title: Regulation of the phosphorylation of the dopamine- and cAMP-regulated phosphoprotein of 32 kDa in vivo by dopamine D1, dopamine D2, and adenosine A2A receptors.
abstract: Dopamine D(1), dopamine D(2), and adenosine A(2A) receptors are highly expressed in striatal medium-sized spiny neurons. We have examined, in vivo, the influence of these receptors on the state of phosphorylation of the dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32). DARPP-32 is a potent endogenous inhibitor of protein phosphatase-1, which plays an obligatory role in dopaminergic transmission. A dose-dependent increase in the state of phosphorylation of DARPP-32 occurred in mouse striatum after systemic administration of the D(2) receptor antagonist eticlopride (0.1-2.0 mg/kg). This effect was abolished in mice in which the gene coding for the adenosine A(2A) receptor was disrupted by homologous recombination. A reduction was also observed in mice that had been pretreated with the selective A(2A) receptor antagonist SCH 58261 (10 mg/kg). The eticlopride-induced increase in DARPP-32 phosphorylation was also decreased by pretreatment with the D(1) receptor antagonist SCH 23390 (0.125 and 0.25 mg/kg) and completely reversed by combined pretreatment with SCH 23390 (0.25 mg/kg) plus SCH 58261 (10 mg/kg). SCH 23390, but not SCH 58261, abolished the increase in DARPP-32 caused by cocaine (15 mg/kg). The results indicate that, in vivo, the state of phosphorylation of DARPP-32 and, by implication, the activity of protein phosphatase-1 are regulated by tonic activation of D(1), D(2), and A(2A) receptors. The results also underscore the fact that the adenosine system plays a role in the generation of responses to dopamine D(2) antagonists in vivo.
authors.affiliation: Department of Physiology, Karolinska Institutet, S-171 77 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Svenningsson
authors.forename: M
authors.initials: M
authors.lastname: Lindskog
authors.forename: C
authors.initials: C
authors.lastname: Ledent
authors.forename: M
authors.initials: M
authors.lastname: Parmentier
authors.forename: P
authors.initials: P
authors.lastname: Greengard
authors.forename: B B
authors.initials: BB
authors.lastname: Fredholm
authors.forename: G
authors.initials: G
authors.lastname: Fisone
mesh_terms: D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D011743:Pyrimidines / Q000494:pharmacology; D043705:Receptor, Adenosine A2A; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D012457:Salicylamides / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology
chemical_list: C098657:5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine; D001552:Benzazepines; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011743:Pyrimidines; D043705:Receptor, Adenosine A2A; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D018047:Receptors, Purinergic P1; D012457:Salicylamides; D014230:Triazoles; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D003042:Cocaine; C045989:eticlopride; D004298:Dopamine