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The antinociceptive effects of JWH-015 in chronic inflammatory pain are produced by nitric oxide-cGMP-PKG-KATP pathway activation mediated by opioids.

Negrete R, Hervera A, Leánez S, Martín-Campos JM, Pol O - PLoS ONE (2011)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Grup de Neurofarmacologia Molecular, Institut de Recerca de l'Hospital de la Sta Creu i Sant Pau and Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.

ABSTRACT

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.

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Related in: MedlinePlus

Dorsal root ganglia and paw expression of CB2R.The relative mRNA (A and D) and protein (B and E) expression of CB2R in the ipsilateral side of the dorsal root ganglia (left) and paw (right) from naive and CFA injected WT mice were shown. A representative example of Western blots for CB2R protein (37 kDa) in which β-actin (43 kDa) was used as a loading control is shown in C and F. Data are expressed as mean values ± SEM; n = 4–5 samples per group. * indicates significant differences when compared CFA vs. naïve mice (p<0.03, Student's t test).
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pone-0026688-g003: Dorsal root ganglia and paw expression of CB2R.The relative mRNA (A and D) and protein (B and E) expression of CB2R in the ipsilateral side of the dorsal root ganglia (left) and paw (right) from naive and CFA injected WT mice were shown. A representative example of Western blots for CB2R protein (37 kDa) in which β-actin (43 kDa) was used as a loading control is shown in C and F. Data are expressed as mean values ± SEM; n = 4–5 samples per group. * indicates significant differences when compared CFA vs. naïve mice (p<0.03, Student's t test).

Mentions: The mRNA and protein levels of CB2R in the ipsilateral side of the dorsal root ganglia (A and B) and paw (D and E) from WT mice, with (CFA) and without (naive) inflammatory pain, are shown in Figure 3. While peripheral inflammation did not alter the dorsal root ganglia mRNA and protein expression of CB2R, it significantly increased their expression in the paw (p<0.030 Student's t test as compared to naive animals).


The antinociceptive effects of JWH-015 in chronic inflammatory pain are produced by nitric oxide-cGMP-PKG-KATP pathway activation mediated by opioids.

Negrete R, Hervera A, Leánez S, Martín-Campos JM, Pol O - PLoS ONE (2011)

Dorsal root ganglia and paw expression of CB2R.The relative mRNA (A and D) and protein (B and E) expression of CB2R in the ipsilateral side of the dorsal root ganglia (left) and paw (right) from naive and CFA injected WT mice were shown. A representative example of Western blots for CB2R protein (37 kDa) in which β-actin (43 kDa) was used as a loading control is shown in C and F. Data are expressed as mean values ± SEM; n = 4–5 samples per group. * indicates significant differences when compared CFA vs. naïve mice (p<0.03, Student's t test).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198780&req=5

pone-0026688-g003: Dorsal root ganglia and paw expression of CB2R.The relative mRNA (A and D) and protein (B and E) expression of CB2R in the ipsilateral side of the dorsal root ganglia (left) and paw (right) from naive and CFA injected WT mice were shown. A representative example of Western blots for CB2R protein (37 kDa) in which β-actin (43 kDa) was used as a loading control is shown in C and F. Data are expressed as mean values ± SEM; n = 4–5 samples per group. * indicates significant differences when compared CFA vs. naïve mice (p<0.03, Student's t test).
Mentions: The mRNA and protein levels of CB2R in the ipsilateral side of the dorsal root ganglia (A and B) and paw (D and E) from WT mice, with (CFA) and without (naive) inflammatory pain, are shown in Figure 3. While peripheral inflammation did not alter the dorsal root ganglia mRNA and protein expression of CB2R, it significantly increased their expression in the paw (p<0.030 Student's t test as compared to naive animals).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Grup de Neurofarmacologia Molecular, Institut de Recerca de l'Hospital de la Sta Creu i Sant Pau and Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus