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The Cannabinoid 1 Receptor Antagonist AM251 Produces Nocifensive Behavior via Activation of ERK Signaling Pathway

Soh Katsuyama, Hirokazu Mizoguchi, Takaaki Komatsu, Kohshi Nagaoka, Shinobu Sakurada, Tsukasa Sakurada

Neuropharmacology. 2010 Nov;59(6):534-41.

PMID: 20654633

Abstract:

Intrathecal (i.t.) injection of AM251, a cannabinoid 1 (CB(1)) receptor antagonist, into the spinal lumbar space of mice elicited a behavioral response consisting of biting and licking with a few scratchings. In this study, we investigated to determine whether i.t. AM251 could influence the activity of extracellular signal-regulated kinase-1 and -2 (ERK1/2), a mitogen-activated protein kinase (MAPK) in neuronal nitric oxide synthase (nNOS) and inducible NOS (iNOS) activation. The CB(1) receptor agonist ACEA, neurokinin 1 (NK(1)) receptor antagonists and NMDA receptor antagonists, inhibited i.t. AM251-induced behavioral response in a dose-dependent manner. The CB(2) receptor agonist, JWH-133 gave no effect on response elicited by i.t. AM251. Both non-selective NOS inhibitors, L-NAME and 7-NI, and N(ω)-propyl-L-arginine, a selective inhibitor of nNOS resulted in a dose-dependent inhibition of i.t. AM251-induced behavioral response. The selective iNOS inhibitor, 1400W, in relatively large doses, inhibited in a non dose-dependent manner. The i.t. injection of AM251 produced a definite activation of ERK1/2 in the lumbar dorsal spinal cord. Behavioral experiments showed that U0126, a MAPK/ERK kinase (MEK) inhibitor, dose-dependently attenuated the behavioral response to i.t. AM251. Spinal activation of ERK1/2 following i.t. AM251 was reduced clearly by N(ω)-propyl-L-arginine and U0126, while 1400W gave a significant effect on only ERK1 activation. These findings suggest that the nNOS-ERK pathway in spinal cord neurones plays an important role in AM251-induced nocifensive behavior and its inhibition may provide significant anti-nociception.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP183232668 AM251 AM251 183232-66-8 Price
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