MITOCHONDRIAL RESPIRATORY-CHAIN ACTIVITY IN SKELETAL-MUSCLE FROM PATIENTS WITH PARKINSONS-DISEASE

Different abnormalities in mitochondrial electron transport chain acti vity have been demonstrated in muscle and other tissues of patients wi th idiopathic Parkinson's disease (PD). We studied eight Spanish patie nts with PD to evaluate the functional activity of the electron transp ort chain in muscle mitochondria from patients of this country. We fou nd lower complex I activity (nmol.min-1.mg-1) in patients (245.8 +/- 4 2.8) than in controls (331.6 +/- 60.1) (p = 0.004) and lower complex I V activity in patients (46.1 +/- 9) than in controls (144.1 +/- 42.3) (p = 0.00001). Complex V activity was also decreased in two patients a nd complex II and III activities were normal in all of them. Although these results strongly suggest an alteration in mitochondrial DNA in P D, the various electron transport chain defects in different tissues s eem to be nonspecific.