FIGURE 3.

Mutation of D2S PKC phosphorylation sites prevents NT-mediated reduction in D2R function in cultured DA neurons. Patch clamp whole-cell recordings of DA neurons in culture transfected with either a normal D2S receptor (D2S-WT) or a version in which three PKC phosphorylation sites (T225A, S228G, and S229G) have been mutated (D2S-Mut). A, example of a transfected cultured DA neuron identified by immunostaining against the DA transporter (green) and the FLAG epitope of D2S-WT (red). Scale bar, 25 μm. B, example of a patch clamp recording in a DA neuron transfected with D2S-WT following a typical NT treatment protocol. C, same as in B but in a neuron transfected with D2S-mut. D, average effect of the D2 agonist Quin on firing rate in the absence (Quin) or presence of NT preapplication (Quin+NT) in the two transfection conditions of B and C. **, p < 0.01; two-way ANOVA with Bonferroni multiple comparison tests (n = 7 for D2S-WT and 5 for D2S-Mut).