title: D4 dopamine receptor-mediated signaling events determined in transfected Chinese hamster ovary cells.
abstract: A Chinese hamster ovary (CHO) cell line stably expressing a recombinant human D4 dopamine receptor made from a synthetic gene has been used to determine potential D4-mediated signaling events. We designed and synthesized a modified gene coding for a human D4 receptor with reduced G + C content but unaltered encoded amino acids. Stable expression of this gene was obtained in two cell lines, inducible expression in CHO lacI cells and constitutive expression in HEK293 cells. In CHO lacI cells induced to express D4 receptors but not in uninduced cells, dopamine and quinpirole inhibit forskolin-stimulated cAMP accumulation and potentiate ATP-stimulated [3H]arachidonic acid release through a mechanism that requires protein kinase C but is unaffected by membrane-soluble cAMP analogs. In addition, D4 receptor activation causes an increase in the rate of extracellular acidification measured by microphysiometry. This response is unaffected by protein kinase C down-regulation but is inhibited by removal of extracellular sodium and inhibitors of NaH-1 exchange, suggesting the involvement of a Na+/H+ exchanger. All responses are blocked by clozapine and are sensitive to pertussis toxin. D4 receptors, like other G(i)/G(o)-linked receptors, mediate multiple signaling events, and the pathways activated are similar to those used by D2 and D3 receptors expressed in similar cells.
authors.affiliation: Upjohn Company, Kalamazoo, Michigan 49001.
authors.forename: C L
authors.initials: CL
authors.lastname: Chio
authors.forename: R F
authors.initials: RF
authors.lastname: Drong
authors.forename: D T
authors.initials: DT
authors.lastname: Riley
authors.forename: G S
authors.initials: GS
authors.lastname: Gill
authors.forename: J L
authors.initials: JL
authors.lastname: Slightom
authors.forename: R M
authors.initials: RM
authors.lastname: Huff
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001483:Base Sequence; D002069:Butaclamol / Q000494:pharmacology; D016466:CHO Cells; D003001:Cloning, Molecular; D003024:Clozapine / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D004247:DNA / Q000138:chemical synthesis; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004873:Ergolines / Q000494:pharmacology; D005813:Genes, Synthetic; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D037342:Pertussis Toxin; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D019257:Quinpirole; D020891:Raclopride; D011954:Receptors, Dopamine / Q000096:biosynthesis / Q000502:physiology*; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D012457:Salicylamides / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: C493599:DRD4 protein, human; D018492:Dopamine Antagonists; D004873:Ergolines; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D011994:Recombinant Proteins; D012457:Salicylamides; D017923:Sodium-Hydrogen Exchangers; D010566:Virulence Factors, Bordetella; D050638:Receptors, Dopamine D4; D019257:Quinpirole; D016718:Arachidonic Acid; D020891:Raclopride; D000584:Amiloride; D004247:DNA; D002069:Butaclamol; D000242:Cyclic AMP; D037342:Pertussis Toxin; D011493:Protein Kinase C; D003024:Clozapine; D006220:Haloperidol; D004298:Dopamine