[The influence of reactive oxygen species on the central nervous system].

Oxidative stress can be defined as a rise of oxidative potential or decrease of antioxidant status. Oxidative stress is caused by reactive oxygen species (ROS) which are produced by one-electron reduction of oxygen in the electron transport chain, as well as many other reactions. Effects of ROS can result in cellular membrane damage, structural and functional changes in enzymatic and non-enzymatic proteins, and damage to the DNA structure. Excessive generation of free radicals, decrease of enzymatic antioxidant activity, and/or reducing agents are considered as the main causes of oxidative stress. Since the brain contains a large amount of polyunsaturated fatty acids, consumes up to 20% of oxygen used by the whole body, and shows low antioxidant activity, it seems to be especially vulnerable to oxidative stress. Numerous data show the significant role of oxidative stress in pathogenesis of many neurodegenerative diseases.