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Responses in the hypoglossal nucleus to delayed regeneration of the transected hypoglossal nerve, a quantitative ultrastructural study

Responses in the hypoglossal nucleus to delayed regeneration of the transected hypoglossal nerve,... 221 29 29 2 2 B. E. H. Sumner Department of Physiology University Medical School EH8 9AG Teviot Place Edinburgh Scotland Summary Electron micrographs of the left hypoglossal nucleus of adult male albino rats were quantitatively analyzed from 9–70 days after allowing the transected left hypoglossal nerve to regenerate after an 84 day delay. Delay was achieved by implanting the proximal stump into already innervated sternomastoid muscle, where no regeneration occurred. Regeneration was then allowed by denervating the sternomastoid. During the regenerative period the initially high number of abnormally electron dense perikarya and dendrites decreased to almost normal values, but no cell removal was seen. This suggested that the degenerate appearance of many profiles after prolonged prevention of regeneration, was reversible. The neuropil bouton and dendrite counts, and the numbers of synapsing boutons per dendrite, increased steadily to normal values from the low values of suppressed regeneration. Somatic bouton frequencies, even though already low, decreased further at 32 days, and later increased but not to normal values. The decrease at 32 days coincided with the loss of many subsurface cisterns, and dispersion of Nissl substance, all suggestive of chromatolysis. Later the subsurface cisterns and Nissl substance returned. It was suggested that the delay of complete recovery of somatic bouton frequencies might be because of lack of sensory information from the denervated muscle into which the hypoglossal nerve was regenerating, or because of abnormally low starting values for the recovery phase. Astrocyte (or, occasionally microglial) sheaths persisted along boutonfree perikaryal surfaces. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experimental Brain Research Springer Journals

Responses in the hypoglossal nucleus to delayed regeneration of the transected hypoglossal nerve, a quantitative ultrastructural study

Sumner, B.
Experimental Brain Research , Volume 29 (2) – Aug 1, 1977
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References (20)

Publisher
Springer Journals
Copyright
Copyright © 1977 by Springer-Verlag
Subject
Biomedicine; Neurosciences; Neurology
ISSN
0014-4819
eISSN
1432-1106
DOI
10.1007/BF00237043
Publisher site
See Article on Publisher Site

Abstract

221 29 29 2 2 B. E. H. Sumner Department of Physiology University Medical School EH8 9AG Teviot Place Edinburgh Scotland Summary Electron micrographs of the left hypoglossal nucleus of adult male albino rats were quantitatively analyzed from 9–70 days after allowing the transected left hypoglossal nerve to regenerate after an 84 day delay. Delay was achieved by implanting the proximal stump into already innervated sternomastoid muscle, where no regeneration occurred. Regeneration was then allowed by denervating the sternomastoid. During the regenerative period the initially high number of abnormally electron dense perikarya and dendrites decreased to almost normal values, but no cell removal was seen. This suggested that the degenerate appearance of many profiles after prolonged prevention of regeneration, was reversible. The neuropil bouton and dendrite counts, and the numbers of synapsing boutons per dendrite, increased steadily to normal values from the low values of suppressed regeneration. Somatic bouton frequencies, even though already low, decreased further at 32 days, and later increased but not to normal values. The decrease at 32 days coincided with the loss of many subsurface cisterns, and dispersion of Nissl substance, all suggestive of chromatolysis. Later the subsurface cisterns and Nissl substance returned. It was suggested that the delay of complete recovery of somatic bouton frequencies might be because of lack of sensory information from the denervated muscle into which the hypoglossal nerve was regenerating, or because of abnormally low starting values for the recovery phase. Astrocyte (or, occasionally microglial) sheaths persisted along boutonfree perikaryal surfaces.

Journal

Experimental Brain Research – Springer Journals

Published: Aug 1, 1977

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