Summary
Axonal reaction of motoneurons has been shown to be usually accompanied by an early and brisk proliferation of perineuronal microgliacytes. In order to clarify the real nature of such newly formed microglial satellites and their fine structural relationships to the regenerating nerve cells, facial nuclei from bilateral preparations were examined by light and electron microscopy 4 days after cutting the right facial nerve in rats. On the transected side, microgliacytes could often be observed closely adjoining motoneuron perikarya and main dendrites over long distances, and thereby removing morphologically intact synaptic terminals from the neuronal surface membranes. This displacement of boutons by microglial cells is probably preceded by a loosening of the synaptic contacts due to some unknown membrane changes in the regenerating motoneurons. The functional significance of this considerable deafferentation process could not be entirely elucidated.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Alksne, J. F., T. W. Blackstad, F. Walberg, and L. E. White jr.: Electron microscopy of axon degeneration: A valuable tool in experimental neuroanatomy. Ergebn. Anat. Entwickl.-Gesch. 39, 1–32 (1966).
Armstrong, J., and P. R. Stephens: A modified chrome-silver paraffin wax technique for staining neural endfeet. Stain Technol. 35, 71–75 (1960).
Blinzinger, K.: Elektronenmikroskopische Beobachtungen bei experimentell erzeugter Randzonensiderose des Kaninchengehirns. Zbl. ges. Neurol. Psychiat. 188, 392 (1967); Acta neuropath. (Berl.) (in press).
—, u. H. Hager: Elektronenmikroskopische Untersuchungen über die Feinstruktur ruhender und progressiver Mikrogliazellen im Säugetiergehirn. Beitr. path. Anat. 127, 173–192 (1962).
—: Elektronenmikroskopische Untersuchungen zur Feinstruktur ruhender und progressiver Mikrogliazellen im ZNS des Goldhamsters. Progr. Brain Res. 6, 99–112 (1964).
Bodian, D.: Synaptic types on spinal motoneurons: An electron microscopic study. Bull. Johns Hopk. Hosp. 119, 16–45 (1966).
Burke, R. E.: Physiologic evidence for spatial distribution of group Ia afferent terminals on motoneuron surface. Physiologist 9, 148 (1966).
Cammermeyer, J.: Juxtavascular karyokinesis and microglia cell proliferation during retrograde reaction in the mouse facial nucleus. Ergebn. Anat. Entwickl.-Gesch. 38, 1–22 (1965a).
—: Histiocytes, juxtavascular mitotic cells and microglia cells during retrograde changes in the facial nucleus of rabbits of varying age. Ergebn. Anat. Entwickl.-Gesch. 38, 195–229 (1965b).
Del Rio-Hortega, P.: Microglia. In: W. Penfield (ed.), Cytology and cellular pathology of the nervous system, vol. 2, p. 481–534. New York: P. B. Hoeber 1932.
Friede, R. L., and M. A. Johnstone: Responses of thymidine labeling of nuclei in gray matter and nerve following sciatic transection. Acta neuropath. (Berl.) 7, 218–231 (1967).
Gray, E. G., and V. P. Whittaker: The isolation of synaptic vesicles from the central nervous system. J. Physiol. (Lond.) 153, 35 P-37 P (1960).
Illis, L.: The relative densities of monosynaptic pathways to the cell bodies and dendrites of the cat ventral horn. J. neurol. Sci. 4, 259–270 (1967).
Kreutzberg, G. W.: Autoradiographische Untersuchung über die Beteiligung von Gliazellen an der axonalen Reaktion im Facialiskern der Ratte. Acta neuropath. (Berl.) 7, 149–161 (1966).
—: Über perineuronale Mikrogliazellen — Autoradiographische Untersuchungen. Zbl. ges. Neurol. Psychiat. 188, 387 (1967); Acta neuropath. (Berl.) (in press).
Luft, J. H.: Improvements in epoxy resin embedding methods. J. biophys. biochem. Cytol. 9, 409–414 (1961).
Naoumenko, J., and I. Feigin: A modification for paraffin sections of silver carbonate impregnation for microglia. Acta neuropath. (Berl.) 2, 402–406 (1963).
Palade, G. E.: A study of fixation for electron microscopy. J. exp. Med. 95, 285–298 (1952).
Rapos, M., u. J. Bakos: Veränderungen der Neuroglia im Nucleus originis nervi hypoglossi nach mechanischer Beschädigung des Nervus hypoglossus. Z. mikr.-anat. Forsch. 65, 211–218 (1959).
Rasmussen, G. L.: Selective silver impregnation of synaptic endings. In: W. F. Windle (ed.), New research techniques of neuroanatomy, p. 27–39. Springfield (Ill.): Ch. C. Thomas 1957.
Rewcastle, N. B.: Glutaric acid dialdehyde; a routine fixative for central nervous system electron microscopy. Nature (Lond.) 205, 207–208 (1965).
Reynolds, E. S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol. 17, 208–212 (1963).
Sjöstrand, J.: Proliferative changes in glial cells during nerve regeneration. Z. Zellforsch. 68, 481–493 (1965).
- Glial cells in the hypoglossal nucleus of the rabbit during nerve regeneration. Acta physiol. scand. 67, Suppl. No 270 (1966).
Watson, W. E.: An autoradiographic study of the incorporation of nucleic-acid precursors by neurones and glia during nerve regeneration. J. Physiol. (Lond.) 180, 741–753 (1965a).
—: An autoradiographic study of the incorporation of nucleic-acid precursors by neurones and glia during nerve stimulation. J. Physiol. (Lond.) 180, 754–766 (1965b).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Blinzinger, K., Kreutzberg, G. Displacement of synaptic terminals from regenerating motoneurons by microglial cells. Z. Zellforsch. 85, 145–157 (1968). https://doi.org/10.1007/BF00325030
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00325030