Reversibility of n-3 fatty acid deficiency-induced alterations of learning behavior in the rat: level of n-6 fatty acids as another critical factor.
Rats fed a semipurified diet supplemented with 3% (w/w) safflower oil [Saf, n-3 fatty acid deficient, high linoleic acid (18:2n-6)] through two generations exhibit decreased correct response ratios in a brightness-discrimination learning test compared with rats fed 3% perilla oil [Per, high alpha-linolenic acid (18:3n-3)]. This is associated with a decreased DHA (22:6n-3)-to-arachidonic acid (20:4n-6) ratio in brain lipids. In the first set of experiments, dietary oil was shifted from Saf to a mixture of 2.4% safflower oil plus 0.6% DHA after weaning (Saf-DHA), but all parameters measured in the learning test were essentially unchanged. Brain 22:6n-3 content of the Saf-DHA group reached that of the Per group but the levels of 20:4n-6 and docosatetraenoic acid (22:4n-6) did not decrease to those of the Per group at the start of the test. In the second set of experiments, dietary oil was shifted to a mixture of 0.6% safflower oil plus 1.2% oleic acid (OA) plus 1.2% DHA (Saf-OA-DHA group) with 18:2n-6 content comparable to that of the Per group. The Saf-OA-DHA group exhibited a learning performance similar to that of the Per group; brain 22:6n-3, 20:4n-6, and 22:4n-6 contents were also comparable to those of the Per group. These results indicate that the altered learning behavior associated with a long-term n-3 fatty acid deficiency is reversed by supplementing 22:6n-3 after weaning, when the levels of competing n-6 fatty acids in the diet and brain lipids are limited.
Ikemoto
A
A
Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori, Mizuhoku, Nagoya 467-8603, Japan.
Ohishi
M
M
Sato
Y
Y
Hata
N
N
Misawa
Y
Y
Fujii
Y
Y
Okuyama
H
H
D000375:Aging / Q000502:physiology; D000818:Animals; D002490:Central Nervous System / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000032:analysis / Q000172:deficiency* / Q000494:pharmacology*; D005260:Female; D007858:Learning / Q000187:drug effects*; D008027:Light; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D010938:Plant Oils; D051381:Rats; D012054:Reinforcement, Psychology; D012450:Safflower Oil / Q000008:administration & dosage / Q000494:pharmacology*; D014796:Visual Perception / Q000187:drug effects; D014886:Weaning; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000494:pharmacology
D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010938:Plant Oils; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; C058216:perilla seed oil; D012450:Safflower Oil