Summary
The ultrastructure of the cervical cord is described in a new canine mutant with severe hypomyelination of the C.N.S. Axons were either non-myelinated or surrounded by a myelin sheath that was markedly reduced in both its thickness and length of internode. Myelinated and non-myelinated zones were present on a single axon. There was no paucity of oligodendrocytes but many of those present contained empty or granular vacuoles within the cytoplasm. Features suggesting immaturity of myelination were commonly found at paranodes and along the internode. Abnormal inter-relationships of oligodendrocytes and astrocytes were present at many paranodes. These observations suggest an intrinsic defect of oligodendrocyte metabolism such that they are incapable of normal extension of their plasma membranes, while the cytoplasmic vacuoles may represent breakdown of defective lipids.
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References
Blakemore, W. F. &Harding, J. D. D. (1974) Ultrastructural observations on the spinal cords of piglets affected with congenital tremor type AIV.Research in Veterinary Science 17, 248–55.
Bonnaud-Toulze, E. N. &Raine, C. S. (1980) Remodelling during remyelination in the peripheral nervous system.Neuropathology and Applied Neurobiology 6, 279–80.
Ellisman, M. H. (1979) Molecular specilizations of the axon membrane at nodes of Ranvier are not dependent upon myelination.Journal of Neurocytology 8, 719–35.
Fraher, J. P. (1978) Quantitative studies on the maturation of central and peripheral parts of individual ventral motor neuron axons.Journal of Anatomy 126, 509–33.
Griffiths, I. R., Duncan, I. D., McCulloch, M. &Harvey, M. J. A. (1981) Shaking Pups: A disorder of central myelination in the spaniel dog. 1. Clinical, genetic and light microscopic observations.Journal of the Neurological Sciences 50, 423–33.
Hall, S. M. (1973) Some aspects of remyelination after demyelination produced by the intraneural injection of lysophosphatidyl choline.Journal of Cell Science 13, 461–77.
Hildebrand, C. (1971) Ultrastructural and light microscopic studies of developing feline spinal cord white matter. 1. The nodes of Ranvier.Acta physiologica Scandinavia, Suppl.364, 81–108.
Karnovsky, M. J. (1965) A formaldehyde-glutaraldehyde fixative of high osmolality for use in electron microscopy.Journal of Cell Biology 37, 137A.
Karnovsky, M. J. (1971) Use of ferrocyanide-reduced osmium tetroxide in electron microscopy. InAbstracts of Papers Eleventh Annual Meeting American Society of Cell Biology, New Orleans, p. 146.
King, R. H. M., Pollard, J. D. &Thomas, P. K. (1975) Aberrant remyelination in chronic relapsing experimental allergic neuritis.Neuropathology and Applied Neurobiology 1, 367–78.
Morales, R. &Duncan, D. (1975) Specialized contacts of astrocytes with astrocytes and with other cell types in the spinal cord of the cat.Anatomical Record 182, 255–66.
Peters, A., Palay, S. L. &Webster, H. de F. (1970)The Fine Structure of the Nervous System. The Cells and their Processes. New York: Harper and Row.
Privat, A., Jaque, C., Bourne, J. M., Duponey, P. &Baumann, N. (1979) Absence of the major dense line in myelin of the mutant mouse ‘shiverer’.Neuroscience Letters 12, 107–12.
Raine, C. S. (1977) Morphological aspects of myelin and myelination. InMyelin (edited byMorell, P.), pp. 1–49. New York: Plenum Press.
Rosenbluth, J. (1979a) Aberrant axon-Schwann cell junctions in dystrophic mouse nerves.Journal of Neurocytology 8, 655–72.
Rosenbluth, J. (1979b) Freeze fracture of nerve fibres: evidence that regional differentiation of the axolemma depends upon glial contact, InCurrent Topics in Nerve and Muscle Research (edited byAguayo, A. andKarpati, G.), pp. 200–29. Amsterdam: Excerpta Medica.
Schnapp, B., Peracchia, C. &Mugnaini, E. (1976) The paranodal axo-glial junction in the central nervous system studied with thin sections and freeze-fracture.Neuroscience 1, 181–90.
Stirling, C. A. (1975) Abnormalities in Schwann cell sheaths in spinal roots of dystrophic mice.Journal of Anatomy 119, 169–80.
Suzuki, K. &Zagoren, J. C. (1977) Quaking mouse: An ultrastructural study of the peripheralnerves.Journal of Neurocytology 6, 71–84.
Watanabe, I. &Bingle, G. J. (1972) Dysmyelination in ‘Quaking’ mouse electron microscopic study.Journal of Neuropathology and Experimental Neurology 31, 352–69.
Wisniewski, H. &Morrell, P. (1971) Quaking mouse: Ultrastructural evidence for arrest of myelinogenesis.Brain Research 29, 63–73.
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Griffiths, I.R., Duncan, I.D. & McCulloch, M. Shaking pups: a disorder of central myelination in the spaniel dog. II. Ultrastructural observations on the white matter of the cervical spinal cord. J Neurocytol 10, 847–858 (1981). https://doi.org/10.1007/BF01262657
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DOI: https://doi.org/10.1007/BF01262657