title: Evidence for the Participation of ATP-sensitive Potassium Channels in the Antinociceptive Effect of Curcumin.
abstract: BACKGROUND
  It has been reported that curcumin, the main active compound of Curcuma longa, also known as turmeric, exhibits antinociceptive properties. The aim of this study was to examine the participation of ATP-sensitive potassium channels (K(ATP) channels) and, in particular, that of the L-arginine-nitric oxide-cyclic GMP-K(ATP) channel pathway, in the antinociceptive effect of curcumin.
  
  
  METHODS
  Pain was induced by the intraplantar injection of 1% formalin in the right hind paw of Wistar rats. Formalin-induced flinching behavior was interpreted as an expression of nociception. The antinociceptive effect of oral curcumin was explored in the presence and absence of local pretreatment with L-NAME, an inhibitor of nitric oxide synthase, ODQ, an inhibitor of soluble guanylyl cyclase, and glibenclamide, a blocker of K(ATP) channels.
  
  
  RESULTS
  Oral curcumin produced a dose-dependent antinociceptive effect in the 1% formalin test. Curcumin-induced antinociception was not altered by local L-NAME or ODQ, but was significantly impaired by glibenclamide.
  
  
  CONCLUSIONS
  Our results confirm that curcumin is an effective antinociceptive agent. Curcumin-induced antinociception appears to involve the participation of K(ATP) channels at the peripheral level, as local injection of glibenclamide prevented its effect. Activation of K(ATP) channels, however, does not occur by activation of the L-arginine-nitric oxide-cGMP-K(ATP) channel pathway.
authors.affiliation: Department of Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico, DF, Mexico.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: De Paz-Campos
authors.forename: Aracely Evangelina
authors.initials: AE
authors.lastname: Chávez-Piña
authors.forename: Mario I
authors.initials: MI
authors.lastname: Ortiz
authors.forename: Gilberto
authors.initials: G
authors.lastname: Castañeda-Hernández
keywords: Curcuma longa; antinociception; curcumin; potassium channels; turmeric