GAD2 and Parkinson disease: Immunohistochemical studies showed significant increase of GAD65 (sham: 0.063 ± 0.007; PD: 0.081 ± 0.007; LID: 0.168 ± 0.013) and GAD67 (sham: 0.012 ± 0.001; PD: 0.055 ± 0.006; LID: 0.109 ± 0.010) in WT-LID compared to WT-sham and WT-PD groups (n = 4, P < 0.05, two-tailed Student’s t-test, Figure 2).