Fig 4. Monoamine levels measurement in overlesioned parkinsonian monkeys.

MPTP administration resulted in an asymmetric parkinsonism in NHP presenting a more severe dopaminergic degeneration on the right striatum than that on the left. Accordingly, analysis of monoamine levels by HPLC revealed that there was a dramatic reduction of DA and its metabolites in the more severely lesioned putamen (right) compared to the mildly lesioned one (left) (a). In contrast, serotonin and its metabolite levels, measured in the same samples, were similarly depleted in both hemispheres (b).