Antinociceptive effect of (-)-epicatechin in inflammatory and neuropathic pain in rats

Behav Pharmacol. 2018 Apr;29(2 and 3-Spec Issue):270-279. doi: 10.1097/FBP.0000000000000320.

Abstract

The aim of this study was to investigate the antinociceptive potential of (-)-epicatechin and the possible mechanisms of action involved in its antinociceptive effect. The carrageenan and formalin tests were used as inflammatory pain models. A plethysmometer was used to measure inflammation and L5/L6 spinal nerve ligation as a neuropathic pain model. Oral (-)-epicatechin reduced carrageenan-induced inflammation and nociception by about 59 and 73%, respectively, and reduced formalin- induced and nerve injury-induced nociception by about 86 and 43%, respectively. (-)-Epicatechin-induced antinociception in the formalin test was prevented by the intraperitoneal administration of antagonists: methiothepin (5-HT1/5 receptor), WAY-100635 (5-HT1A receptor), SB-224289 (5-HT1B receptor), BRL-15572 (5-HT1D receptor), SB-699551 (5-HT5A receptor), naloxone (opioid receptor), CTAP (μ opioid receptor), nor-binaltorphimine (κ opioid receptor), and 7-benzylidenenaltrexone (δ1 opioid receptor). The effect of (-)-epicatechin was also prevented by the intraperitoneal administration of L-NAME [nitric oxide (NO) synthase inhibitor], 7-nitroindazole (neuronal NO synthase inhibitor), ODQ (guanylyl cyclase inhibitor), glibenclamide (ATP-sensitive K channel blocker), 4-aminopyridine (voltage-dependent K channel blocker), and iberiotoxin (large-conductance Ca-activated K channel blocker), but not by amiloride (acid sensing ion channel blocker). The data suggest that (-)-epicatechin exerts its antinociceptive effects by activation of the NO-cyclic GMP-K channels pathway, 5-HT1A/1B/1D/5A serotonergic receptors, and μ/κ/δ opioid receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analgesics / pharmacology
  • Animals
  • Carrageenan / pharmacology
  • Catechin / metabolism
  • Catechin / pharmacology*
  • Cyclic GMP / metabolism
  • Female
  • Hyperalgesia / drug therapy*
  • Naloxone / pharmacology
  • Neuralgia / drug therapy*
  • Nociception / drug effects
  • Pain / drug therapy
  • Pain Management / methods
  • Pain Measurement
  • Pain Perception / drug effects
  • Rats
  • Rats, Wistar
  • Receptors, Opioid / drug effects
  • Receptors, Serotonin / drug effects
  • Spinal Nerves

Substances

  • Analgesics
  • Receptors, Opioid
  • Receptors, Serotonin
  • Naloxone
  • Catechin
  • Carrageenan
  • Cyclic GMP