Effect of dietary n-3 fatty acid deficiency on blood-to-brain transfer of sucrose, α-aminoisobutyric acid and phenylalanine in the rat

Abstract

Possible alterations in blood-to-brain unidirectional transport of sucrose (mol. wt., 342), α-aminoisobutyric acid (mol. wt., 104), and l-phenylalanine (mol. wt., 165) induced by a diet deficient in n-3 polyunsaturated fatty acids were studied with respect to blood-brain barrier function. Two groups of rats were for to two generations with a semisynthetic diet. One group of rats was fed a peanut oil + rapeseed oil diet which contained both essential fatty acids: linoleic acid (18:2 n-6) and α-linolenic acid. (18:3 n-3). Another group was fed a diet of peanut oil, this diet (containing 18:2 n-6) was deficient in α-linolenic acid. The experiments were performed at 6 months of age. Unidirectional transfer rate constants ( K i) of sucrose, α-aminoisobutyric acid and l-phenylalanine were measured. The diet based on peanut oil (deficient in n-3) caused a greater blood-to-brain transport of sucrose but not of α-aminoisobutyric acid or l-phenylalanine. These observations indicate that regardless of the mechanisms involved, alterations in essential fatty acids induced by diet can modulate to some extent the blood-brain transport of hydrophilic molecules without a carrier.