QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, May 30, 2007, 27(22):6068-6078; doi:10.1523/JNEUROSCI.1442-07.2007

This Article Full Text Full Text (PDF) Supplemental Data Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Related articles in J. Neurosci. Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Tang, X.-Q. Articles by Smith, G. M. Search for Related Content PubMed PubMed Citation Articles by Tang, X.-Q. Articles by Smith, G. M. Pubmed/NCBI databases Substance via MeSH

 Previous Article

Development/Plasticity/Repair
Targeting Sensory Axon Regeneration in Adult Spinal Cord

Xiao-Qing Tang, Paula Heron, Charles Mashburn, and George M. Smith

Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Lexington, Kentucky 40536-0298

Correspondence should be addressed to Dr. George M. Smith, Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Lexington, KY 40536-0298. Email: gmsmith{at}uky.edu

Extensive regeneration of sensory axons into the spinal cord can be achieved experimentally after dorsal root injury, but no effort has been made to target regenerating axons and restore a normal lamina-specific projection pattern. Ectopic axon growth is potentially associated with functional disorders such as chronic pain and autonomic dysreflexia. This study was designed to target regenerating axons to normal synaptic locations in the spinal cord by combining positive and negative guidance molecules. Previously, we observed that, after dorsal rhizotomy, overexpression of NGF leads to robust regeneration and sprouting of calcitonin gene-related peptide (CGRP)-positive nociceptive axons throughout dorsal horn and ventral horns. To restrict these axons within superficial laminas, adenovirus expressing semaphorin 3A was injected into the ventral spinal cord 3 d after NGF virus injection. Semaphorin 3A expression was observed in deep dorsal and ventral cord regions and limited axon growth to laminas I and II, shaping axonal regeneration toward the normal distribution pattern. NGF and semaphorin 3A treatment also targeted the regeneration of substance P-positive nociceptive axons but had no effect on injured isolectin B4-binding nociceptive axons. Axon regeneration led to functional restoration of nociception in both NGF- and NGF/semaphorin 3A-treated rats. Although no significant difference in behavior was found between these two groups, confocal microscopy illustrated ectopic synaptic formations in deeper laminas in NGF/green fluorescent protein-treated rats. The results suggested that antagonistic guidance cues can be used to induce and refine regeneration within the CNS, which is important for long-term, optimal functional recovery.

Key words: semaphorin 3A; nerve growth factor; primary nociceptive axons; regeneration; axon guidance; lamina specific

---

Received Oct. 24, 2006; accepted April 25, 2007.

Correspondence should be addressed to Dr. George M. Smith, Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Lexington, KY 40536-0298. Email: gmsmith{at}uky.edu

Related articles in J. Neurosci.:

This Week in The Journal

J. Neurosci. 2007 27: i. [Full Text]  

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help