Antinociceptive effect of methyleugenol on formalin-induced hyperalgesia in mice

Eur J Pharmacol. 2006 Dec 28;553(1-3):99-103. doi: 10.1016/j.ejphar.2006.09.020. Epub 2006 Sep 23.

Abstract

The effects of methyleugenol, an essential oil isolated from Asiasari radix, on antinociception were examined using the formalin test in mice. Oral administration of 10 mg/kg methyleugenol significantly decreased the duration of licking and biting behavior in the second phase without affecting that of the first phase, as did diclofenac, a non-steroidal anti-inflammatory drug. Methyleugenol also inhibited pain-related behaviors induced by intrathecal injection of N-methyl-d-aspartic acid (NMDA), while diclofenac did not affect these behaviors. These effects of methyleugenol were suppressed by bicuculline, a gamma-aminobutyric acid(A) (GABA(A)) antagonist. Muscimol, a GABA(A) agonist, displays the same action as methyleugenol with respect to the formalin test and NMDA-induced behaviors. Methyleugenol did not affect cyclooxygenase-1 and -2 activities. These results suggest that the antinociceptive effect of methyleugenol on the second phase of formalin-induced pain may be due to the inhibition of NMDA receptor-mediated hyperalgesia via GABA(A) receptors.

MeSH terms

  • Anesthetics / therapeutic use*
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
  • Behavior, Animal / drug effects
  • Cyclooxygenase 1 / metabolism
  • Cyclooxygenase 2 / metabolism
  • Diclofenac / therapeutic use
  • Eugenol / analogs & derivatives*
  • Eugenol / therapeutic use
  • Excitatory Amino Acid Agonists / pharmacology
  • Formaldehyde*
  • GABA Agonists / pharmacology
  • Hyperalgesia / chemically induced*
  • Hyperalgesia / drug therapy*
  • Male
  • Mice
  • Muscimol / pharmacology
  • N-Methylaspartate / pharmacology
  • Nociceptors / drug effects

Substances

  • Anesthetics
  • Anti-Inflammatory Agents, Non-Steroidal
  • Excitatory Amino Acid Agonists
  • GABA Agonists
  • Diclofenac
  • Formaldehyde
  • Muscimol
  • methyleugenol
  • Eugenol
  • N-Methylaspartate
  • Cyclooxygenase 1
  • Cyclooxygenase 2