Figure 1.

D2S receptors are specifically involved in the regulation of the state of phosphorylation of TH. Striatal slices from wild-type mice (A), D2 KO mice (B), and 2DL KO mice (C) were incubated for 10 min in the presence of quinpirole (10 nM to 1 μM). The levels of phospho[Ser-40]-TH were determined as described in Materials and Methods. (Upper) Representative autoradiograms. (Lower) Summary of data expressed as means ± SEM (n = 6). The amount of phosphorylated TH is expressed as a percentage of that determined in the absence of quinpirole (control). *, P < 0.01 and **, P < 0.001 vs. respective control group; one-way ANOVA followed by Dunnett's test.