Lipids in brain

Membrane lipids in brain contain high levels of polyunsaturated fatty acid side chains that are prone to free radical attack. 

Sjovall P, Lausmaa J, Johansson B (2004) Mass spectrometric imaging of lipids in brain tissue. Anal Chem 76 4271 1278. doi 10.1021/ac049389p... 

Adibhatla, R. M. and Hatcher, J. F. Role of lipids in brain injury and diseases. Future Lipidol 2 (2007) 403 22. 

Chen, Y., et al. (2008) Imaging MALDI mass spectrometry using an oscillating capillary nebulizer matrix coating system and its application to analysis of lipids in brain from a mouse model of Tay-Sachs/Sandhoff disease. Analytical Chemistry, 80, 2780-2788. 

The levels of monoenoic lipids in brain are reduced in phenylketonuric patients, and it has been postulated that the absence of phenylalanine hydroxylase is associated with reduced levels of fatty acid desaturase. The desaturase is truly a mono-oxygenase, but there is no indication that mono-oxygenases are generally depressed in phenylketonuria. 

Changes in the fatty acid composition of structural lipids in brain membranes have been reported to modify (Na+K)-ATPase in synaptosomes (Sun Sun, 1975) and n-6 and n-3 fatty acids are considered important for the activity of certain membrane-bound enzymes (Bernsohn Spitz, 1974). Modifications in learning... 

Fig. 5. The accumulation of sphingosine containing lipids in brain tissue. Mouse brain, data estimated from graph presented by Folch (1955) for whole tissue (points are calculated) Rat brain, whole tissue (Burton, unpublished) Human brain, cortex or white as noted (Cumings et al. 1958)...

The net result of these turnover studies is to show that lipids in brain are a part of the dynamic biochemistry of the body — even though they may function primarily as structural components. These data strongly suggest that considerable caution must be exerted in the interpretation of isotopic experiments conducted in vivo, especially when complex compounds are being studied. It emphasizes the need to know more than the radioactivity in the lipid. Other perimeters, such as pool sizes, turnover rates of the pools themselves, permeability, cellular barriers (such as the blood-brain barrier) and other related factors must be determined before a full explanation of the isotope data can be made. 

The book has been written to provide a hands-on approach for neuroscience graduate students. Biochemical structures are dissected and explained with molecular models. Moreover, we propose a step-by-step guide to memorize and draw the biochemical structure of brain lipids, including cholesterol and complex gangliosides. To conclude the book, we present new ideas that can drive innovative tiierapeutic strategies based on the knowledge of the role of lipids in brain disorders. 

The results of Fig,6 are of particular interest, since they might suggest the existence of a new and important pathway for choline plasmalogen synthesis in brain. The mechanisms for the formation of this lipid in brain are in fact stiU unknown, in contrast to v4iat is known about ethanolamine plasmalogen synthesis. 

Ethanol and choline glycerolipids were isolated from calf brain and beef heart lipids by PTLC using silica gel H plates. Pure ethanol amine and choline plasmalogens were obtained with a yield of 80% [74]. Four phosphohpid components in the purple membrane (Bacteriorhodopsin) of Halobacterium halobium were isolated and identified by PTLC. Separated phosphohpids were add-hydrolyzed and further analyzed by GC. Silica gel G pates were used to fractionate alkylglycerol according to the number of carbon atoms in the aliphatic moiety [24]. Sterol esters, wax esters, free sterols, and polar lipids in dogskin hpids were separated by PTLC. The fatty acid composition of each group was determined by GC. 

Kramer, S. D. Hurley, J. A. Abbott, N. J. Begley, D. J., Lipids in blood-brain barrier models in vitro I TLC and HPLC for the analysis of hpid classes and long polyunsaturated... 

Kim, WS, Weickert, CS, and Gamer, B, 2008. Role of ATP-binding cassette transporters in brain lipid transport and neurological disease. JNeurochem 104, 1145-1166. 

This assay has been used by some authors to evaluate the in vitro effects of antioxidant extracts on LDL oxidation (Viana and others 1996 Cirico and Omaye 2006 Kedage and others 2007 Vayalil 2002 Garcfa-Alonso and others 2004 Tarwadi and Agte 2005). Oboh and others (2007) confirmed that hot pepper prevents in vitro lipid peroxidation in brain tissues. Indeed, Bub and others (2000) demonstrated that a moderate intervention with vegetable products rich in carotenoids reduces lipid peroxidation in men. Nicolle and others (2003) evaluated the effect of carrot intake on antioxidant status in cholesterol-fed rats. Later on, they showed that lettuce consumption improves cholesterol metabolism and antioxidant status in rats (Nicole and others 2004). 

Oboh G, Puntel RL and Rocha JBT. 2007. Hot pepper (Capsicum annuum, Tepin and Capsicum Chinese, Habanero) prevents Fe2+-induced lipid peroxidation in brain—in vitro. Food Chem 102(1) 178—185. 

The administration of Qio or quercetin to rats protected against endotoxin-induced shock in rat brain [252]. It was found that the pretreatment with these antioxidants diminished the shock-induced increase in brain MDA and nitric oxide levels. Interesting data have been obtained by Yamamura et al. [253] who showed that ubiquinone Qi0 is able to play a double role in mitochondria. It was found that on the one hand, Q10 enhanced the release of hydrogen peroxide from antimycin A- or calcium-treated mitochondria, but on the other hand, it inhibited mitochondrial lipid peroxidation. It was proposed that Q10 acts as a prooxidant participating in redox signaling and as an antioxidant suppressing permeability transition and cytochrome c release. 

Sanders et al. [133] found that although quercetin treatment of streptozotocin diabetic rats diminished oxidized glutathione in brain and hepatic glutathione peroxidase activity, this flavonoid enhanced hepatic lipid peroxidation, decreased hepatic glutathione level, and increased renal and cardiac glutathione peroxidase activity. In authors opinion the partial prooxidant effect of quercetin questions the efficacy of quercetin therapy in diabetic patients. (Antioxidant and prooxidant activities of flavonoids are discussed in Chapter 29.) Administration of endothelin antagonist J-104132 to streptozotocin-induced diabetic rats inhibited the enhanced endothelin-1-stimulated superoxide production [134]. Interleukin-10 preserved endothelium-dependent vasorelaxation in streptozotocin-induced diabetic mice probably by reducing superoxide production by xanthine oxidase [135]. 

Lipids have multiple functions in brain 33 Membrane lipids are amphiphilic molecules 34... 

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