Mitochondrial respiratory chain activity in the human brain as a function of age

Age-associated changes in mitochondrial respiratory chain activity were inv estigated in human brain tissue collected at autopsy. Four brain regions, t he frontal cortex, superior temporal cortex, cerebellum and putamen, were s tudied to map any regional variation. A significant decrease in cytochrome c oxidase activity was seen in all regions studied with increasing age (P < 0.05). Although a small decrease in succinate dehydrogenase-cytochrome c o xidoreductase and NADH: ubiquinone oxidoreductase activities was observed, this was not statistically significant. This study has shown that the age-r elated fall in cytochrome c oxidase activity affects the frontal cortex, su perior temporal cortex, cerebellum and putamen. The variation in the extent of age-related oxidative phosphorylation decline was striking. We hypothes ize that individuals with more severe age-related decline may be predispose d to neuronal dysfunction, whereas individuals with well preserved oxidativ e phosphorylation may enjoy some degree of neuronal protection. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.