Figure 10.

Reversal of amphetamine-induced phosphorylation of GluR1-Ser845, ERK1/2-Thr202/Tyr204, and rpS6-Ser235/23 by donepezil in the striatum of conditional D₁R-γ₇ KO mice and WT littermates. Representative immunoblots and densitometric analysis of phosphorylated and total protein levels in striatal homogenates of Gng7^fl/flD₁Cre⁺ and respective Gng7^fl/fl WT mice. Mice were pretreated with donepezil (3 mg/kg) or saline 10 min before receiving an injection of amphetamine (10 mg/kg) or saline. Striatal tissues were collected 20 min after the amphetamine injection. Each column represents a normalized ratio (fold-change) relative to total protein and to controls (Gng7^fl/fl saline). The relative levels of GluR1, ERK1/2, and rpS6 were normalized to β-actin. Samples derive from the same experiment and the blots were processed in parallel. A loading control was included in each gel and was used to normalize data across multiple blots. Amphetamine increased the phosphorylation state of GluR1-Ser845, ERK2-Thr202/Tyr204, and rpS6-Ser235/23 independently of genotype. Donepezil pretreatment significantly reduced the amphetamine-induced phosphorylation of GluR1-Ser845 (A) and rpS6-Ser235/23 (C) in both Gng7^fl/flD₁Cre⁺ and Gng7^fl/fl WT mice (three-way ANOVA and Tukey's post hoc: “pretreatment × treatment” interaction, ***p < 0.001 saline-amphetamine vs saline-saline; ^###p < 0.001 donepezil-amphetamine vs saline-amphetamine). Donepezil pretreatment reduced ERK2-Thr202/Tyr204 phosphorylation (B) both at baseline and after amphetamine treatment. Total levels of GluR1, ERK, and rpS6 proteins were not affected by amphetamine or donepezil treatment. Data are mean ± SEM. n = 7-9 mice/group.