Brain tissues composition

It is obvious that one should not expect to find in the literature extensive information regarding the composition of the brains, livers, or even muscles of healthy human individualsespecially so since repeated samples would have to be taken for analysis in order to determine conclusively the importance of inter-individual differences. The best that could be hoped for would be extensive "horizontal" studies relative to the composition of blood, secretions, etc., of individual human specimens and, perhaps, more comprehensive data including tissue composition with respect to animals. However, satisfactory studies of this sort have seldom, if ever, been made. More often than not, such horizontal studies as have been made have not been published in complete enough form to give the kind of information needed to answer the questions which we are considering. 

The carbohydrate content and composition, including the sialic acids of the glycopeptides derived from the Tay-Sachs brain tissues, were found to be the same as those in the normal control although the patterns of gangliosides were markedly different due to excessive accumulation of GM2 in the Tay-Sachs brain (39). 

Phosphorus occurs in nature mainly as the minerals apatite, Ca5(P04)3F, hydroxy-apatite, Ca,r,(P04)3(0H), and tricalcium phosphate (phosphate rock, ranging in composition from Ca3(P04)o to hydroxyapatite). Kydroxy-apatite is the main mineral constituent of the bones and teeth of animals, and complex organic compounds of phosphorus are essential constituents of nerve and brain tissue and of many proteins, and are involved significantly in the metabolic reactions of living organisms. 

The interest in neuronal nAChRs has increased in the past few years and a great number of papers were published on the establishment of the physiology of nAChRs including the determination of type, composition, and number of nAChRs present in different tissues, as well as on their pharmacological properties. The need to understand the functional implications of nAChRs in the human brain arises from several known facts, namelly, the reduced number of nAChRs seen in both Alzheimer s and Parkinson s diseases, the importance of cholinergic defects in particular forms of human epilepsy and the decreased number of hippocampal nicotinic receptors seen in postmorten brain tissue of schizophrenia patients. The presence of nAChRs in lung carcinoma cells and the potential role of nicotine in learning and memory was also reported. 

Block RI, O Leary DS, Ehrhardt JC, Augustinack JC, Ghoneim MM, Arndt S, Hall JA (2000a) Effects of frequent marijuana use on brain tissue volume and composition. Neuroreport 11 491-496... 

The unusual solubility behavior of, for example, the Tay-Sachs brain tissues is due to qualitative and quantitative differences in the composition of the appropriate lipid.211 The isolation and purification of these anomalous gangliosides were carried out similarly to those for the gangliosides of normal tissues, for example, by the method of Folch and coworkers.182 In this method, the brain tissues are extracted with chloroform-methanol-water, the extract is washed with potassium chloride solution, and the extracted material is separated on a column of silicic acid by elution with an increasing concentration of methanol in chloroform. 

Although the sterols of normal adult brain are accounted for almost exclusively by free cholesterol, demyelination as a result, for example, of Wallerian degeneration or multiple sclerosis leads to a loss of cholesterol and the short-lived appearance of cholesterol esters (see Davison and Wajda, 1962). Other abnormalities of brain sterol composition are seen in the swayback lamb and in cerebral tumor tissue. 

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