Dietary Docosahexaenoic Acid [22: 6(n-3)] as a Phospholipid or a Triglyceride Enhances the Potassium Chloride–Evoked Release of Acetylcholine in Rat Hippocampus
The Journal of Nutrition. 2005-05-01; 135(5): 1008-1013
DOI: 10.1093/jn/135.5.1008
Lire sur PubMed
Aïd S(1), Vancassel S, Linard A, Lavialle M, Guesnet P.
Author information:
(1)INRA, Laboratoire de Nutrition et Sécurité Alimentaire, Jouy-en-Josas,
France.
We demonstrated previously that a dietary-induced depletion of docosahexaenoic
acid (DHA) in cerebral phospholipids increases the spontaneous release of
acetylcholine (Ach) in the rat hippocampus and reduces its potassium chloride
evoked-release. In the present study, we investigated the effects in rats of
DHA-enriched diets supplied by egg phospholipids (E-PL) or tuna oil (TO) on the
PUFA in hippocampus membranes and on the synaptic release of Ach. Control rats
were fed 3 g/kg of the DHA precursor, alpha-linolenic acid (LNA). Chronically
(n-3) PUFA-deficient females were fed, starting 2 wk before mating, the
deficient diet, a control diet, or a purified diet supplying 1, 2, or 3 g DHA/kg
diet as E-PL or TO. Experiments were performed on the adult male progeny fed the
same diet as their dams throughout life. The form of dietary DHA (TO or E-PL)
did not influence its incorporation into the hippocampus. The 1 g DHA/kg diets
allowed maximal incorporation into phosphatidylethanolamine (PE), but 2 g DHA/kg
diet was needed for phosphatidylcholine (PC). A minimum of 2 g DHA/kg was needed
to decrease the basal Ach release and to enhance the stimulated release to that
of the control; the Ach release of the 1 g/kg DHA-groups did not differ from
that of the deficient group. This suggests that >1 g DHA/kg diet is needed to
ensure PUFA incorporation into PE and PC, and basal and stimulated Ach release
in the rat hippocampus equivalent to the control group fed only LNA. PUFA
incorporation into the hippocampus depends mainly on the PUFA concentration of
the diet, not on the form of dietary DHA.