Waxman S G, Black J A, Sontheimer H, Kocsis J D
Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA.
Clin Neurosci. 1994;2(3-4):202-10.
Two major glial cell types, the oligodendrocyte (which produces myelin) and the perinodal astrocyte (which contacts the sodium channel-rich axon membrane at the node of Ranvier), collaborate with the axon in forming the central myelinated fiber. Astrocytes have been demonstrated to synthesize voltage-sensitive sodium channels, and in some astrocytes these channels have neuronal properties. A variety of lines of evidence suggest that astrocytes play an important role in the reorganization of the axon membrane following demyelination. Possible functions of astrocytes include the targeting, or anchoring, of ion channels at specific sites within the axon membrane, or the specification of channel characteristics as a result of production of extracellular matrix molecules that interact with the glycosylated dome of sodium channels, or the synthesis of channels that are subsequently transferred to axons. It is also possible that astrocytes participate in ionic homeostasis at the node of Ranvier. A second major glial cell type, the oligodendrocyte, produces myelin during normal development. Morphologic studies have demonstrated that transplantation of myelin-forming cells, or their precursors, can result in the production of myelin with normal structure in the myelin-deprived CNS. In recent physiological studies, the function of axons following myelination by exogenous, transplanted glial cells has been examined. In regions of glial cell transplantation, there are significant increases in conduction velocities that approach normal values. Both of these lines of investigation, on astrocytes and myelin-forming oligodendrocytes/oligodendrocyte precursors, suggest that manipulation of glial cell properties may emerge as a viable strategy for promoting the recovery of conduction in CNS white matter axons following demyelination.
两种主要的神经胶质细胞类型，即少突胶质细胞（产生髓磷脂）和结周星形胶质细胞（在郎飞结处接触富含钠通道的轴突膜），与轴突协作形成中枢有髓纤维。已证明星形胶质细胞能合成电压敏感性钠通道，并且在一些星形胶质细胞中这些通道具有神经元特性。多种证据表明，星形胶质细胞在脱髓鞘后轴突膜的重组中起重要作用。星形胶质细胞的可能功能包括将离子通道靶向或锚定在轴突膜内的特定部位，或者由于产生与钠通道糖基化穹顶相互作用的细胞外基质分子而确定通道特性，或者合成随后转移到轴突的通道。星形胶质细胞也有可能参与郎飞结处的离子稳态。第二种主要的神经胶质细胞类型，即少突胶质细胞，在正常发育过程中产生髓磷脂。形态学研究表明，移植形成髓磷脂的细胞或其前体可导致在缺乏髓磷脂的中枢神经系统中产生结构正常的髓磷脂。在最近的生理学研究中，已经对外源移植的神经胶质细胞髓鞘化后的轴突功能进行了研究。在神经胶质细胞移植区域，传导速度显著增加，接近正常值。关于星形胶质细胞和形成髓磷脂的少突胶质细胞/少突胶质细胞前体的这两条研究路线都表明，操纵神经胶质细胞特性可能成为促进脱髓鞘后中枢神经系统白质轴突传导恢复的可行策略。
