ABSTRACT
Docosahexaenoic acid (DHA) is a fatty acid found in high concentrations in brain[1] where it is concentrated in the phospholipids of synaptosomal membranes[2] and synaptic vesicles.[3] Animal studies conducted since the 1970s have investigated the effect of feeding an 18:3n-3-deficient diet during development on brain fatty acid composition and animal behavior. There is now an extensive literature on the biochemical and behavioral effects of 18:3n-3 deficiency. Brain phospholipid DHA decreases while at the same time there is an increase in a metabolite of linoleic acid (18:2n-6), docosapentaenoic acid (DPA, 22:5n-6).[4] Functionally, animals fed 18:3n-3-deficient diets have normal growth, reproduction, and lifespan. However, they have impaired visual development,[5,6] reduced pain threshold,[7] longer duration looking,[8] stereotyped behavior, and greater whole body activity.[9] The latter suggests alterations in brain dopamine function.[9] Indeed, dopamine neurotransmission is altered by several generations of an 18:3n-3-deficient diet[10] and dopamine-related behaviors and neurotransmission are influenced positively by intake of fish oil, which contains DHA.[11] Levant et al.[12] reported recently that even a modest reduction in rat brain 148DHA (~25%) and the concomitant increase in brain DPA prior to weaning resulted in increased basal and amphetamine-stimulated activity, and reduced haloperidol-induced catalepsy, which evinced alterations in dopamine systems.
