CORTICAL CYTOCHROME-OXIDASE ACTIVITY IS REDUCED IN ALZHEIMERS-DISEASE

A defect in energy metabolism may play a role in the pathogenesis of n eurodegenerative diseases, such as Alzheimer's disease. In the present study, we examined the activities of the enzymes that catalyze oxidat ive phosphorylation in frontal, temporal, parietal, and occipital cort ex from Alzheimer's disease patients and age-matched controls. Complex I and complex II-III activities showed a small decrease in occipital cortex, but were unaffected in the other cortical areas. The most cons istent change was a significant decrease of cytochrome oxidase (comple x IV) activity of 25-30% in the four cortical regions examined. These results provide further evidence of a cytochrome oxidase defect in Alz heimer's disease postmortem brain tissue. A deficiency in this key ene rgy-metabolizing enzyme could lead to a reduction in energy stores and thereby contribute to the neurodegenerative process.