Pannese E, Procacci P, Ledda M, Arcidiacono G, Rigamonti L
Institute of Histology, Embryology and Neurocytology, University of Milan, Italy.
J Neurocytol. 1989 Jun;18(3):295-302. doi: 10.1007/BF01190832.
Tufts of microvilli originating from the internodal cytoplasm of Schwann cells associated with myelinated axons in apparently normal lizard spinal roots have been studied under the electron microscope by means of both single and serial sections. More than one tuft of internodal microvilli may arise from a single Schwann cell. Sometimes mitochondria and more frequently an organelle resembling a multivesicular body with a clear matrix can be found in the Schwann cell cytoplasm underlying a tuft of internodal microvilli. The dimensions (length: 0.4-1.0 microns; diameter: 40-70 nm) and structure of internodal microvilli of the Schwann cell are very similar to those of nodal microvilli of the same cell. Each tuft of internodal microvilli projects towards an adjacent unmyelinated axon which at this site is partly devoid of its own Schwann cell sheath. Thus a single Schwann cell may be related to a myelinated axon and an unmyelinated axon at the same time. Patches of a dense axolemmal undercoating (which could be portions of the cytoskeleton) are present in the unmyelinated axon in close spatial correlation with internodal microvilli. The factors which could induce the formation of internodal microvilli as well as the possible role (or roles) of these microvilli are briefly discussed.
利用单切片和连续切片技术，在电子显微镜下对来自与正常蜥蜴脊髓神经根中有髓轴突相关的施万细胞节间细胞质的微绒毛束进行了研究。单个施万细胞可能产生不止一束节间微绒毛。有时，在一束节间微绒毛下方的施万细胞胞质中可发现线粒体，更常见的是一种细胞器，其类似于具有清晰基质的多囊体。施万细胞节间微绒毛的尺寸（长度：0.4 - 1.0微米；直径：40 - 70纳米）和结构与同一细胞的结间微绒毛非常相似。每束节间微绒毛都朝向相邻的无髓轴突伸出，在此部位，该无髓轴突部分没有其自身的施万细胞鞘。因此，单个施万细胞可能同时与有髓轴突和无髓轴突相关。在无髓轴突中存在致密的轴膜下层（可能是细胞骨架的一部分）斑块，与节间微绒毛在空间上紧密相关。本文简要讨论了可能诱导节间微绒毛形成的因素以及这些微绒毛可能的作用。
