Figure 4.

Sunitinib prevents MPP ⁺‐induced enhancement of endogenous NOS activity in SH‐SY5Y cells. SH‐SY5Y cells were pre‐incubated with sunitinib, 7‐NI, or DMSO (0.05%; vehicle control; black bar) at the indicated concentrations for 2 h and exposed to 1 mM MPP ⁺. SH‐SY5Y cells placed at normal medium (white bar) were regarded as a control. Endogenous NOS activity was measured at 24 h after MPP ⁺ challenge using colorimetric NOS activity assay. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; **P < 0.01 versus MPP ⁺ group (anova and Dunnett's test). NOS, nitric oxide synthase.