Methamphetamine protects against MPTP neurotoxicity in C57BL mice.

Methamphetamine (5 mg/kg) administered 30 min prior to each injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (3 x 30 mg/kg, at 24 h intervals) prevents the reduction of striatal levels of dopamine and its metabolites in C57BL mice. Methamphetamine and amphetamine inhibit the uptake of 1-methyl-4-phenylpyridinium (MPP+) by striatal synaptosomes of rats. A 30-min post-treatment with methamphetamine or amphetamine also prevents the MPTP-induced dopamine depletion, suggesting that their protective effect is related to the blockade of MPP+ uptake into dopaminergic neurons. Since amphetamine and methamphetamine are themselves neurotoxins at higher doses, this work demonstrated the protection against the actions of one neurotoxin by the administration of another.