Evidence that pregabalin reduces neuropathic pain by inhibiting the spinal release of glutamate

J Neurochem. 2010 Apr;113(2):552-61. doi: 10.1111/j.1471-4159.2010.06625.x. Epub 2010 Jan 28.

Abstract

Pregabalin is an anti-convulsant that successfully treats many neuropathic pain syndromes, although the mechanism of its anti-hyperalgesic action remains elusive. This study aims to help delineate pregabalin's anti-hyperalgesic mechanisms. We assessed the effectiveness of pregabalin at decreasing mechanical and cold hypersensitivity induced in a rat model of neuropathic pain. Thus, we compared the effectiveness of pre- or post-treatment with systemic or intrathecal (i.t.) pregabalin at reducing the development and maintenance of the neuropathic pain symptoms. Pregabalin successfully decreased mechanical and cold hypersensitivity, as a pre-treatment, but was less effective at suppressing cold hypersensitivity when administered as a post-treatment. Furthermore, both i.t. and systemic administration of pregabalin were effective in reducing the behavioral hypersensitivity, with the exception of systemic post-treatment on cold hypersensitivity. We also examined pregabalin's effects at inhibiting hind paw formalin-induced nociception in naïve rats and formalin-induced release of excitatory amino acids in the spinal cord dorsal horn (SCDH) both in naïve rats and in rats with neuropathic pain. Pregabalin dose-dependently reduced nociceptive scores in the formalin test. We also present the first evidence that pregabalin reduces the formalin-induced release of glutamate in SCDH. Furthermore, i.t. pregabalin reduces the enhanced noxious stimulus-induced spinal release of glutamate seen in neuropathic rats. These data suggest that pregabalin reduces neuropathic pain symptoms by inhibiting the release of glutamate in the SCDH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analgesics / pharmacology
  • Analgesics / therapeutic use*
  • Animals
  • Chromatography, High Pressure Liquid / methods
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Drug Administration Routes
  • Drug Administration Schedule
  • Electrochemistry / methods
  • Glutamic Acid / metabolism*
  • Hyperalgesia / drug therapy
  • Hyperalgesia / etiology
  • Male
  • Microdialysis / methods
  • Pain Measurement / methods
  • Pain Threshold / drug effects
  • Physical Stimulation / adverse effects
  • Pregabalin
  • Rats
  • Rats, Long-Evans
  • Sciatica / drug therapy*
  • Sciatica / pathology*
  • Spinal Cord / drug effects
  • Spinal Cord / metabolism*
  • Spinal Cord Injuries / complications
  • Statistics, Nonparametric
  • Time Factors
  • gamma-Aminobutyric Acid / analogs & derivatives*
  • gamma-Aminobutyric Acid / pharmacology
  • gamma-Aminobutyric Acid / therapeutic use

Substances

  • Analgesics
  • Glutamic Acid
  • Pregabalin
  • gamma-Aminobutyric Acid