Denervation‐induced intraspinal synaptogenesis of calcitonin gene‐related peptide containing primary afferent terminals

D. L. McNeill, S. M. Carlton, R. E. Coggeshall, C. E. Hulsebosch

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


The purpose of the present study is to provide evidence that chronic spinal denervation leads to an increase in numbers of synaptic terminals from a specific population of primary afferent fibers. Rats were unilaterally deafferented for 35 days (chronic denervation) by dorsal rhizotomies performed from T2 to T8 and T10 to L5, which isolates or spares the T9 root. The contralateral T9 root was spared by similar surgery 5 days (acute denervation) prior to sacrifice. The survival time on the chronic side presumably allows sprouting of T9 primary afferents to occur, whereas the time on the acute side does not. The terminals were labeled with calcitonin gene‐related peptide (CGRP), which is a compound that labels a specific population of primary afferent fibers and terminals, and stereological methods were used to determine the numbers of immunolabeled terminals in laminae I and IIo on the chronic and acute sides of the T9 spinal cord. The findings are that the chronic side had approximately twice as many terminals as the acute side. This difference is statistically significant. These findings are compatible with the hypothesis that chronic denervation leads to synaptogenesis from surviving primary afferent fibers.

Original languageEnglish (US)
Pages (from-to)263-268
Number of pages6
JournalJournal of Comparative Neurology
Issue number2
StatePublished - Jun 8 1990


  • calcitonin gene‐related peptide
  • dorsal rhizotomy
  • presynaptic terminals
  • spinal cord
  • synaptogenesis

ASJC Scopus subject areas

  • General Neuroscience


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