title: Differential effects of amisulpride and haloperidol on dopamine D2 receptor-mediated signaling in SH-SY5Y cells.
abstract: Dopamine D(2) receptors (D(2)R) are the primary target of antipsychotic drugs and have been shown to regulate Akt/glycogen synthase kinase-3β (GSK-3β) signaling through scaffolding protein β-arrestin 2. Amisulpride, an atypical antipsychotic drug, and haloperidol, a typical antipsychotic drug, are both potent D(2)R antagonists, but their therapeutic effects differ. In the present study, we compared the effects of amisulpride and haloperidol on the β-arrestin 2-mediated Akt/GSK-3β pathway in SH-SY5Y cells. To determine whether these drugs affected neuronal morphology in SH-SY5Y cells, we investigated the effects of amisulpride and haloperidol on neurite outgrowth using immunostaining. We examined the effects of these drugs on Akt and GSK-3β and its well-known downstream regulators, cAMP response element-binding protein (CREB), brain-derived neurotrophic factor (BDNF), and Bcl-2 levels using Western blot analysis. Amisulpride, but not haloperidol, was found to enhance neurite outgrowth. Small interfering RNA (siRNA) for β-arrestin 2 knockdown blocked the increase in amisulpride-induced neurite outgrowth. Furthermore, amisulpride increased the levels of Akt and GSK-3β phosphorylation, while haloperidol had no effect. The elevation of Akt phosphorylation induced by amisulpride was reduced by β-arrestin 2 siRNA. Moreover, amisulpride effectively increased the levels of phospho-CREB, BDNF, and Bcl-2. However, haloperidol had no effect on the levels of these proteins. Additionally, wortmannin, a phosphatidylinositol 3-kinase (PI3 K) inhibitor, blocked the stimulatory effect of amisulpride on phosphorylated Akt. Together, these results suggest that regulation of the β-arrestin 2-dependent pathway via blockade of the D(2)R in SH-SY5Y cells is one mechanism underlying the neuroprotective effect of amisulpride, but not haloperidol.
authors.affiliation: Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Park
authors.forename: Mi Kyoung
authors.initials: MK
authors.lastname: Seo
authors.forename: Hye Yeon
authors.initials: HY
authors.lastname: Cho
authors.forename: Jung Goo
authors.initials: JG
authors.lastname: Lee
authors.forename: Bong Ju
authors.initials: BJ
authors.lastname: Lee
authors.forename: Wongi
authors.initials: W
authors.lastname: Seol
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000077582:Amisulpride; D019390:Arrestins / Q000502:physiology; D045744:Cell Line, Tumor; D065127:Dopamine D2 Receptor Antagonists; D006220:Haloperidol / Q000494:pharmacology*; D006801:Humans; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D013469:Sulpiride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605254:ARRB2 protein, human; D019390:Arrestins; D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D013469:Sulpiride; D000077582:Amisulpride; D006220:Haloperidol