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Cannabinoids desensitize capsaicin and mustard oil responses in sensory neurons via TRPA1 activation.
J Neurosci. 2008 Jan 30; 28(5):1064-75.JN

Abstract

Although the cannabinoid agonists R-(+)-(2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrol[1,2,3-de]-1,4-benzoxazin-6-yl)-(1-naphthalenyl) methanone mesylate [WIN 55,212-2 (WIN)] and (R,S)-3-(2-iodo-5-nitrobenzoyl)-1-(1-methyl-2-piperidinylmethyl)-1H-indole (AM1241) exert peripheral antihyperalgesia in inflammatory pain models, the mechanism for cannabinoid-induced inhibition of nociceptive sensory neurons has not been fully studied. Because TRPV1 and TRPA1 channels play important roles in controlling hyperalgesia in inflammatory pain models, we investigated their modulation by WIN and AM1241. The applications of WIN (>5 microM) and AM1241 (>30 microM) inhibit responses of sensory neurons to capsaicin and mustard oil. To determine potential mechanisms for the inhibition, we evaluated cannabinoid effects on nociceptors. WIN and AM1241 excite sensory neurons in a concentration-dependent manner via a nonselective Ca2+-permeable channel. The expression of TRP channels in CHO cells demonstrates that both WIN and AM1241 activate TRPA1 and, by doing so, attenuate capsaicin and mustard oil responses. Using TRPA1-specific small interfering RNA or TRPA1-deficient mice, we show that the TRPA1 channel is a sole target through which WIN and mustard oil activate sensory neurons. In contrast, AM1241 activation of sensory neurons is mediated by TRPA1 and an unknown channel. The knockdown of TRPA1 activity in neurons completely eliminates the desensitizing effects of WIN and AM1241 on capsaicin-activated currents. Furthermore, the WIN- or AM1241-induced inhibition of capsaicin-evoked nocifensive behavior via peripheral actions is reversed in TRPA1 null-mutant mice. Together, this study demonstrates that certain cannabinoids exert their peripheral antinocifensive actions via activation of the TRPA1 channel on sensory neurons.

Authors+Show Affiliations

Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA. akopian@uthscsa.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

18234885

Citation

Akopian, Armen N., et al. "Cannabinoids Desensitize Capsaicin and Mustard Oil Responses in Sensory Neurons Via TRPA1 Activation." The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, vol. 28, no. 5, 2008, pp. 1064-75.
Akopian AN, Ruparel NB, Patwardhan A, et al. Cannabinoids desensitize capsaicin and mustard oil responses in sensory neurons via TRPA1 activation. J Neurosci. 2008;28(5):1064-75.
Akopian, A. N., Ruparel, N. B., Patwardhan, A., & Hargreaves, K. M. (2008). Cannabinoids desensitize capsaicin and mustard oil responses in sensory neurons via TRPA1 activation. The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, 28(5), 1064-75. https://doi.org/10.1523/JNEUROSCI.1565-06.2008
Akopian AN, et al. Cannabinoids Desensitize Capsaicin and Mustard Oil Responses in Sensory Neurons Via TRPA1 Activation. J Neurosci. 2008 Jan 30;28(5):1064-75. PubMed PMID: 18234885.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cannabinoids desensitize capsaicin and mustard oil responses in sensory neurons via TRPA1 activation. AU - Akopian,Armen N, AU - Ruparel,Nikita B, AU - Patwardhan,Amol, AU - Hargreaves,Kenneth M, PY - 2008/2/1/pubmed PY - 2008/2/20/medline PY - 2008/2/1/entrez SP - 1064 EP - 75 JF - The Journal of neuroscience : the official journal of the Society for Neuroscience JO - J Neurosci VL - 28 IS - 5 N2 - Although the cannabinoid agonists R-(+)-(2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrol[1,2,3-de]-1,4-benzoxazin-6-yl)-(1-naphthalenyl) methanone mesylate [WIN 55,212-2 (WIN)] and (R,S)-3-(2-iodo-5-nitrobenzoyl)-1-(1-methyl-2-piperidinylmethyl)-1H-indole (AM1241) exert peripheral antihyperalgesia in inflammatory pain models, the mechanism for cannabinoid-induced inhibition of nociceptive sensory neurons has not been fully studied. Because TRPV1 and TRPA1 channels play important roles in controlling hyperalgesia in inflammatory pain models, we investigated their modulation by WIN and AM1241. The applications of WIN (>5 microM) and AM1241 (>30 microM) inhibit responses of sensory neurons to capsaicin and mustard oil. To determine potential mechanisms for the inhibition, we evaluated cannabinoid effects on nociceptors. WIN and AM1241 excite sensory neurons in a concentration-dependent manner via a nonselective Ca2+-permeable channel. The expression of TRP channels in CHO cells demonstrates that both WIN and AM1241 activate TRPA1 and, by doing so, attenuate capsaicin and mustard oil responses. Using TRPA1-specific small interfering RNA or TRPA1-deficient mice, we show that the TRPA1 channel is a sole target through which WIN and mustard oil activate sensory neurons. In contrast, AM1241 activation of sensory neurons is mediated by TRPA1 and an unknown channel. The knockdown of TRPA1 activity in neurons completely eliminates the desensitizing effects of WIN and AM1241 on capsaicin-activated currents. Furthermore, the WIN- or AM1241-induced inhibition of capsaicin-evoked nocifensive behavior via peripheral actions is reversed in TRPA1 null-mutant mice. Together, this study demonstrates that certain cannabinoids exert their peripheral antinocifensive actions via activation of the TRPA1 channel on sensory neurons. SN - 1529-2401 UR - https://www.unboundmedicine.com/medline/citation/18234885/Cannabinoids_desensitize_capsaicin_and_mustard_oil_responses_in_sensory_neurons_via_TRPA1_activation_ L2 - http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=18234885 DB - PRIME DP - Unbound Medicine ER -