[Protection against radical peroxidations in cerebral aging in cerebral capillaries and microvessels].

Systemic injection of substances that generate free radicals into the rat induces deleterious alteration of various tissues (as demonstrated by the production of conjugated dienes and malondialdehyde) but only has a slight effect on the brain. This shows that the blood-brain barrier has important protective properties. In fact the cerebral capillaries and microvessels have superoxide dismutase, glutathione peroxidase, and catalase activities higher than those found in the rest of the cerebral tissue during aging. These activities vary little, except for catalase which decreases. But, curiously, the concentrations of Mn, Cu, and Zn are not related to enzymatic activity, although the micro-elements are necessary for the activity of superoxide dismutase. On the other hand, during aging, the capillaries and cerebral microvessels undergo extensive modifications at the level of the polyunsaturated fatty acids: for example, the concentration of arachidonic acid decreases by half.