Oligodendroglial ensheathment of axons during myelination in the developing rat central nervous system. A serial section electron microscopical sttudy
| Autor: | Mary Laurencin, Jerome G. Stempak, Robert L. Knobler |
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| Rok vydání: | 1974 |
| Předmět: |
Models
Anatomic Cytoplasm Central nervous system Serial section Biology White matter Myelin formation Myelin medicine Animals Axon Molecular Biology Myelin Sheath Staining and Labeling Anatomy Hydrogen-Ion Concentration Axons Rats Microscopy Electron Oligodendroglia medicine.anatomical_structure Spinal Cord Mesaxon Female Neuroglia |
| Zdroj: | Journal of ultrastructure research. 49(1) |
| ISSN: | 0022-5320 |
| Popis: | Analysis of serial section electron micrographs of 5 day old rat lumbar spinal cord white matter reveals several new structural features related to the distribution of ensheating cytoplasm and membrane compaction during myelin formation along a developing internode. (1) There is variation in the length, and thus, the number of turns of the mesaxon around the axon at different levels along the length of the internode, providing a different number of layers of ensheating cytoplasm at different levels along the length of the internode. (2) The position of the leading edge of both the inner and outer layers of the ensheating spiral is observed at different points around the axonal circumference when comparison is made between different levels within the same internode. Items 1 and 2 thus suggest that both the inner and outer layers can migrate to provide the initial layers of ensheathment. (3) Observation of the initial stages of myelin compaction include the first observation of the occurrence of both an intraperiod line and a major dense line at separate areas within the same developing internode. (4) While the features described above refer primarily to simple forms of ensheathment by spirals of oligodendroglial cytoplasm, there are also more complicated forms of ensheathment. These have been shown to have one or more wormlike oligodendroglial processes taking origin from one of the spirally arranged layers ensheating the axon. Several “vermicular processes” are described, which extend variable distances from their origin. |
| Databáze: | OpenAIRE |
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