Development of axonal membrane specializations defines nodes of Ranvier and precedes Schwann cell myelin elaboration.
Development of axonal membrane specializations defines nodes of Ranvier and precedes Schwann cell myelin elaboration.
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轴突膜特化的发展定义了朗飞结，并先于雪旺细胞髓磷脂的形成。
DOI：
10.1016/0012-1606(80)90120-7
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发表时间：
1980
影响因子：
2.7
通讯作者：
Ellisman,MH
中科院分区：
文献类型：
--
作者：
Wiley-Livingston,C;Ellisman,MH
兰氏结的发展以前已经描述了使用薄切片电子显微镜。使用冷冻断裂，我们已经研究了神经胶质细胞和轴突膜专业化的发展之前和髓鞘形成过程中。新生大鼠的脊神经根由成束的无髓和部分有髓轴突组成。在发育的早期阶段，轴突被许旺细胞吞噬，而某些轴突与髓鞘细胞分离成一对一的关系。形状均匀的150- 300微米颗粒的补丁很容易区分相对非颗粒轴突E面。在轴突P面发现不太均匀的颗粒补丁，然而，它们很难与颗粒背景区分开来。薄的过程被发现紧密地应用到轴突膜上的颗粒补丁的两侧。当雪旺氏细胞以一个或两个非致密的绕组吞噬轴突时，它主要局限于这种颗粒斑块的一侧。随着覆盖轴突的缠绕数量的增加，颗粒补丁的大小也会增加，直到观察到类似于成年节点的颗粒环。轴膜中孤立颗粒斑块的缺乏表明，许旺细胞对轴突的识别和分离之后是髓鞘形成的快速启动。在髓鞘形成的早期阶段，有证据表明，在节膜的内吞和外吞事件与轴膜中的230-β二聚体颗粒的出现有关。尽管缺乏绕组和完全没有压实，神经胶质和轴突膜的断裂面显示出线性组织的颗粒。扇形区域的P面的节轴膜显示二聚体颗粒行定向沿着扇形。这些行采用更多的圆周方向时，覆盖的神经胶质过程是一个paranodal位置缠绕。虽然二聚体颗粒行的间距保持在恒定的360 μ m，但每个扇贝的行数必然会随着结旁环的压实而减少，直到达到类似于成虫的状态，其中每个扇贝大约有两行。在轴突和雪旺细胞之间的紧密并列的区域中，在胶质细胞断裂面中的160-和75-μ m颗粒的线性排列发生在胶质细胞环之间的紧密连接的出现之前和压实之前。虽然大多数节点两侧的副阳极对称发展，但也观察到一些不对称的半节点。
The development of the node of Ranvier has been previously described using thin-section electron microscopy. Using freeze-fracture, we have examined the development of glial and axonal membrane specializations before and during myelination. The spinal roots of the newborn rat are composed of bundles of unmyelinated and partially myelinated axons. At this early stage of development, the axons are engulfed by Schwann cells, while certain axons are segregated into a one to one relationship with myelinating cells. Patches of uniformly shaped 150- to 300-Å particles are readily distinguished against a relatively nonparticulate axonal E face. Patches of less uniform particles are found in the axonal P face, however, they are difficult to distinguish from a particulate background. Thin processes are found closely applied to the axonal membrane on the sides of a particle patch. While engulfing the axon with one or two noncompacted windings, the Schwann cell is predominantly restricted to one side of such a particle patch. As the number of windings covering the axon increases, so does the size of the particle patch, until an annulus of particles, similar to that of an adult node, is observed. The paucity of isolated particle patches in axolemma suggests that recognition and segregation of axons by Schwann cells are followed by a rapid initiation of myelination. Throughout the early periods of myelination there is evidence of endocytotic and exocytotic events at the nodal membrane associated with the appearance of 230-Å dimeric particles in the axolemma. Despite the paucity of windings and complete absence of compaction, the fracture faces of the glial and axonal membranes show linear organizations of particles. Scalloped regions in the P face of the nodal axolemma display dimeric-particle rows oriented along the scallop. These rows adopt a more circumferential orientation when the overlying glial process is wound into a paranodal location. While the spacing of dimeric-particle rows is maintained at a constant 360 Å, the number of rows per scallop necessarily decreases with compaction of the paranodal loops until a state similar to that of the adult, in which there are approximately two rows per scallop, is reached. In regions of close apposition between axon and Schwann cell, a linear arrangement of 160- and 75-Å particles in the glial fracture faces occurs prior to the appearance of tight junctions between glial loops and prior to compaction. Though the paranodes on each side of most nodes observed developed symmetrically, some asymmetric half-nodes have been observed.
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猫脊髓白质纤维中髓磷脂周期与髓磷脂层数之间相关性的证据
DOI：
--
发表时间：
1972
期刊：
Journal of Neurocytology
影响因子：
--
作者：
C. Hildebrand
通讯作者：
C. Hildebrand
大鼠坐骨神经髓鞘形成：营养不良与胆固醇生物合成抑制的比较
影响因子：
3.2
作者：
E. Hedley‐Whyte
通讯作者：
E. Hedley‐Whyte
培养中突触连接发育过程中神经炎生长锥和靶神经元的形态变化
影响因子：
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作者：
R. Rees;M. Bunge;R. Bunge
通讯作者：
R. Bunge
发育中的细胞表面的冷冻断裂研究。
影响因子：
7.8
作者：
Elizabeth D. Hay
通讯作者：
Elizabeth D. Hay
DOI：
10.1016/s0022-5320(65)80053-3
发表时间：
1965-01-01
期刊：
JOURNAL OF ULTRASTRUCTURE RESEARCH
影响因子：
--
作者：
CRAVIOTO, H
通讯作者：
CRAVIOTO, H