DRD1 and Parkinson disease: There was a decrease of 42% (P < 0.001, one-way ANOVA) in the D1R-Gαolf PLA signal in PD-D mice when compared to PD mice (Figure 5F; PD mice, 192 ± 25%; PD-D mice, 150 ± 21%; % of naïve control mice ± SEM; n = 10).