Age-related changes in LTP and antioxidant defenses are reversed by an alpha-lipoic acid-enriched diet

Among the age-related changes identified in rat hippocampus are impairments in LTP and glutamate release. These deficits have been coupled with decrea sed arachidonic acid concentration. In this study we compared LTP and gluta mate release in groups of aged and young rats fed for 8 weeks on a control diet or on a diet enriched in alpha-lipoic acid. Dietary supplementation in aged rats restored hippocampal arachidonic acid concentration to levels ob served in tissue prepared from young rats. We observed that aged rats that received the distinguishable from young rats whereas the experimental diet sustained LTP in perforant path-granule cell synapses in a manner indisting uishable age-related impairment in glutamate release was reversed in synapt osomes prepared from dentate gyrus obtained from these rats. The evidence p resented supports the hypothesis that the alpha-lipoic acid-enriched diet h as antioxidant properties, because the age-related increase in superoxide d ismutase activity and decrease in alpha-tocopherol concentration were rever sed. The finding that the age-related increase in interleukin-1 (IL-1)beta concentration was also reversed suggests a possible role for this cytokine in ageing. (C) 2000 Elsevier Science Inc. All rights reserved.