Intracerebroventricular administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its metabolite 1-methyl-4-phenylpyridinium ion (MPP+) decrease dopamine and increase acetylcholine in the mouse neostriatum.

We found that both MPTP and its metabolite MPP+ decrease dopamine and increase acetylcholine content of mouse neostriatum when administered intracerebroventricularly (ICV). These observations support the notion that MPP+ may be the active neurotoxin formed in brain after MPTP administration. They also suggest that cholinergic mechanisms may be a target of the neurotoxin.