Summary
Myelination was inhibited in the spinal cord of three day-old rats with 2000 rads of X-irradiation. Myelination subsequently occurred as a result of caudal migration of oligodendrocytes and extensive invasion of the cord by Schwann cells. Although oligodendrocytes were present in areas containing Schwann cells, astrocytes were absent. The presence of Schwann cells in the neuropil of the spinal cord did not stimulate production of basement membrane by astrocytes, so no new glial limiting membrane was formed. Evidence is presented which suggests that if astrocytes do not form a glial limiting membrane when opposed by large numbers of Schwann cells they are destroyed by the invading cells. It is suggested that the glial limiting membrane normally inhibits entry of Schwann cells into the central nervous system; if this is destroyed and not reconstituted, Schwann cells can migrate freely into the neuropil.
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Beal, J. A. andHall, J. L. (1974) A light microscopic study of the effects of X-irradiation on the spinal cord of neonatal rats.Journal of Neuropathology and Experimental Neurology 33, 128–43.
Blakemore, W. F. (1973) Remyelination of the superior cerebellar peduncle in the mouse following demyelination induced by feeding cuprizone.Journal of the Neurological Sciences 20, 73–83.
Blakemore, W. F. (1974) Remyelination of the superior cerebellar peduncle on old mice following demyelination induced by cuprizone.Journal of the Neurological Sciences 22, 121–6.
Blakemore, W. F. (1975) Invasion of Schwann cells into the spinal cord of the rat following local injection of lysolecithin.Journal of Neuropathology and Applied Neurobiology, in press.
Blakemore, W. F., Harding, J. D. J. andDone, J. T. (1974) Ultrastructural observations on the spinal cord of a Landrace pig with congenital tremor Type AIII.Research in Veterinary Science 17, 174–8.
Druckman, R. andMair, W. C. P. (1953) Aberrant regenerating nerve fibres in injury to the spinal cord.Brain 76, 448–54.
Feigin, I. andOgata, J. (1971) Schwann cells and peripheral myelin within human central nervous tissue. The mesenchymal character of Schwann cells.Journal of Neuropathology and Experimental Neurology 30, 603–12.
Gilmore, S. A. (1963) The effects of X-irradiation on the spinal cords of neonatal rats. II. Histological observation.Journal of Neuropathology and experimental Neurology 22, 294–301.
Gilmore, S. A. (1971) Autoradiographic studies of intramedullary Schwann cells in irradiated spinal cord of immature rats.Anatomical Record 171, 517–28.
Gilmore, S. A. (1973) Long-term effects of ionizing radiation on the rat spinal cord: Intramedullary connective tissue formation.American Journal of Anatomy 137, 1–18.
Gilmore, S. A. andDuncan, D. (1968) On the presence of peripheral-like nervous and connective tissue within irradiated spinal cord.Anatomical Record 16, 675–90.
Harrison, B. M., McDonald, W. I. andOchoa, J. (1972) Remyelination in the central diphtheria brain lesion.Journal of the Neurological Sciences 17, 293–302.
Hughes, J. T. andBrownell, B. (1963) Aberrant nerve fibres within the spinal cord.Journal of Neurology, Neurosurgery and Psychiatry 26, 528–34.
Meier, C., Herschkowitz, N. andBischoff, A. (1974) Morphological and biochemical observations in the Jimpy spinal cord.Acta Neuropathologica 27, 349–62.
Prineas, J., Raine, C. S. andWiśniewski, H. (1969) An ultrastructural study of demyelination and remyelination. Part 3. Chronic experimental allergic encephalomyelitis in the central nervous system.Laboratory Investigation 21, 472–83.
Windle, W. F., Clemente, C. D. andChambers, W. W. (1952) Inhibition of formation of a glial barrier as a means of permitting a peripheral nerve to grow into brain.Journal of Comparative Neurology 96, 359–70.
Wiśniewski, H. andRaine, C. S. (1971) An ultrastructural study of experimental demyelination and remyelination. Part 5. Central and peripheral nervous system lesions caused by diphtheria toxin.Laboratory Investigation 25, 73–80.
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Blakemore, W.F., Patterson, R.C. Observations on the interactions of Schwann cells and astrocytes following X-irradiation of neonatal rat spinal cord. J Neurocytol 4, 573–585 (1975). https://doi.org/10.1007/BF01351538
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DOI: https://doi.org/10.1007/BF01351538