Injury-associated induction of GAP-43 expression displays axon branch specificity in rat dorsal root ganglion neurons

J Neurobiol. 1993 Jul;24(7):959-70. doi: 10.1002/neu.480240709.


Peripheral nerve injury results in the increased synthesis and axonal transport of the growth-associated protein GAP-43 in dorsal root ganglion (DRG) neurons, coincident with regenerative growth of the injured peripheral axon branches. To determine whether the injury-associated signalling mechanism which leads to GAP-43 induction also operates through the central branches of DRG axons, we used immunocytochemistry to compare the expression of GAP-43 in adult rat DRG neurons 2 weeks after dorsal root crush lesions (central axotomy) or peripheral nerve crush lesions (peripheral axotomy). In uninjured ganglia, a subpopulation of smaller DRG neurons expresses moderate levels of GAP-43, whereas larger neurons generally do not. At 2 weeks following peripheral axotomy, virtually all axotomized neurons, large and small, express high levels of GAP-43. At 2 weeks following dorsal root lesions, no increase in GAP-43 expression is detected. Thus, the injury-associated up-regulation of GAP-43 expression in DRG neurons is triggered by a mechanism that is responsive to injury of only the peripheral, and not the central, axon branches. These findings support the hypothesis that GAP-43 induction in DRG neurons is caused by disconnection from peripheral target tissue, not by axon injury per se.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / immunology
  • Axons / metabolism*
  • GAP-43 Protein
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / metabolism*
  • Immunohistochemistry
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / immunology
  • Nerve Crush
  • Nerve Tissue Proteins / biosynthesis*
  • Nerve Tissue Proteins / immunology
  • Neurons / immunology
  • Neurons / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Sciatic Nerve / physiology


  • GAP-43 Protein
  • Membrane Glycoproteins
  • Nerve Tissue Proteins