title: Expression and characterization of the rat D3 dopamine receptor: pharmacologic properties and development of antibodies.
abstract: A baculovirus expression system provided an enriched source of biologically and immunologically active D3 dopamine receptors. Receptors expressed in Spodoptera frugiperda insect (Sf9) cells at a density of 5 to 15 pmol/mg of protein displayed high affinity for the antagonists, eticlopride, fluphenazine and spiroperidol, and the agonist, N-propylnorapomorphine. The binding of agonists was not sensitive to GTP. Antisera raised against synthetic peptides in the third intracellular loop of the D3 dopamine receptor immunoprecipitated binding sites for (S)-3-[125I]-iodo-2-hydroxy-5,6-dimethoxy-N-[(1-ethyl-2-pyrrolidinyl)- methyl]-benzamide from solubilized extracts of infected Sf9 cells and detergent extracts of rat caudate. These antisera specifically recognized a single band on immunoblots of Sf9 cells infected with recombinant D3 baculovirus. Both the immunoprecipitation and immunoblot reactions were blocked by preincubation of the antisera with the immunization peptide. These results suggest that the D3 receptor protein is expressed in rat brain.
authors.affiliation: Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia.
authors.forename: V A
authors.initials: VA
authors.lastname: Boundy
authors.forename: R R
authors.initials: RR
authors.lastname: Luedtke
authors.forename: A L
authors.initials: AL
authors.lastname: Gallitano
authors.forename: J E
authors.initials: JE
authors.lastname: Smith
authors.forename: T M
authors.initials: TM
authors.lastname: Filtz
authors.forename: R G
authors.initials: RG
authors.lastname: Kallen
authors.forename: P B
authors.initials: PB
authors.lastname: Molinoff
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D001665:Binding Sites; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007106:Immune Sera / Q000276:immunology*; D008969:Molecular Sequence Data; D009036:Moths; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D051381:Rats; D011954:Receptors, Dopamine / Q000032:analysis* / Q000187:drug effects / Q000276:immunology; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D011994:Recombinant Proteins / Q000032:analysis; D012457:Salicylamides / Q000378:metabolism
chemical_list: C493593:DRD3 protein, human; C493595:Drd3 protein, rat; D007106:Immune Sera; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D011994:Recombinant Proteins; D012457:Salicylamides; C064246:NCQ 298