Peripheral nervous system myelin

There is a second family of small lipid-binding proteins, the P2 family, which include among others cellular retinol- and fatty acid-binding proteins as well as a protein, P2, from myelin in the peripheral nervous system. However, members of this second family have ten antiparallel p strands in their barrels compared with the eight strands found in the barrels of the RBP superfamily. Members of the P2 family show no amino acid sequence homology to members of the RBP superfamily. Nevertheless, their three-dimensional structures have similar architecture and topology, being up-and-down P barrels. 

The Schwann cell is the myelin-producing cell of the peripheral nervous system 16... 

The Schwann cell is the myelin-producing cell of the peripheral nervous system. When axons leave the CNS, they lose their neuroglial interrelationships and traverse a short transitional zone where they are invested by an astroglial sheath enclosed in the basal lamina of the glia limitans. The basal lamina then becomes continuous with... 

Central nervous system myelin contains some unique proteins 58 Peripheral nervous system myelin also contains unique proteins 63 Some classically defined myelin proteins are common to both peripheral and central myelin 64... 

FIGURE 4-10 Myelin formation in the peripheral nervous system. (A) The Schwann cell has surrounded the axon but the external surfaces of the plasma membrane have not yet fused in the mesaxon. (B) The mesaxon has fused into a five-layered structure and spiraled once around the axon. (C) A few layers of myelin have formed but are not completely compacted. Note the cytoplasm trapped in zones where the cytoplasmic membrane surfaces have not yet fused. (D) Compact myelin showing only a few layers for the sake of clarity. Note that Schwann cell cytoplasm forms a ring both inside and outside of the sheath. (Adapted with permission from Norton, W. T. The myelin sheath. In E. S. Goldensohn and S. H. Appel (eds), Scientific Approaches to Clinical Neurology. Philadelphia Lea Febiger, 1977, pp. 259-298.)... 

Peripheral nervous system myelin also contains unique proteins. 

Stoll, G., Griffin, J. W., Li, C. Y. and Trapp, B. D. Wallerian degeneration in the peripheral nervous system participation of both Schwann cells and macrophages in myelin degradation./. Neurocytol. 18 671-683,1989. 

Oligodendrocytes are present in the CNS as well and wrap around axons to form a myelin sheath. Myelin wraps into concentric layers that spiral around the axon. Gaps in the oligodendrocytes are the nodes of Ranvier, where the membrane maintains contact with extracellular fluid. The nodes serve to propagate the action potential in myelinated axons. Schwann cells perform an analogous function, myelinating axons in the peripheral nervous system. Not all neurons are myelinated, but myelination increases the metabolic efficiency of action potentials. Demyelination of neurons produces deficits in neuronal conduction, as is seen in multiple sclerosis. 

Topilko, P, Schneider-Maunoury, S., Levi, G., Baron-Van Evercooren, A., Chennoufi, A. B., Seitanidou, T., et al. (1994) Krox-20 controls myelination in the peripheral nervous system. Nature 371, 796-799. 

Hu X, Hicks CW, He W, Wong P, Macklin WB, et al. 2006. Bacel modulates myelination in the central and peripheral nervous system. Nat Neurosci 9 1520-1525. 

Myelin Structure in the Central and Peripheral Nervous System. 540... 

The nervous system is particularly susceptible to chemical abuse. Damage to the peripheral nervous system can cause numbness, weakness, and muscle paralysis. Many inhalants have been shown to damage the myelin sheath (Figure 6.1), the protective coat around nerve cells. This causes symptoms like those seen in individuals with multiple sclerosis, including abnormal fatigue, vision problems, loss of muscle coordination, slurred speech, and tremors. Direct damage to the brain... 

Gai bay B, Heape AM, Sai gueil F, Cassagne C (2000) Myelin syndie-sis in die peripheral nervous system. Prog Neurobiol 61 267—304. 

Ogawa-Goto K, Funamoto N, Ohta Y, Abe T, Nagashima K (1992) Myelin gangliosides of human peripheral nervous system An enrichment of GMl in the motor nerve myelin isolated from cauda equina. J Neurochem 59 1844—1849. 

Schwann s ceDs cells that produce myelin in the peripheral nervous system. These cells are located between the axon and axon terminal of neurons and create the myelin sheath which aides in insulating axons and in increasing impulse speeds as they are propagated through the neuron (allowing for salutatory conduction). 

Table 7 lists S-100-positive tumors and their positivity with additional markers. Myelin basic protein (MBP) (30) is a single-chain polypeptide associated with the central and peripheral nervous system. Glial fibrillary acidic protein (GFAP) and neurofilament proteins (NFP) are intermediate filaments associated with glial cells and neural cells, respectively. HMB-45 is a mouse monoclonal antibody that reacts with an antigen present in premelanosomes. It is highly sensitive and specific for melanomas and certain nevi (junctional, congenital, blue nevi). EMA has been discussed in Section 3.1.3.1. 

Tolwani RJ, Cosgaya JM, Varma S, Jacob R, Kuo LE, Shooter EM (2004) BDNF overexpression produces a long-term increase in myelin formation in the peripheral nervous system. J Neurosci Res 77 662-669. 

P2 is a component of myelin from the peripheral nervous system. It is localized on the cytoplasmic side of Schwann cells where it behaves as peripheral membrane protein, although a small amount is found in the cytoplasm (Trapp et al., 1984). Like the other iLBPs, the exact biochemical role of P2 is unknown. Its cellular localization and its ability to bind different fatty acids and retinoids (Uyemura et al., 1984) suggest that it may function in fatty acid trafficking. It would therefore play a major role in the movement of fatty acids between the site of uptake and that of esterification during the massive phospholipid synthesis phase of myelinating Schwann cells. 

Following skin absorption, hexachlorophene enters the nervous system and results in intramyelinic edema, splitting the intraperiod line of myelin in both the central nervous system (CNS) and the peripheral nervous system. Experimental studies with erythrocyte membranes show that hexachlorophene binds tightly to cell membranes, resulting in osmotic swelling of erythrocyte membranes by altering their permeability to sodium and potassium. Hexachlorophene uncouples oxidative phosphorylation. 

Snipes GJ, Suter U, Welcher AA, Shooter EM. Characterization of a novel peripheral nervous system myelin protein (PMP-22/SRI3). J Biol Chem 1992 117 225-38. 

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