In A2AR gene KO groups, treatment with l-DOPA (LID group) can significantly increase the IOD of both GAD65 (sham: 0.056 ± 0.004; PD: 0.092 ± 0.015; LID: 0.149 ± 0.013) and GAD67 (sham: 0.014 ± 0.005; PD: 0.036 ± 0.007; LID: 0.072 ± 0.013) (n = 4, Ftreatment = 5.324, P < 0.05 vs. PD group or sham group, ANOVA and followed by LSD post hoc analysis, Figure 2). Here, GAD1 is linked to Parkinson disease.