Fatty acid in brain

Recent interest has focused on the C20 5 eicosa-pentaenoic acid (EPA) and the C22 6 docosa-hexaenoic acids (DHA). These 3 (or n-3) polyunsaturated acids are formed from linolenic acid by marine algae and are found in fish oils.h The C22 5 and C22 6 acids can be converted to prostaglandins of the PG4 and PG5 series. DHA together with the 0)6 C22 4 acid constitutes over 30% of the fatty acids in brain phospholipids. In the... 

Kitajka K., Puskas L. G., Zvara A., Hackler L. J., Barcelo-Coblijn G., Yeo Y. K., and Farkas T. (2002). The role of n-3 polyunsaturated fatty acids in brain Modulation of rat brain gene expression by dietary n-3 fatty acids. Proc. Natl. Acad. Sci. USA 99 2619-2624. 

Estimated Acyl-CoA Dilution Coefficients X, and Half-Lives of Fatty Acids in Brain Phospholipids of Awake Rats... 

Spector AA. Plasma free fatty acid and lipoproteins as sources of polyunsaturated fatty acid in brain. J Mol Neurosci, in press. 

The basic pathways for fatty acid biosynthesis and palmitic acid biosynthesis have already been discussed. But the biosynthesis of fatty acid in brain raises special problems, especially with respect to the biosynthesis of long-chain, even- and odd-numbered saturated or unsaturated fatty acids. 

Since the double bond of the 2-hydroxy fatty acids is in the same position as the double bond of the unsaturated fatty acids in brain, it is assumed that these fatty acids are also derived from the unsatured fatty acids. 

An acylase converts sphingosine to the ceramide by condensing a long-chain fatty acid molecule with the base. A fatty acyl-CoA acid acts as donor. Both palmitic and stearic acetyl-CoA [110] may be used for the synthesis of ceramides (see Figs. 3-30 and 3-31). Stearic acid is the predominant fatty acid in brain gangliosides. It forms 72% of the fatty add of shark... 

The processes reponsible of the different levels of polyenoic fatty acids in brain phosphoglycerides, and their possible differential roles in the various lipid classes are largely unknown. The selectively high levels of arachidonic acid in IPG, in the light of the special metabolic properties of this phospholipid in stimulated tissues, appear of possible significance. IPG has been shown to incorporate very actively intracerebrally injected labelled arachidonic acid (Yau Sun, 1974). The incorporation of the radioactivity in all lipid classes was constant by 40 minutes after the injection. 

Brain Coordination of the nervous system Glycolysis, amino acid metabolism Glucose, amino acid, ketone bodies (in starvation) Polyunsaturated fatty acids in neonate Lactate ... 

Chan, P.H. and Fishman, R.A. (1980). Transient formation of superoxide radicals in polyunsaturated fatty acid-induced brain swelling. J. Neurochem. 33, 1004-1007. 

Camp, R.D., Mallet, A.L, Woolard, P.M., Brain, S.D., Kobza-Black, A. and Greaves, M.W. (1983). The identification of hydroxy fatty acids in psoriatic skin. Prostaglandins, 26, 431-447. 

Cortisol-induced lipolysis not only provides substrates for gluconeogenesis (formation of glucose from noncarbohydrate sources) but it also increases the amount of free fatty acids in the blood. As a result, the fatty acids are used by muscle as a source of energy and glucose is spared for the brain to use to form energy. 

Each phospholipid class in a given tissue has a characteristic fatty acid composition. Though the same fatty acid may be present in a number of lipids, the quantitative fatty acid composition is different for each class of lipids and remains fairly constant during the growth and development of the brain. A typical distribution profile of the major fatty acids in rat brain phospholipids is given in Table 3.1. Not only do the phosphoglycerides differ in the structure of the polar head groups, or phospholipid... 

Acetoacetate and 3-hydroxybutyrate are known as ketone bodies. They are classified as fat fuels since they arise from the partial oxidation of fatty acids in the liver, from where they are released into the circulation and can be used by most if not all aerobic tissues (e.g. muscle, brain, kidney, mammary gland, small intestine) (Figure 7.7, Table 7.1). There are two important points (i) ketone bodies are used as fuel by the brain and small intestine, neither of which can use fatty acids (ii) ketone bodies are soluble in plasma so that they do not require albumin for transport in the blood. 

It has been known for some time that omega-3 fatty acids are qnantitatively important components of the membranes of nenrones in the brain. The remarkable nnmber of axons and dendrites that link the neurones in the brain means that the nnmber of membranes in this organ is enormons. The reqnirement for the omega-3 fatty acids in the brain will be high in at least two conditions ... 

In view of these factors, it has been suggested that a deficiency of omega-3 fatty acid in the diet will decrease the concentration of these fatty acids available for synthesis of the required phospholipids in the body, including the brain. If this was a chronic deficiency it could increase the risk of development of some disorders, including depression, schizophrenia and attention deficit syndrome. There is some evidence that this is the case. 

Post mortem studies have shown that the level of polynn-satnrated fatty acids in some areas of the brain is decreased (particnlarly the hippocampus, striatum and cortex). In addition, it is known that the fluidity of membranes in... 

Bourre, J.M., Piciotti, M., Dumont, O., and Durand, G. 1990. Dietary linoleic acid and polyunsaturated fatty acids in rat brain and other organs Minimal requirements of linoleic acid. Lipids 25, 465-472. 

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