Effect of n-3 fatty acid deficiency on fatty acid composition and metabolism of aminophospholipids in rat brain synaptosomes.

Docosahexaenoic acid (DHA, 22:6n-3) is one of the major polyunsaturated fatty acids esterified predominantly in aminophospholipids such as ethanolamine glycerophospholipid (EtnGpl) and serine glycerophospholipid (SerGpl) in the brain. Synaptosomes prepared from rats fed an n-3 fatty acid-deficient safflower oil (Saf) diet had significantly decreased 22:6n-3 content with a compensatory increased 22:5n-6 content when compared with rats fed an n-3 fatty acid-sufficient perilla oil (Per) diet. When the Saf group was shifted to a diet supplemented with safflower oil plus 22:6n-3 (Saf + DHA) after weaning, 22:6n-3 content was found to be restored to the level of the Per group. The uptake of [3H]ethanolamine and its conversion to [3H]EtnGpl did not differ significantly among the three dietary groups, whereas the formation of [3H]lysoEtnGpl from [3H]ethanolamine was significantly lower in the Saf group than in the other groups. The uptake of [3H]serine, its incorporation into [3H]SerGpl, and the conversion into [3H]EtnGpl by decarboxylation of [3H]SerGpl did not differ among the three dietary groups. The observed decrease in lysoEtnGpl formation associated with a reduction of 22:6n-3 content in rat brain synaptosomes by n-3 fatty acid deprivation may provide a clue to reveal biochemical bases for the dietary fatty acids-behavior link.