IMPAIRED SPATIAL MEMORY IN AGED RATS IS ASSOCIATED WITH ALTERATIONS IN INOSITOL PHOSPHOLIPID-METABOLISM

WE have investigated changes in inositol phospholipid turnover and mem brane arachidonic acid concentration in the dentate gyrus and frontal cortex of animals aged 3-6 months, 14 months or 22 months which were t rained in the Morris water maze. Ageing was associated with poorer per formances in the behavioural test, characterized by increased variabil ity in retention and acquisition amongst individuals, a decrease in me mbrane arachidonic acid concentration and increased unstimulated inosi tol phospholipid metabolism in synaptosomes prepared from frontal cort ex and dentate gyrus. Arachidonic acid stimulated inositol phospholipi d metabolism in synaptosomes, but in the older groups, stimulation was associated with good performance in the Morris water maze. In slices prepared from frontal cortex, responsiveness of inositol phospholipid metabolism to glutamate was also age- and performance-dependent. The f indings highlight a correlation between age, inositol phospholipid met abolism and performance in the Morris water maze.