EGFR inhibitors prevent the changes in the number of TH neurons and morphology in cultured mesencephalic neurons induced by D2R agonist/Wnt5a. A, treatment with Wnt5a (100 ng/ml), Wnt5a plus quinpirole (1 μm), Wnt5a plus AG1478 (10 μm), Wnt5a plus quinpirole plus AG1478 (10 μm), Wnt5a plus PD168393 (1 μm), Wnt5a plus quinpirole plus PD168393 (1 μm), control, in mesencephalic neuronal cultures from WT and D2R−/− mice. TH neurons were visualized using immunocytochemistry. Scale bar, 100 μm. B–D, effect of treatment with combination of drugs on the numbers of TH neurons (B), neurite length (C), and neurite number (D) analyzed in mesencephalic neuronal cultures from WT and D2R−/− mice. Mean values ± S.E. are shown for WT (n = 6) and D2R−/− (n = 6). ***, p < 0.001, ANOVA followed by a Newman-Keuls test for control versus drug-treated cells of WT mice. †, p < 0.05; ††, p < 0.01; †††, p < 0.001, ANOVA followed by a Newman-Keuls test for control versus drug-treated cells of D2R−/− mice. Quin, quinpirole.