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 fat ty acids esterified predominantly in aminophospholipids such as ethanolamin e glycerophospholipid (EtnGpl) and serine glycerophospholipid (SerGpl) in t he brain. Synaptosomes prepared from rats fed an n-3 fatty acid-deficient s afflower 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 f atty 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 w eaning, 22:6n-3 content was found to be restored to the level of the Per gr oup. The uptake of [H-3]ethanolamine and its conversion to [H-3]EtnGpl did not differ significantly among the three dietary groups, whereas the format ion of [H-3]lysoEtnGpl from [H-3]ethanolamine was significantly lower in th e Saf group than in the other groups. The uptake of [H-3]serine, its incorp oration into [H-3]SerGpl, and the conversion into [H-3] EtnGpl by decarboxy lation of [H-3]SerGpl did not differ among the three dietary groups. The ob served decrease in lysoEtnGpl formation associated with a reduction of 22:6 n-3 content in rat brain synaptosomes by n-3 fatty acid deprivation may pro vide a clue to reveal biochemical bases for the dietary fatty acids-behavio r link.