TY - JOUR T1 - Signaling pathways leading to phosphorylation of Akt and GSK-3β by activation of cloned human and cerebral rat D2 and D3 receptors JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.110.065409 SP - mol.110.065409 AU - Clotilde MANNOURY LA COUR AU - Marie-Josephe SALLES AU - Valerie PASTEAU AU - Mark J MILLAN Y1 - 2010/10/15 UR - http://molpharm.aspetjournals.org/content/early/2010/10/15/mol.110.065409.abstract N2 - Though dopamine (DA) regulates the serine/threonine kinase, Akt, and its downstream substrate, glycogen synthase kinase-3β (GSK-3β), the direct influence of dopaminergic receptors remains poorly characterised. Short-term incubation of CHO-expressed human (h)D2L and hD3 receptors with DA (maximal effect, 5-10 min) phosphorylated Akt (Thr308 and Ser473) and GSK-3β (Ser9), actions blocked by the selective D2 and D3 antagonists, L741,626 and S33084, respectively. Similar findings were acquired with the specific D2/D3 receptor agonist, quinelorane, which also enhanced (10 minutes after administration) levels of p-Akt and p-GSK-3β in rat nucleus accumbens, an action blocked by the D2/D3 receptor antagonist, raclopride. Akt and GSK-3β phosphorylation mediated via CHO-expressed hD2L and hD3 receptors was prevented by pertussis toxin, and by inhibitors of insulin-like growth factor-1 receptors as well as phosphatidylinositol 3-kinase and Src. Likewise, chelation of intracellular Ca2+ and interference with an "atypical" phorbol ester-insensitive Protein Kinase C abolished recruitment of Akt and GSK 3β. Inactivation of Protein Kinase Cμ(PKC) blocked Akt and GSK-3β phosphorylation at hD2L receptors. However, blockade of conventional PKC isoforms attenuated the actions of DA at hD3 receptors only. Further, phospholipase C (PLC), calmodulin and Akt inhibitors abolished DA-induced GSK-3β phosphorylation by hD3 receptors, whereas phosphorylation by hD2L receptors partially involved both Akt and ERK1/2. In conclusion, at both hD2L and hD3 receptors, DA elicited a Gi/o- and Ca2+/calmodulin-dependent phosphorylation of Akt and GSK-3β via transactivation of insulin-like growth factor 1 receptor. However, significant differences were seen as regards the involvement of PLC, calmodulin and ERK1/2. ER -