Specialized paranodal and interparanodal glial-axonal junctions in the peripheral and central nervous system: A freeze-etching study
| Autor: | R.B. Livingston, K. Akert, H. Moor, K. Pfenninger |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Intercellular cleft
Cytoplasm Superior Colliculi Thin section Central nervous system Neural Conduction Biology Ranvier's Nodes medicine Animals Spinal Cord Ventral Horn Peripheral Nerves Axon Columbidae Molecular Biology Myelin Sheath Leaflet (botany) Freeze Etching General Neuroscience Cell Membrane Saltatory conduction Gap junction Haplorhini Anatomy Axons Rats Microscopy Electron Intercellular Junctions medicine.anatomical_structure Spinal Cord nervous system Cats Neurology (clinical) Anura Neuroglia Developmental Biology |
| Zdroj: | Brain Research. 58:1-24 |
| ISSN: | 0006-8993 |
| Popis: | Summary Analysis has been made of glial-axonal junctions (GAJ) using freeze-etching technics in conjunction with thin section electron micrography. Tissues included spinal cord ventral horn of rat and cat, pigeon optic tectum and peripheral nerves of frog and monkey. An extensive and probably unique union is established between glia and axon throughout the entire region of juxtaposition of glial cytoplasm-containing loops with the axon. The structure is characterized by parallel bands 25–30 nm in width on the axonal outer leaflet, and similarly spaced rows of particles and tiny indentations on the corresponding glial outer leaflet. The glial particles, about 10 nm in diameter, are assumed to cross the narrow intercellular cleft which ranges from 2 nm to 3 nm in width and to attach to the axonal outer leaflet. Two additional patterns are identifiable on the axonal outer leaflet: (1) diagonal features which have 6–7 nm center-to-center spacing which bear angles of 45°-60° in relation to the direction of the bands; and (2) oval subunits, 4 of which compose the diagonal crossing of each band and which are apparently moulded into the axonal outer leaflet. The distance separating the rows of glial particles corresponds to the width of the diagonal features and suggests that the glial particles may be attached to the axon in a regular relationship to these diagonal features. A comparison is ,ade netweem GAJs amd ptjer specialized intercellular contacts, especially septate and gap junctions. The discussion includes consideration of a dynamic role of the GAJ in relation to saltatory conduction, and with respect to other transactions between the two species of cells. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|