Similarity and dissimilarity of MPTP models to Parkinson's disease: importance of juvenile parkinsonism.

Clinical, pharmacological and neuropathological features of MPTP-induced parkinsonism in humans and animals were compared with those of the Parkinson's disease (PD) and juvenile parkinsonism (JP). Some dissimilarities between both the conditions noticed in earlier investigations have been dissolved by starting a well-prescribed chronic administration of subliminal dose of MPTP in old matured monkeys. The MPTP model is now more resembling parkinsonism. However, it is to be emphasized that the MPTP model is more similar to JP than to PD in clinical and pharmacological terms. JP has been considered idiopathic in nature and seems to be important in understanding of etiopathogenesis of PD. Findings in one sectioned brain of JP were described with stronger pharmacological changes in the striatum than in the nigra and preservation of nigral neurons. It is thus questioned whether PD is the disease starting by striatal chemical changes or by nigral pathology.