Peripheral effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its main metabolite 1-methyl-4-phenylpyridinium ion (MPP+) in the rat.

The effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its main metabolite 1-methyl-4-phenyl-pyridinium ion (MPP+) on catecholamine concentrations was tested in some peripheral organs of the rat. Acute injection of either compound caused a marked depletion of heart noradrenaline (NA). MPP+ had more effect than the parent compound. MPTP had no effect on adrenal catecholamines while its metabolite was effective, but only after several hours. Repeated MPTP and MPP+ injections (20 mg/kg X 5) resulted in marked depletion of heart NA and adrenal gland adrenaline. Clear recovery was observed in both organs 10 days after treatment.