On the association between perinodal astrocytic processes and the node of Ranvier in the C.N.S.
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Associations between the axolemma of nodes of Ranvier in the C.N.S. and perinodal astrocytic processes have been confirmed in the guinea pig spinal cord. Since perinodal astrocytic processes were found to be a consistent feature at such nodes, it is proposed that they represent the C.N.S. analogue of the Schwann cell fingers at P.N.S. nodes. Although they assumed a variety of configurations, perinodal astrocytic processes rarely approached the complexity and regularity of Schwann cell profiles at PNS nodes. The findings are discussed in terms of the relevance between perinodal astrocytes and the maintenance of an electrogenic pump at the node.
KeywordsSpinal Cord Schwann Cell Consistent Feature Cell Profile Astrocytic Process
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- Berthold, C. -H. &Carlstedt, T. (1977) Observations on the morphology at the transition between the peripheral and the central nervous system in the cat.Acta physiologica scandinavica 446, 43–60.Google Scholar
- Bray, G. M., Rasminsky, M. &Aguayo, A. J. (1981) Interactions between axons and their sheath cells.Annual Reviews of Neuroscience 4, 127–62.Google Scholar
- Carlstedt, T. (1977) Observations on the morphology at the transition between the peripheral and the central nervous system in the cat.Acta physiologica scandinavica 446, 61–70.Google Scholar
- Ghabriel, M. N. &Allt, G. (1982) The node of Ranvier.Progress in Anatomy 2, 138–60.Google Scholar
- Hildebrand, C. (1971a) Ultrastructural and light microscopic studies of the nodal region in large myelinated fibres of the feline spinal cord white matter.Acta physiologica scandinavica 364, 43–71.Google Scholar
- Hildebrand, C. (1971b) Ultrastructural and light-microscopic studies of the developing feline spinal cord white matter. I. The nodes of Ranvier.Acta physiologica scandinavica 364, 81–101.Google Scholar
- Hildebrand, C. &Waxman, S. G. (1983) Regional node-like membrane specializations in non-myelinated axons of rat retinal nerve fiber layer.Brain Research 258, 23–32.Google Scholar
- Landon, D. N. (1981) Structure of normal peripheral myelinated nerve fibres. InDemyelinating Disease, Basic and Clinical Electrophysiology Advances in Neurology Vol. 31 (edited byWaxman, S. G. &Ritchie, J. M.), pp. 25–49. New York: Raven Press.Google Scholar
- Peters, A., Palay, S. L. &Webster, H. De F. (1976)The Fine Structure of the Nervous System. Philadelphia: Saunders.Google Scholar
- Raine, C. S. (1977) Morphological aspects of myelin and myelination. InMyelin (edited byMorell, P.), pp. 1–49. New York: Plenum.Google Scholar
- Ritchie, J. M. &Rogart, R. B. (1977) Density of sodium channels in mammalian myelinated nerve fibers and nature of the axonal membrane under the myelin sheath.Proceedings of the National Academy of Sciences USA 74, 211–5.Google Scholar
- Waxman, S. G. &Foster, R. E. (1980) Ionic channel distribution and heterogeneity of the axon membrane in myelinated fibers.Brain Research Reviews 2, 205–34.Google Scholar