448:Receptors, Dopamine D2; D011993:Recombinant Fusion Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D013134:Spiperone; D019204:GTP-Binding Proteins; D001058:Apomorphine