Peptide accumulations in proximal endbulbs of transected axons

Douglas W. Zochodne, Chu Cheng, Marcel Miampamba, Kenneth Hargreaves, Keith A. Sharkey

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Axons proximal to a transection develop into enlarged, but presumed 'passive' endbulb structures. In previous studies, we observed that proximal stumps of transected sciatic nerves accumulate discrete and striking deposits of calcitonin gene-related peptide (CGRP) that have apparent direct and local actions on nearby microvessels. In this work, we provide evidence that CGRP, in the company of several additional peptides, are deposited through 'arrested' anterograde transport into axon endbulbs that develop after transection. In proximal stump tips of rat sciatic nerves transected 48 h earlier, CGRP accumulation colocalized with a label for neurofilament that was accentuated at axon tips, but was prevented by a concurrent more proximal sciatic section. Similarly, interruption of CGRP deposition eliminated its apparent actions on local microvessels following injury. CGRP accumulation was also observed in sural nerve proximal stump tips, indicating its presence in sensory axons despite the known declines in the sensory neuronal synthesis of CGRP that occur following axotomy. Peptide accumulation was not unique to CGRP, with a similar pattern of anterograde accumulation observed for substance P (SP), neuropeptide Y (NPY) and galanin. Deposited peptides and perhaps other axonal constituents in the milieu of a peripheral nerve injury may be associated with important local physiological actions in the regenerative microenvironment.

Original languageEnglish (US)
Pages (from-to)40-50
Number of pages11
JournalBrain Research
Volume902
Issue number1
DOIs
StatePublished - May 25 2001

Keywords

  • Calcitonin gene-related peptide
  • Nerve blood flow
  • Nerve injury
  • Neuropeptides
  • Peripheral nerve

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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