Figure 3. Differential effects of PG01042, PG01037, and VK4-116 on the locomotor activation induced by D₁R and D₂-like receptor agonists in reserpinized mice.

Mice were administered reserpine (5 mg/kg, s.c.) 20 h before administration of the D₁R agonist SKF 81297 (SKF; 5 mg/kg, i.p.), the D₂-like receptor agonist pramipexole (PMX; 1, 3 or 10 mg/kg, i.p.), or both, without (a) or with (b) previous administration (15 min before) of the D₃R ligands PG01042 (10 mg/kg, i.p.), PG01037 (30 mg/kg, i.p.) or VK4-116 (10 mg/kg, i.p.). Values are mean ± S.E.M. (n = 5–18) and are expressed as the average of the transformed counts (squared root) obtained from the 10 min-periods recorded for 1 h. In a, **, *** and ****: p < 0.01, p < 0.001 and p < 0.0001 versus vehicle-treated animals (represented by the dotted line), respectively; ###: p < 0.001 versus SKF (one-way ANOVA followed by Tukey’s post hoc comparisons) (one-way ANOVA followed by Tukey’s post hoc comparisons). In b, *, **, *** and ****: p < 0.05, p < 0.01, p < 0.001 and p < 0.0001 versus respective saline-treated animals, respectively.