Table 1.

Effects of channel blockers, metabolic substrates, and NOS inhibitors on MPP⁺ toxicity

Drug class	Survival (% of control)
1 μm MPP⁺	25.40 ± 4.49
Glutamate/calcium channel inhibitors
1 μm MK-801	25.40 ± 8.98
30 μm NBQX	25.40 ± 5.99
300 μm AIDA	29.63 ± 5.18
10 μmnifedipine	38.10 ± 10.37
Metabolic substrates
10 mm glucose	33.31 ± 7.87
0.5 mm succinate	36.80 ± 1.47**
NOS inhibitors
1 μm MPP⁺	28.00 ± 2.92
2.5 mm nitro-l-arginine	40.00 ± 3.34*
5 μm 7-nitroindazole	40.00 ± 2.3

Primary mesencephalic cultures were treated with 1 μm MPP⁺ in the presence of the indicated drugs and stained for TH 48 hr later. The number of surviving TH neurons was normalized to vehicle-treated controls. Data are mean ± SEM. * p < 0.01, ** p < 0.001 compared with MPP⁺-treated cultures (ANOVA with post hoc Student’s t test).