Fiber counts at multiple sites along the rat ventral root after neonatal peripheral neurectomy or dorsal rhizotomy

S. Chae Nam, K. Jin Kim, J. Woo Leem, KJ Chung, Jin Chung

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

We hypothesized that the afferent fibers in the ventral root of the rat are the third branches of dorsal root ganglion cells; these afferent processes in the ventral root are of varying length and end bluntly along the length of the root. In the case of an injury at either the central or the peripheral processes of the dorsal root ganglion cells in the neonatal stage, these fibers sprout at the blunt endings along the length of the ventral root. We cut either the sciatic nerve or the dorsal root on one side in neonatal rats. After the rats were fully grown, the number of both myelinated and unmyelinated fibers was counted in electron photomicrographs at multiple sites along the length of the ventral root. We observed a greatly increased number of unmyelinated fibers in the ventral root after the sciatic nerve had been cut at the neonatal stage. The magnitude of increase was more at the distal than at the proximal portion of the ventral root, suggesting that added fibers originated from the distal side. Neonatal dorsal rhizotomy, however, did not produce the same result. These results are consistent with our hypothesis that peripheral nerve injury at the neonatal stage triggers sprouting of the third branches of the dorsal root ganglion cells which end bluntly along the length of the ventral root in the normal animal.

Original languageEnglish (US)
Pages (from-to)336-342
Number of pages7
JournalJournal of Comparative Neurology
Volume290
Issue number3
DOIs
StatePublished - 1989

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Keywords

  • peripheral nerve injury
  • peripheral nerve sprouting
  • spinal nerve
  • unmyelinated fibers
  • ventral root afferents

ASJC Scopus subject areas

  • Neuroscience(all)

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