Immunoblotting showed unaltered protein levels of both D1R (A) and DAT (B) in dorsal striatum of hemizygous TH-Cre mice when compared to WT. Upper panels: densitometric analysis of immunoblots for TH-Cre and WT (n = 3). D1R and DAT expression levels were normalized to β-actin. A + B, lower panels: representative immunoblots for D1R, DAT and β-actin. C: Saturation curve for DA uptake in striatal synaptosomes from hemizygous TH-Cre mice (blue triangles, n = 3) and WT littermates (black circles, n = 4) of triplicate determinations. There was no significant genotype difference in the maximal dopamine uptake capacity (Vmax) (Vmax WT = 33.4 ± 5.0 fmol/min/ug protein; Vmax TH-Cre = 26.8 ± 1.5 fmol/min/ug protein, P = 0 .33). D1R: D1-receptor, DA: dopamine, DAT: dopamine transporter, WT: wild-type