Functional characterization of the human dopamine D4.2 receptor using vaccinia virus as an expression system.
Recombinant vaccinia viruses harboring the human dopamine D4 receptor cDNA containing two 48 base pair-repeats (D4.2) or the rat dopamine D2 short (D2s) receptor cDNA were used to infect rat-1 fibroblasts. Heterologous expression of both dopamine receptors was demonstrated in binding assays. The affinity constants of these receptors were consistent with values previously reported, including D4.2's higher affinity for the antipsychotic clozapine and raclopride's selectivity for D2 receptors. In the presence of 200 microM 5'-guanylyl-imidodiphosphate (Gpp[NH]p) both receptors exhibited reduced affinities for dopamine. Furthermore, when rat-1 cells were infected with the D2s or the D4.2 recombinant vaccinia viruses and exposed to dopamine agonists, the inhibition of adenylyl cyclase activity was prevented in pertussis toxin-treated cells. This study demonstrates the utility of recombinant receptor-vaccinia viruses in studies of expression, pharmacology and functional coupling of inhibitory G protein-coupled receptors.
Bouvier
C
C
College of Pharmacy, Oregon State University, Corvallis 97331, USA.
Bunzow
J R
JR
Guan
H C
HC
Unteutsch
A
A
Civelli
O
O
Grandy
D K
DK
Van Tol
H H
HH
D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D051381:Rats; D011954:Receptors, Dopamine / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D050638:Receptors, Dopamine D4; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D014616:Vaccinia virus / Q000235:genetics
D000067956:Adenylyl Cyclase Inhibitors; C493599:DRD4 protein, human; C493601:Drd4 protein, rat; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D011994:Recombinant Proteins; D050638:Receptors, Dopamine D4; D000242:Cyclic AMP; D019204:GTP-Binding Proteins