Locomotor activity induced by quinpirole and haloperidol. (A) Quinpirole effect on locomotor activity in WT, D2S−/−, and D2L−/− mice [genotype: F(2,
136) = 10.81 P < 0.0001] **P < 0.01, ***P < 0.001 vs. saline-treated mice. (B) Quantifications of Western blot analyses of TH phosphorylation on Ser40 in protein extracts from the DS of WT, D2S−/−, and D2L−/− mice injected with saline or 0.02 and 0.2 mg/kg quinpirole. Two-way ANOVA, genotype × treatment: F(4,
28) = 2.589; P = 0.0584, n = 3–5 samples/treatment per genotype. *P < 0.05, **P < 0.01, vs. saline treated mice. (C) Motor activity recorded for 1 h in NHC of WT, D2S−/−, and D2L−/− mice injected with either saline or haloperidol (0.1, 0.25 mg/kg). Two-way ANOVA, treatment: F(2,
91) = 92.71, P < 0.0001; genotype: F(2,
91) = 1.057, P = 0.3517, n = 7–16. *P < 0.05, ****P < 0.0001 vs. saline-treated mice. (D) Quantification of the cataleptic behavior upon saline or haloperidol (1 and 4 mg/kg) treatment in WT, D2S−/−, and D2L−/− mice. Two-way ANOVA, genotype × treatment: F(4,
84) = 14.45, P < 0.0001, n = 7–15. ***P < 0.001 vs. saline-treated mice.