The Antinociceptive Effects of JWH-015 in Chronic Inflammatory Pain Are Produced by Nitric Oxide-cGMP-PKG-KATP Pathway Activation Mediated by OpioidsReport as inadecuate




The Antinociceptive Effects of JWH-015 in Chronic Inflammatory Pain Are Produced by Nitric Oxide-cGMP-PKG-KATP Pathway Activation Mediated by Opioids - Download this document for free, or read online. Document in PDF available to download.

Background

Cannabinoid 2 receptor CB2R agonists attenuate inflammatory pain but the precise mechanism implicated in these effects is not completely elucidated. We investigated if the peripheral nitric oxide-cGMP-protein kinase G PKG-ATP-sensitive K+ KATP channels signaling pathway triggered by the neuronal nitric oxide synthase NOS1 and modulated by opioids, participates in the local antinociceptive effects produced by a CB2R agonist JWH-015 during chronic inflammatory pain.

Methodology-Principal Findings

In wild type WT and NOS1 knockout NOS1-KO mice, at 10 days after the subplantar administration of complete Freund-s adjuvant CFA, we evaluated the antiallodynic von Frey filaments and antihyperalgesic plantar test effects produced by the subplantar administration of JWH-015 and the reversion of their effects by the local co-administration with CB2R AM630, peripheral opioid receptor naloxone methiodide, NX-ME or CB1R AM251 antagonists. Expression of CB2R and NOS1 as well as the antinociceptive effects produced by a high dose of JWH-015 combined with different doses of selective L-guanylate cyclase ODQ or PKG Rp-8-pCPT-cGMPs inhibitors or a KATP channel blocker glibenclamide, were also assessed. Results show that the local administration of JWH-015 dose-dependently inhibited the mechanical and thermal hypersensitivity induced by CFA which effects were completely reversed by the local co-administration of AM630 or NX-ME, but not AM251. Inflammatory pain increased the paw expression of CB2R and the dorsal root ganglia transcription of NOS1. Moreover, the antinociceptive effects of JWH-015 were absent in NOS1-KO mice and diminished by their co-administration with ODQ, Rp-8-pCPT-cGMPs or glibenclamide.

Conclusions-Significance

These data indicate that the peripheral antinociceptive effects of JWH-015 during chronic inflammatory pain are mainly produced by the local activation of the nitric oxide-cGMP-PKG-KATP signaling pathway, triggered by NOS1 and mediated by endogenous opioids. These findings suggest that the activation of this pathway might be an interesting therapeutic target for the treatment of chronic inflammatory pain with cannabinoids.



Author: Roger Negrete, Arnau Hervera, Sergi Leánez, Jesús M. Martín-Campos, Olga Pol

Source: http://plos.srce.hr/



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