The Effect of a Low n-6 Polyunsaturated Fatty Acid Diet on the Rate of Loss of Arachidonic Acid and Docosahexaenoic Acid from Rat Brain Phospholipids

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are the predominant n-6 and n-3 polyunsaturated fatty acids (PUFA) in the brain, and alterations in their metabolism are thought to play a role in several neurological disorders. This thesis investigates how lowering dietary n-6 PUFA affects the rate of loss of ARA and DHA from rat brain phospholipids. Rats were fed a low (2% linoleic acid) or high (24% linoleic acid) n-6 PUFA diet for 15 weeks post-weaning. Baseline brain phospholipid fatty acid, eicosanoid and docosanoid concentrations were then measured. The remaining rats underwent intracerebroventricular infusion of 3H-ARA /3H-DHA and the loss of radioactivity was measured over time to determine the rate of ARA/DHA loss. Low (vs. high) n-6 PUFA rats exhibited slower loss of ARA and more rapid loss of DHA. These changes in PUFA metabolism may provide insight into mechanisms of dietary-lipid-driven treatments, particularly low n-6 PUFA, for neurological disorders.M.Sc