Rotenone upregulates VGLUT2 protein expression in surviving DA neurons. A, Representative 20× and (B) 100× images showing an upregulation of VGLUT2 in the VTA and SNc of rotenone-treated rats. Scale bar, 30 µm. C, While there was no significant change in relative intensity of VGLUT2⁺ puncta in either the VTA or SNc, there was a significant increase in (D) VGLUT2⁺ puncta density and (E) the number of VGLUT2-immunoreactive puncta within TH⁺ cells. Data are mean ± SEM. N = 3-8 per group. *p < 0.05. **p < 0.01.