Table 1

Time course of MPP⁺-induced dopaminergic cell death

Treatment
First 24 h	Second 24 h	Survival of Dopaminergic Neurons
		% control
MPP⁺	MPP⁺	17.3 ± 2.12^1-150 ^1-160
MPP⁺	Control	57.6 ± 5.64^1-160
Control	MPP⁺	46.5 ± 5.51^1-160

Mesencephalic neurons were incubated in the presence or absence of MPP⁺ (5 μM) for two consecutive 24-h periods before fixation. The number of surviving dopaminergic neurons was counted from TH-immunostained cultures and expressed as a percentage of controls. Data show mean ± S.E.

↵1-150 P < .01 versus MPP⁺/control and control/MPP⁺.
↵1-160 P < .01 versus untreated control group. Four separate cultures per group, with 12 fields counted in each culture.