At the protein level, compared with the control group, the striatal mGluR2/3 protein expression of the PD group was decreased, with statistically significant differences (P < 0.01); compared with the PD group, the striatal mGluR2/3 protein expression of the PD + exercise group was increased, with statistically significant differences (P < 0.05, Figure 9). This evidence concerns the gene GRM2 and Parkinson disease.