Upregulation of the T-type calcium current in small rat sensory neurons after chronic constrictive injury of the sciatic nerve

J Neurophysiol. 2008 Jun;99(6):3151-6. doi: 10.1152/jn.01031.2007. Epub 2008 Apr 16.


Recent data indicate that peripheral T-type Ca2+ channels are instrumental in supporting acute pain transmission. However, the function of these channels in chronic pain processing is less clear. To address this issue, we studied the expression of T-type Ca2+ currents in small nociceptive dorsal root ganglion (DRG) cells from L4-5 spinal ganglia of adult rats with neuropathic pain due to chronic constrictive injury (CCI) of the sciatic nerve. In control rats, whole cell recordings revealed that T-type currents, measured in 10 mM Ba2+ as a charge carrier, were present in moderate density (20 +/- 2 pA/pF). In rats with CCI, T-type current density (30 +/- 3 pA/pF) was significantly increased, but voltage- and time-dependent activation and inactivation kinetics were not significantly different from those in controls. CCI-induced neuropathy did not significantly change the pharmacological sensitivity of T-type current in these cells to nickel. Collectively, our results indicate that CCI-induced neuropathy significantly increases T-type current expression in small DRG neurons. Our finding that T-type currents are upregulated in a CCI model of peripheral neuropathy and earlier pharmacological and molecular studies suggest that T-type channels may be potentially useful therapeutic targets for the treatment of neuropathic pain associated with partial mechanical injury to the sciatic nerve.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Calcium Channels, T-Type / metabolism*
  • Constriction
  • Dose-Response Relationship, Drug
  • Dose-Response Relationship, Radiation
  • Electric Stimulation
  • Female
  • Ganglia, Spinal / pathology*
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Membrane Potentials / radiation effects
  • Neurons, Afferent / classification
  • Neurons, Afferent / metabolism*
  • Nickel / pharmacology
  • Patch-Clamp Techniques
  • Rats
  • Rats, Sprague-Dawley
  • Sciatic Neuropathy / etiology
  • Sciatic Neuropathy / pathology*
  • Up-Regulation / physiology*


  • Calcium Channels, T-Type
  • Nickel