Pre-treatment with lidocaine suppresses ectopic discharges and attenuates neuropeptide Y and c-Fos expressions in the rat cuneate nucleus following median nerve transection

J Chem Neuroanat. 2009 Sep;38(1):47-56. doi: 10.1016/j.jchemneu.2009.03.003. Epub 2009 Mar 27.

Abstract

Following peripheral nerve injury, lidocaine application has been demonstrated to suppress injury discharges. However, there is very little information about the effects of lidocaine pre-treatment. The aim of the present study was to examine the effects of pre-treatment with lidocaine on injury discharges of the nerve, and neuropeptide Y (NPY) and c-Fos expression in the cuneate nucleus (CN) after median nerve transection (MNT). Rats received either saline or 1%, 5%, or 10% lidocaine applied topically to the median nerve before nerve transection. Electrophysiological recording was used to examine the changes in injury discharges of the nerve at post-injection, transection, pre- and post-electrical stimulation stages in the different groups. Sequential immunohistochemistry was also used to identify the number of NPY-like immunoreactive (NPY-LI) fibers and c-Fos-LI cells in the corresponding CN. An increasing frequency of injury discharges was observed at all stages in the pre-saline group, which were suppressed by lidocaine pre-treatment in a dose-dependent manner. Lidocaine pre-treatment also attenuated the number of injury-induced NPY-LI fibers and c-Fos-LI neurons within the CN in a dose-dependent manner. Furthermore, expression of c-Fos-LI neurons in the CN was significantly reduced by an NPY receptor antagonist, indicating that NPY modulated c-Fos expression following MNT. These data suggest that preventing injury discharges with lidocaine pre-treatment can effectively attenuate central sensitization following MNT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Afferent Pathways / injuries
  • Afferent Pathways / metabolism*
  • Afferent Pathways / surgery
  • Anesthetics, Local / pharmacology
  • Animals
  • Cell Count
  • Dose-Response Relationship, Drug
  • Evoked Potentials, Somatosensory / drug effects
  • Evoked Potentials, Somatosensory / physiology
  • Immunohistochemistry
  • Lidocaine / pharmacology*
  • Male
  • Median Nerve / injuries
  • Median Nerve / metabolism*
  • Median Nerve / surgery
  • Medulla Oblongata / anatomy & histology
  • Medulla Oblongata / metabolism*
  • Neural Conduction / drug effects
  • Neural Conduction / physiology
  • Neuropeptide Y / metabolism*
  • Proto-Oncogene Proteins c-fos / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, G-Protein-Coupled / antagonists & inhibitors
  • Receptors, G-Protein-Coupled / metabolism
  • Receptors, Neuropeptide / antagonists & inhibitors
  • Receptors, Neuropeptide / metabolism
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology

Substances

  • Anesthetics, Local
  • Neuropeptide Y
  • Npy1r protein, rat
  • Proto-Oncogene Proteins c-fos
  • Receptors, G-Protein-Coupled
  • Receptors, Neuropeptide
  • Lidocaine