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Effect of CP55,940 on mechanosensory spinal neurons following chronic inflammation.
Neurosci Lett. 2007 Mar 06; 414(2):105-9.NL

Abstract

Cannabinoid receptor agonists have previously been shown to produce antinociceptive effects in rodent models of inflammatory pain. In the present study, we characterized responses of spinal dorsal horn neurons receiving sensory input from the hind paw in rats that had received intraplantar injection of complete Freund's adjuvant (CFA), and examined effects of the nonselective CB1/2 receptor agonist CP55,940 on spinal neuron responses. Systemic (i.v.) administration of CP55,940 failed to attenuate responses of dorsal horn neurons to noxious mechanical stimulation in naïve rats, but significantly reduced responses in CFA-inflamed rats to 25.78+/-13.7% of vehicle control at a cumulative dose of 0.8 mg/kg (ID50=0.28+/-0.02 mg/kg). Additionally, local administration of CP55,940 (10 microM) to the spinal cord reduced responses of mechanosensory dorsal horn neurons in CFA-inflamed rats to 67.15+/-7.1% of vehicle control. The inhibitory action of CP55,940 on spinal dorsal horn neurons in CFA-inflamed rats was mediated by CB1 receptors since local pretreatment with the CB1 receptor antagonist AM251 (10 microM) blocked this effect, while the CB2 receptor antagonist AM630 (10 microM) was ineffective. Our results suggest that following inflammation, the inhibition of spinal nociceptive transmission by CP55,940 is mediated in part by spinal CB1 receptors, and not spinal CB2 receptors.

Authors+Show Affiliations

Department of Pain Research, Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486, United States. kar_chan_choong@merck.comNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17194542

Citation

Choong, Kar-Chan, et al. "Effect of CP55,940 On Mechanosensory Spinal Neurons Following Chronic Inflammation." Neuroscience Letters, vol. 414, no. 2, 2007, pp. 105-9.
Choong KC, Su X, Urban MO. Effect of CP55,940 on mechanosensory spinal neurons following chronic inflammation. Neurosci Lett. 2007;414(2):105-9.
Choong, K. C., Su, X., & Urban, M. O. (2007). Effect of CP55,940 on mechanosensory spinal neurons following chronic inflammation. Neuroscience Letters, 414(2), 105-9.
Choong KC, Su X, Urban MO. Effect of CP55,940 On Mechanosensory Spinal Neurons Following Chronic Inflammation. Neurosci Lett. 2007 Mar 6;414(2):105-9. PubMed PMID: 17194542.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of CP55,940 on mechanosensory spinal neurons following chronic inflammation. AU - Choong,Kar-Chan, AU - Su,Xin, AU - Urban,Mark O, Y1 - 2006/12/27/ PY - 2006/09/06/received PY - 2006/10/24/revised PY - 2006/12/06/accepted PY - 2006/12/30/pubmed PY - 2007/5/9/medline PY - 2006/12/30/entrez SP - 105 EP - 9 JF - Neuroscience letters JO - Neurosci Lett VL - 414 IS - 2 N2 - Cannabinoid receptor agonists have previously been shown to produce antinociceptive effects in rodent models of inflammatory pain. In the present study, we characterized responses of spinal dorsal horn neurons receiving sensory input from the hind paw in rats that had received intraplantar injection of complete Freund's adjuvant (CFA), and examined effects of the nonselective CB1/2 receptor agonist CP55,940 on spinal neuron responses. Systemic (i.v.) administration of CP55,940 failed to attenuate responses of dorsal horn neurons to noxious mechanical stimulation in naïve rats, but significantly reduced responses in CFA-inflamed rats to 25.78+/-13.7% of vehicle control at a cumulative dose of 0.8 mg/kg (ID50=0.28+/-0.02 mg/kg). Additionally, local administration of CP55,940 (10 microM) to the spinal cord reduced responses of mechanosensory dorsal horn neurons in CFA-inflamed rats to 67.15+/-7.1% of vehicle control. The inhibitory action of CP55,940 on spinal dorsal horn neurons in CFA-inflamed rats was mediated by CB1 receptors since local pretreatment with the CB1 receptor antagonist AM251 (10 microM) blocked this effect, while the CB2 receptor antagonist AM630 (10 microM) was ineffective. Our results suggest that following inflammation, the inhibition of spinal nociceptive transmission by CP55,940 is mediated in part by spinal CB1 receptors, and not spinal CB2 receptors. SN - 0304-3940 UR - https://www.unboundmedicine.com/medline/citation/17194542/Effect_of_CP55940_on_mechanosensory_spinal_neurons_following_chronic_inflammation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0304-3940(06)01307-3 DB - PRIME DP - Unbound Medicine ER -