N-Acetylcysteine elicited increase in complex I activity in synaptic mitochondria from aged mice: implications for treatment of Parkinson's disease

It has been suggested that thiolic groups are essential for complex I activ ity and other respiratory mitochondrial enzymes. Recent experiments showed that the thiolic antioxidant N-acetylcysteine (NAC) can protect against age -related decrease in complex I activity in mice hepatic mitochondria. The p resent paper shows that NAC enhances complex I activity in vitro in synapti c mitochondria isolated from old mice. The optimum NAC concentration for ma ximum complex I activity was 10 mM in old synaptic preparations. Our data s uggest that mitochondrial thiolic groups, which are essentials to oxidative phosphorylation, are impaired by aging. Based on the finding of decreased mitochondrial complex I activity in the substantia nigra of patients with P arkinson's disease, we propose that the thiol-containing antioxidant NAC co uld be beneficial for treatment of the disease. (C) 2000 Published by Elsev ier Science B.V. All rights reserved.