ABSTRACT
Reactive oxygen species (ROS) are a natural byproduct of aerobic living condi tions. Although the organism and the cells have developed powerful strategies to defend themselves against the high reactivity of ROS, under certain conditions ROS can lead to massive alterations in cell functions and ultimately to cell death. ROS have been suggested to be implicated in the pathogenesis of a variety of nonneuronal and neuronal disorders including artherosclerosis, stroke, cerebral ischemia, amyotrophic lateral sclerosis, and Parkinson’s disease (1-4). Compared to other tissues that can be damaged by ROS, the brain is particularly vulnerable to oxidation. Most importantly, neuronal membranes of the brain consist of high concentrations of polyunsaturated fatty acids which are potential substrates for peroxidation reactions. Moreover, the brain has only low levels of antioxidant defense enzymes compared to other tissues (1).
