title: Stable expression of human D3 dopamine receptors in GH4C1 pituitary cells.
abstract: Human D3 dopamine receptor DNA was stably transfected into GH4C1 pituitary cells. Displacement of iodosulpiride binding in hD3 transfected cells (Kd = 0.3 nM, Bmax = 89 fmol/mg protein) by dopaminergic ligands was indistinguishable from that of hD3 receptors in CHO cells. Only two clonal cell lines exhibited weak GppNHp-dependent shifts in [3H]N-0437 binding, and these were used for functional assays. Neither arachidonic acid metabolism, cAMP levels, inositol phosphate turnover, intracellular calcium, or potassium currents were consistently affected by dopamine (1-10 microM). The paucity of responses indicates that human D3 receptors do not couple efficiently to these second messengers in GH4C1 cells.
authors.affiliation: Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, UK.
authors.forename: G R
authors.initials: GR
authors.lastname: Seabrook
authors.forename: S
authors.initials: S
authors.lastname: Patel
authors.forename: R
authors.initials: R
authors.lastname: Marwood
authors.forename: F
authors.initials: F
authors.lastname: Emms
authors.forename: M R
authors.initials: MR
authors.lastname: Knowles
authors.forename: S B
authors.initials: SB
authors.lastname: Freedman
authors.forename: G
authors.initials: G
authors.lastname: McAllister
mesh_terms: D001095:Arachidonic Acids / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D008024:Ligands; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D011954:Receptors, Dopamine / Q000096:biosynthesis* / Q000235:genetics; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D014162:Transfection
chemical_list: D001095:Arachidonic Acids; C493593:DRD3 protein, human; D007295:Inositol Phosphates; D008024:Ligands; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D006160:Guanosine Triphosphate; D000242:Cyclic AMP; D011188:Potassium; D002118:Calcium; D004298:Dopamine