Mitochondria, free radicals, and neurodegeneration.

A central role for defective mitochondrial energy production, and the resulting increased levels of free radicals, in the pathogenesis of various neurodegenerative diseases is gaining increasing acceptance. Defects in energy metabolism may contribute to both excitotoxicity and oxidative damage. Evidence implicating energy defects in neurodegenerative diseases comes from similarities to known mitochondrial disorders, including delayed and variable age of onset, slow progression, and symmetric degeneration of circumscribed groups of neurons.