| Popis: |
The studies of the mechanisms involved in myelination and myelin compaction constitute a broad field of neurobiology since myelin plays an important role of in conductance of nerve impulse both in central and peripheral nervous system. One of the most dramatic demyelinating diseases is multiple sclerosis (MS). The study of demyelination in MS may help in understanding the molecular mechanisms involved in maintenance of myelin structure. Several hypothesis have been presented for explaining myelin compaction. From the studies of mid mutant (Doolittle and Schwiekart, 1977), it has been proposed (Jacque et al., 1983; Kimura et al., 1985; Lachapelle et al., 1980; Matthieu 1982; Matthieu et al., 1980a; 1980b; 1981; 1984; Mikoshiba et al., 1987; Quarles, 1984; Waehneldt and Linington, 1980) that myelin basic protein (MBP) is involved in the mechanism of myelin compaction at the cytoplasmic surface of the oligodendrocyte membrane. A similar role has been attributed to proteolipid protein (Duncan et al., 1987). Due to the specific defect of MBP in mld mutant there is an absence of the major dense line. It has also been proposed that this adhesion involved interaction of myelin basic protein with negatively charged glycolipids (i.e. sulfatides) present in high amount in these membranes (Zalc et al., 1981). Another possibility was the interaction of MBP with other glycolipids (Ikeda and Yamamoto, 1987). Similarly, the proteolipid protein (PLP) has been suggested to be involved in myelin compaction at the level of extracellular face of the oligodendrocyte (Dautigny et al., 1986). |
