CELLULAR MECHANISM OF MYELINATION IN THE CENTRAL NERVOUS SYSTEM
CELLULAR MECHANISM OF MYELINATION IN THE CENTRAL NERVOUS SYSTEM
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DOI：
10.1083/jcb.4.5.651
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发表时间：
1958-01-01
期刊：
影响因子：
--
通讯作者：
WALD, F
中科院分区：
文献类型：
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作者：
DEROBERTIS, E;GERSCHENFELD, HM;WALD, F
用电子显微镜对幼年大鼠和猫的脊髓髓鞘形成进行了研究。在纵切面和横切面上，观察到生长轴突与少突胶质细胞的密切联系。早期裸露的轴突似乎嵌入在少突胶质细胞的细胞质和突起中，它们仅受这两种成分的紧密相对的膜(轴突-寡细胞膜)的限制。在横切面上，可观察到多个轴突位于单个少突胶质细胞内。髓鞘形成的过程是在少突胶质细胞的细胞质内和轴突周围铺设同心的膜性髓鞘层。这些层中的第一层沉积在距离轴突-寡细胞膜一定距离(200到600安或更远)的地方。这种膜和所有其他随后形成的膜具有较高的电子密度，显然是由少突胶质细胞胞质内大量存在的小泡(200-800A)和膜的结合和融合形成的。在早期，髓鞘层可能是不连续的，一些囊泡物质甚至可能被夹在其中，或者夹在髓鞘本身和轴突-寡细胞膜之间。然后，当第8至第10层沉积时，板层的完全结合和排列导致髓鞘的特征有序的多层组织。中枢神经系统髓鞘形成是少突胶质细胞胞浆内膜合成的过程，而不是Geren‘S关于周围神经纤维的假设所假定的质膜包裹的结果，目前正在研究雪旺细胞质参与周围髓鞘形成的可能性。
A study of myelination with electron microscopy has been carried out on the spinal cord of young rats and cats. In longitudinal and transverse sections the intimate relationship of the growing axons with the oligodendrocytes was observed. Early naked axons appear to be embedded within the cytoplasm and processes of the oligodendrocytes from which they are limited only by the intimately apposed membranes of both elements (axon-oligocytic membrane). In a transverse section several axons are observed to be in a single oligodendrocyte. The process of myelination consists in the laying down, within the cytoplasm of the oligodendrocyte and around the axon, of concentric membranous myelin layers. The first of these layers is deposited at a certain distance (200 to 600 A or more) from the axon-oligocytic membrane. This and all the other subsequently formed membranes have higher electron density and are apparently formed by the coalescence and fusion of vesicles (of 200 to 800 A) and membranes found in large amounts within the cytoplasm of the oligodendrocytes. At an early stage the myelin layers may be discontinous and some vesicular material may even be trapped among them or between the myelin proper and the axon-oligocytic membrane. Then, when the 8th to 10th layer is deposited, the complete coalescence and alignment of the lamellae leads to the characteristic orderly multilayered organization of the myelin sheath. Myelination in the central nervous system appears to be a process of membrane synthesis within the cytoplasm of the oligodendrocyte and not a result of the wrapping of the plasma membranes as postulated in Geren''s hypothesis for the peripheral nerve fibers. The possible participation of Schwann cell cytoplasm in peripheral myelination is now being investigated.