Brain lipids biochemical diversity

As repeatedly stated in this book, the brain is a lipid machine with approximately 50% of its organic matter composed of lipids. To complicate tiie problem, lipids display broad biochemical diversity, allowing endless variations, from the more subtle (e.g., a-hydroxylation of the acyl chain of GalCer) to the more extreme (compare the structure of GTlb with that of cholesterol). To get a better idea of the situation, representative examples of closely related and totally unrelated lipid structures are given in Fig. 4.1. 

The two partners are the membrane and the infectious protein (e.g., Alzheimer s -amyloid peptide Ap, Parkinson s associated a-synuclein, and HIV-1 gpl20) (Fig. 14.1A-C). Each of these proteins faces a complex membrane formed by a collection of lipids with wide biochemical diversity. Hopefully, among the myriad of brain membrane lipids, the protein generally selects a preferred target, most often located in a lipid raft microdomain. For instance, Ap peptides interact preferentially with ganglioside GMl, and a-synuclein with GM3. ... 

Psychotropic effects. Ethanol is unusual in that it is freely soluble in both water and lipids. Thus, it has access to all regions of the highly vascularized brain. Although the molecular basis of ethanol action in the brain is not clear, it is evident that ethanol influences a number of neurotransmitter receptors and ion channels. Suggest a biochemical explanation for the diverse effects of ethanol. 

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