Effect of Wnt5a on number of TH neurons and morphological changes in mesencephalic neuronal cultures from WT and D2R−/− mice. A, effect of treatment with quinpirole (1 μm), Wnt5a (100 ng/ml), Wnt5a plus quinpirole (1 μm), Wnt5a plus haloperidol (1 μm), Wnt5a plus quinpirole plus haloperidol, Wnt5a plus PD98059 (50 μm), Wnt5a plus quinpirole plus PD98059 with a control group on the mesencephalic neuronal cultures from WT and D2R−/− mice. TH neurons were visualized using immunocytochemistry. Scale bar, 100 μm. B–D, effect of treatments on the numbers of TH neurons (B), neurite length (C), and neurite number (D) on mesencephalic neuronal cultures from WT and D2R−/− mice. Mean values ± S.E. are shown for WT (n ≥ 5) and D2−/− (n ≥ 5). *, p < 0.05; **, p < 0.01; ***, p < 0.001, ANOVA followed by a Newman-Keuls test for control versus drug-treated cells. †, p < 0.05; ††, p < 0.01; †††, p < 0.001, unpaired t test for WT and D2R−/− mice. Quin, quinpirole; Halo, haloperidol.