Age-related changes in oxidative mechanisms and LTP are reversed by dietary manipulation

Aged rat. exhibit nn impaired ability to sustain long-term poptentiation in dentate gyrus which correlates with a decrease in arachidonic concentratio n. Here we confirm the previous finding that dietary supplementation with a rachidonic acid and its precursor. gamma-linolenic acid, reversed the impai rment in LTP in aged rats and report that there is a significant correlatio n between membrane arachidonic acid concentration and response to tetanic s timulation. We observed that age was associated with decreases in the conce ntration of vitamins C and E and increased activity of superoxide dismutase , indicative of a compromise in antioxidative defenses; these changes were paralleled by increases in interleukin-1 beta (IL-I beta) concentration and lipid peroxidation. Dietary manipulation restored polyunsaturated fatty ac id concentrations to values observed in tissue prepared from young rats and reversed the age-related changes in vitamins E and C, IL-1 beta concentrat ion and superoxide dismutase activity. We propose that these changes revers e the increase in lipid peroxidation and thereby the age-related change in polyunsaturated fatty acids. (C) 2000 Elsevier Science Inc. All rights rese rved.