Arachidonic acid barrier

Physiological Function of n-6 DPA Reported to Date. Not only is the occurrence of n-6 DPA rare in the biosphere it is also a minor fatty acid in mammals. Of the n-6 essential fatty acids (EFA) for primates or humans, linoleic acid (LA, 18 2n-6) and arachidonic acid (AA, 20 4n-6) are the most prominent and important. Among the docosapolyenoic acids (22-carbon chain), which can cross the blood-brain barrier more than the eicosapolyenoic acids (20-carbon), DHA (an n-3 EFA) is the most important. In mammals, the levels of n-6 DPA in brain and retina increase in accordance with n-3 essential fatty acid deficiency (EFAD). Is the increase only compensatory for DHA or does n-6 DPA have any positive physiologic functions ... 

Hansen, H.S. and Jensen, B., Essential function of linoleic acid esterified in acylglucosyl ceramide and acylceramide in maintaining the epidermal water permeability barrier evidence from feeding studies with oleate, linoleate, arachidonate, columbinate and alpha-linoleate, Biochim. Biophys. Acta, 834, 357, 1985. 

Hansen, H.S., and Jensen, B. (1985) Essential Function of Linoleic Acid Esterified in Acylglucosylceramide and Acylce-ramide in Maintaining the Epidermal Water Permeability Barrier. Evidence from Feeding Studies with Oleate, Linoleate, Arachidonate, Columbinate, and a-Linolenate, Biochim. Biophys. Acta 834,357-363. 

The rate of accumulation of PUFA in the developing brain (Sinclair Crawford, 1972), the formation from the precursors in the CNS (Mead, 1976), the passage from the blood through the blood-brain barrier (Dhopeshwarkar Mead, 1969 1970) and the incorporation into brain lipids of both the short-chain unsaturated precursors (linoleic and linolenic acids) and the long-chain polyunsaturated derivatives (arachidonic and docosahexaenoic acids) following oral administration (Sinclair, 1975), have been studied in detail. 

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