抄録
Docosahexaenoic acid （DHA） is one of the major long chain polyunsaturated fatty acids normally occurring in mammals and fishes. It is found in the highest concentration in the brain and a structural component of neuronal membranes. DHA is localized in the 2-position of membrane phospholipids, especially in phosphatidylethanolamine and may exert considerable influence on the membrane fluidity and functional properties of integral proteins. It has become apparent that a deficiency in DHA is associated with a loss of discriminant learning ability and visual acuity. Moreover, the patients with Alzheimer's disease show extremely low levels of DHA in their brain. However, less data are available on the action of DHA in membrane phospholipids, and little is known about the mechanism by which DHA affects several functions after release by phospholipase A2. Much attention has been focused on the N ‐ methyl ‐ D ‐aspartate （NMDA） receptor because of its role in long-term potentiation （LTP）. The action of DHA on the functional responses to NMDA was examined in neurons acutely isolated from rat in whole-cell and single-channel modes under voltage-clamp condition. DHA potentiated the NMDA response in a concentration-dependent manner. Moreover we investigated the effect of DHA on BEL （bromoenol lactone, an iPLA2 ‐ inhibitor） ‐ impaired LTP, and found that DHA abolished the effect of BEL. Linoleic acid had no effects, either. These results suggest that DHA is crucial for the induction of LTP and that endogenously released DHA during tetanus is sufficient to trigger the formation of LTP.
