MUSCLE RESPIRATORY-CHAIN ENZYME-ACTIVITIES IN PARKINSONS-DISEASE AND IN MULTISYSTEM EXTRAPYRAMIDAL DISORDERS WITH PARKINSONISM AS THE MAIN CLINICAL-FEATURE

A primary mitochondrial dysfunction has been recently hypothesized in the pathogenesis of Parkinson's disease (PD). As a matter of fact, MPT P (a drug able to induce neuronal toss in substantia nigra) is a speci fic inhibitor of Complex I, while controversial data on Complex I defi ciency have been reported in platelets, muscle and brain of patients a ffected by Parkinson's disease. Here we report data on respiratory cha in enzyme activities in isolated muscle mitochondria from 6 patients w ith classical PD (two with the hereditary form, HPD), and in 6 patient s with a multisystem extrapyramidal disorder (MSED) with parkinsonism as the main clinical feature. While histological and biochemical evide nce of mitochondrial dysfunction has been detected in 1 case with PD a nd in 3 cases with MSED, normal results have been obtained in the othe r cases confirming the extreme clinical and biochemical heterogeneity of these disorders.