Biochemical and functional evidence for a marked dopamine releasing action of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (NMPTP) in mouse brain.

The acute effects of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (NMPTP) on mouse central monoaminergic neurons were investigated. In striatum, two hours after the injection of NMPTP (50 mg/kg s.c.) there was a seven-fold increase in 3-methoxytyramine that coincided with a 55% decrease in dopamine. In addition, the same dose of NMPTP caused an acute increase in mouse motor activity; this effect was antagonized by haloperidol or by pretreatment with reserpine. These data indicate that NMPTP initially causes a pronounced release of dopamine into the extraneuronal space.