Selective loss of slow and enhancement of fast Na+ currents in cutaneous afferent dorsal root ganglion neurones following axotomy

Neurobiol Dis. 1995 Apr;2(2):87-96. doi: 10.1006/nbdi.1995.0009.


Voltage-dependent Na+ currents were recorded via patch-clamp from identified adult rat lumbar cutaneous dorsal root ganglion (DRG) neurones using whole-cell and bleb-patch-clamp configurations. Na+ currents in DRG neurones studied 18 days after sciatic nerve ligation were compared with those in control neurones. Control neurones tended to have a singular kinetically slow Na+ current or net Na+ current suggestive of two kinetic varieties of channel in a single neurone. Three changes occurred following axotomy: (1) the peak Na+ current increased significantly, (2) kinetically slow TTX-resistant Na+ current, which predominated in controls, was significantly attenuated or lacking altogether, and (3) a singular, TTX-sensitive kinetically fast form of Na+ current predominated. These findings suggest that as part of the response to axonal injury, DRG neurones increase Na+ channel biosynthesis and/or modify preexisting channels such that their kinetics are accelerated. The results are consistent with the idea that axotomized DRG neurones become hyperexcitable due to the emergence of a high density of kinetically fast, pharmacologically distinguishable, Na+ channels in the membrane.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Axons / physiology*
  • Female
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / physiology*
  • Neurons, Afferent / physiology*
  • Patch-Clamp Techniques
  • Rats
  • Rats, Wistar
  • Skin / innervation*
  • Sodium Channels / physiology*


  • Sodium Channels