Distinct mechanisms underlie neurotoxin-mediated cell death in cultured dopaminergic neurons - PubMed (original) (raw)

6-OHDA and MPP+differentially affect mitochondrial membrane potential (ΨΔm) and induce ROS formation.A, Time course of ΨΔm in 5,7-DHT-labeled dopaminergic neurons treated with 15 μ

m

6-OHDA (•) or 1 μ

m

MPP+ (○). After drug treatments, cells were loaded with 0.3 μ

m

Rh 123 for 20 min and assayed using a laser scanning confocal microscope. Values correspond to average pixel intensity normalized to baseline fluorescence values from vehicle-treated cells. B, Time-dependent changes in ROS production in dopaminergic neurons treated with 1 μ

m

MPP+. After treatment with 1 μ

m

MPP+ for the indicated time period, cells were incubated with 15 μ

m

DHR for 20 min, rinsed, and imaged by confocal microscopy. Values correspond to fluorescence intensity and are normalized to vehicle-treated labeled dopaminergic neurons.C, Time-dependent induction of ROS formation in dopaminergic neurons treated with 15 μ

m

6-OHDA or 1 μ

m

MPP+. After treatment with either drug for 0, 0.25, 0.5, 1, 3, and 6 hr, cells were loaded with 10 μg/ml DHE for 15 min at 37°C, fixed, stained for TH, and assayed by confocal microscopy. Values represent normalized DHE fluorescence from TH-immunoreactive neurons. Data are mean ± SEM of determinations made in three separate cultures. *p < 0.01; **p< 0.001, compared with values for vehicle-treated cultures (ANOVA with_post hoc_ Student’s t test).