Fig. 1. Buffering of cytosolic calcium attenuates MPP⁺-mediated toxicity in MN9D cells.

a–d MN9D cells were treated with vehicle (control, CTRL) or 50 μM MPP⁺ in the presence or absence of 30 μM BAPTA-AM for 30 h. a MN9D cells were stained with 3 µM Fluo-3. A representative image of cells was taken using confocal microscopy after fixation. The scale bar represents 20 μm. b Cytosolic Ca²⁺ levels were assessed using flow cytometry. c MTT reduction assays were performed to assess cell viability that is expressed as a percentage of untreated control cells (100%). Bars represent the mean ± SEM of three independent experiments in triplicate. ^*p < 0.05; ^**p < 0.01; ^****p < 0.0001. d Electron micrographs of MN9D cells were taken after drug treatment. Lower panels are magnified images from the boxed areas. Mitochondria (white arrowheads), lysosomes (yellow arrowheads) and autophagosomes (red arrowheads) are indicated