The mitochondrial redox-ratio of SNc DaNs is reduced by application of isradipine or Ru360 in MitoPark mice. A, Only application of 5 mm KCN induced an increase of the mitochondrial redox ratio. B, Incubation of midbrain mito-roGFP sections with 300 nm isradipine (similar to Dragicevic et al., 2014; Ortner et al., 2017) for at least 30 min induced a reduction of the redox-ratio in SNc DaNs of control mice, but not in VTA DaNs. Treatment with 20 μm Ru360 only induced a small decrease of the redox ratio in control SNc neurons. On the contrary, the redox ratio was elevated in SNc, but not in VTA neurons of 10–12-week-old MitoPark mice. This SNc-specific high redox ratio in MitoPark mice was diminished by isradipine and Ru360. Data are represented as mean ± SEM (A: Rotenone control: n = 12, rotenone: n = 23, antimycin A control: n = 22, antimycin A: n = 16, KCN control: n = 23, KCN: n = 22, 3–5 mice per condition; B: control VTA n = 21, control SNc n = 22, control VTA + isradipine n = 36, control SNc + isradipine n = 25, control VTA + Ru360 n = 23, control SNc + Ru360 n = 37, MitoPark VTA n = 19, MitoPark SNc n = 35, MitoPark VTA + isradipine n = 34, MitoPark SNc + isradipine n = 26, MitoPark VTA + Ru360 n = 25, MitoPark SNc + Ru360 n = 23, 3–5 mice per condition; #indicates significance between SNc DaNs of MitoPark and control mice). **p < 0.01, ***p < 0.001, ****p < 0.0001.