THE NEUROTOXIC ACTIONS OF 1-METHYL-4-PHENYLPYRIDINE (MPP+) ARE NOT PREVENTED BY DEPRENYL TREATMENT

1-Methyl-4-phenylpyridine (MPP+) injected into the cerebral ventricles (ICV) of mouse caused depletions of striatal dopamine (DA) (-42%),3,4-dihydroxyphenylacetic acid (DOPAC) (-34%) and homovanillic acid (HVA) (-16%) content without significant reductions in levels of noreadrenaline (NA), serotonin (5-HT) or 5-hydroxyindoleacetic acid (5-HIAA). When deprenyl was administered before MPP+, striatal DA and its metabolites were further depleted, and striatal NA and 5-HT levels also were reduced. Further, whilst ICV MPP+ alone failed to influence the biochemistry of the limbic areas (nucleus accumbens plus tuberculum olfactorium), in the presence of deprenyl MPP+ caused 20-40% reductions in levels of limbic NA, DA, DOPAC, HVA, 5-HT and 5-HIAA. Therefore, deprenyl treatment does not prevent the neurotoxic actions of MPP+, indeed, a more extensive neurotoxicity for MPP+ is revealed in the presence of this monoamine oxidase inhibitor.