Figure 1: Differences in the toxic effects of mild and acute MPP+ exposure.

(a,b) SH-SY5Y cells were exposed to MPP+ for up to 48 h or to 2.5 and 5 mM MPP+ for up to 24 h; cell viability at various time points was determined using the WST-1 assay. (c,d) Various densities of SH-SY5Y cells were exposed to 10 and 200 μM MPP+ for 48 h or 2.5 and 5 mM MPP+ for 24 h, and cell viability was determined using the WST-1 assay. Data are expressed as means ± standard deviations (S.D.) from at least three independent experiments. *p < 0.05, **p < 0.01.