Myelin components

Synthesis of myelin components is very rapid during deposition of myelin 67... 

The composition of myelin changes during development 68 Spontaneous mutations in experimental animals provide insights about the structure and assembly of myelin 68 Myelin components exhibit great heterogeneity of metabolic turnover 69... 

Myelin components exhibit great heterogeneity of metabolic turnover. One of the novel characteristics of myelin demonstrated in early biochemical studies was that its overall rate of metabolic turnover is substantially slower than that of other neural membranes [1]. A standard type of experiment was to evaluate lipid or protein turnover by injecting rat brains with a radioactive metabolic precursor and then follow loss of radioactivity from individual components as a function of time. Structural lipid components of myelin, notably cholesterol, cerebro-side and sulfatide, as well as proteins of compact myelin, are relatively stable, with half-lives of the order of many months. One complication in interpreting these studies is that the metabolic turnover of individual myelin components is multiphasic - consisting of an initial rapid loss of radioactivity followed by a much longer slower loss. 

Using this system, Hamburg (13) could show an acceleration of myelinogenesis by (1,5 to 3 yg/ml) addition. The mechanism whereby influences myelination includes (a) differentiation of the neuroglial cell population responsible for myelin synthesis (38), (b) induction of such differentiated cells to synthesize myelin components, and (c) assembling of the various components to form the complex myelin membrane. Studies are underway to examine the latter possibilities. 

Mpz, myelin Protein Zero Peripheral myelin component, transmembrane cell adhesion KO, Tg... 

Myelinating cells are susceptible to agents that disrupt the synthesis of myelin components, the best example of which is diphtheria toxin, which has access to peripheral nerves where it inhibits Schwann cell protein synthesis and causes primary demyelina-tion. Oligodendrocyte demyelination can be induced experimentally by diphtheria toxin and by other... 

Ptacek But they do have other myelin components. What happens to those ... 

V6. Vlassara, H., Brownlee, M., and Cerami, A., Excessive nonenzymatic glycosylation of peripheral and central nervous system myelin components in diabetic rats. Diabetes 32, 670-674 (1983). 

Estimates of the rate of myelin synthesis can be obtained in vitro from the measurement of cerebroside synthesis, which increases fourfold from day 10 to day 20 in the rat and then slowly decreases along with the overall rate of myelin synthesis. In vivo studies employing radiolabeled precursors of specific myelin components, such as sulfate into sulfatide, yield results similar to those obtained in vitro. In situ studies with tissue slices confirm in vitro and in vivo experiments. These studies also indicate that the appearance of... 

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