Figure 5.

Administration of the 5-HT₄R agonists to PD mice restored the decrease in cyclic adenosine monophosphate (cAMP) levels in the hippocampus. Mice were given an intraperitoneal injection of prucalopride or velusetrag at a single dose of 3.0 mg/kg in saline containing 1% DMSO or the vehicle only 2 h prior to both extinction training sessions. The hippocampus was collected immediately after the second extinction training. cAMP levels are shown as pmol/mg of trichloroacetic acid (TCA)-precipitated tissue. Data are expressed as the mean ± SEM; n = 7–8. * p < 0.05 and ** p < 0.01 vs. control + vehicle, ⁺ p < 0.05 and ⁺⁺ p < 0.01 vs. MPTP + vehicle (one-way ANOVA followed by Tukey’s post-hoc test).