Wiley-Livingston C A, Ellisman M H
J Neurocytol. 1982 Feb;11(1):65-80. doi: 10.1007/BF01258005.
We have studied remyelination of rat peripheral nerves after tellurium-induced demyelination using thin section and freeze-fracture techniques. In rats fed a 1% tellurium diet, regions of demyelination were readily identified by myelin debris and the presence of large denuded axons. Remyelination occurred despite continued tellurium ingestion. However, the demyelinated axons underwent a more rapid remyelination if tellurium was removed from the diet. Remyelination proceeded as described for myelination in the normal developing animal. Sites destined to become nodes of Ranvier were identified as patches of intramembranous particles in the axonal E-face. Early terminal loops of the remyelinating Schwann cell were found adjacent to these particle patches. As wrapping proceeded, terminal loops of myelin, along with associated rows of dimeric-particles characteristic of the axonal P-face, were wound into a paranodal location. This winding of the membrane specializations and associated terminal loops resulted in the reformation of morphologically normal paranodes. The size of the nodal E-face particle patch increased in concordance with increases in the number of paranodal loops until an annulus of particles was obtained as seen in the normal node. The thin section and freeze-fracture morphology of remyelinated fibres was indistinguishable from the morphology of control fibres. These observations are discussed with respect to proposed functions of membrane specializations in myelination and nerve conduction.
我们使用薄切片和冷冻蚀刻技术研究了碲诱导脱髓鞘后大鼠周围神经的髓鞘再生。在喂食含1%碲饮食的大鼠中，脱髓鞘区域可通过髓鞘碎片和大量裸露轴突的存在轻易识别。尽管持续摄入碲，髓鞘再生仍会发生。然而，如果从饮食中去除碲，脱髓鞘轴突会经历更快的髓鞘再生。髓鞘再生过程与正常发育动物中髓鞘形成的描述一致。注定成为郎飞结的部位在轴突E面被识别为膜内颗粒斑块。在这些颗粒斑块附近发现了正在进行髓鞘再生的施万细胞的早期终末环。随着包裹过程的进行，髓鞘的终末环以及轴突P面特有的相关二聚体颗粒排被缠绕到旁结位置。膜特化结构和相关终末环的这种缠绕导致形态正常的旁结重新形成。节点E面膜内颗粒斑块的大小随着旁结环数量的增加而增加，直到获得正常节点中所见的颗粒环。再生髓鞘纤维的薄切片和冷冻蚀刻形态与对照纤维的形态无法区分。我们结合髓鞘形成和神经传导中膜特化结构的假定功能对这些观察结果进行了讨论。
