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Cannabinoid agonist, CP 55,940, prevents capsaicin-induced sensitization of spinal cord dorsal horn neurons.
J Neurophysiol. 2005 Feb; 93(2):989-97.JN

Abstract

Low doses of cannabinoids applied intrathecally attenuate capsaicin-evoked heat and mechanical hyperalgesia via CB1 receptors. Although cannabinoids produce antinociception, in part, by attenuating responses of nociceptive neurons in the spinal cord, few studies have examined the effect of cannabinoids on sensitization of spinal neurons. We therefore investigated whether a cannabinoid receptor agonist, CP 55,940, attenuated excitation and sensitization of spinal nociceptive neurons produced by intraplantar injection of 0.1% capsaicin (10 microl). In rats, wide-dynamic-range (WDR) and high-threshold (HT) neurons were classified according to responses evoked by mechanical stimuli of varying intensity. CP 55,940 (10 microg in 50 microl) or vehicle was applied directly to the spinal cord and responses to mechanical (von Frey monofilament) and heat stimuli were recorded 10 min after drug treatment. CP 55,940 alone did not alter responses to mechanical stimuli; however the enhanced responses to mechanical stimuli after injection of capsaicin into the receptive field were dose dependently attenuated in both HT and WDR neurons. Vehicle-treated neurons increased their response to 300.6 +/- 52.1% of baseline after capsaicin, whereas CP 55,940-treated neurons responded at 153.0 +/- 27.1% of baseline. The effects of CP 55,940 on sensitization to heat were less pronounced; however, CP 55,940 attenuated the capsaicin-evoked decrease in heat threshold in HT neurons. The attenuation by CP 55,940 of sensitization to mechanical stimuli was blocked by pretreatment of the spinal cord with the CB1 receptor antagonist, SR141716A. These studies demonstrate that cannabinoid application to the spinal cord prevents central sensitization.

Authors+Show Affiliations

Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15385593

Citation

Johanek, Lisa M., and Donald A. Simone. "Cannabinoid Agonist, CP 55,940, Prevents Capsaicin-induced Sensitization of Spinal Cord Dorsal Horn Neurons." Journal of Neurophysiology, vol. 93, no. 2, 2005, pp. 989-97.
Johanek LM, Simone DA. Cannabinoid agonist, CP 55,940, prevents capsaicin-induced sensitization of spinal cord dorsal horn neurons. J Neurophysiol. 2005;93(2):989-97.
Johanek, L. M., & Simone, D. A. (2005). Cannabinoid agonist, CP 55,940, prevents capsaicin-induced sensitization of spinal cord dorsal horn neurons. Journal of Neurophysiology, 93(2), 989-97.
Johanek LM, Simone DA. Cannabinoid Agonist, CP 55,940, Prevents Capsaicin-induced Sensitization of Spinal Cord Dorsal Horn Neurons. J Neurophysiol. 2005;93(2):989-97. PubMed PMID: 15385593.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cannabinoid agonist, CP 55,940, prevents capsaicin-induced sensitization of spinal cord dorsal horn neurons. AU - Johanek,Lisa M, AU - Simone,Donald A, Y1 - 2004/09/22/ PY - 2004/9/24/pubmed PY - 2005/3/11/medline PY - 2004/9/24/entrez SP - 989 EP - 97 JF - Journal of neurophysiology JO - J Neurophysiol VL - 93 IS - 2 N2 - Low doses of cannabinoids applied intrathecally attenuate capsaicin-evoked heat and mechanical hyperalgesia via CB1 receptors. Although cannabinoids produce antinociception, in part, by attenuating responses of nociceptive neurons in the spinal cord, few studies have examined the effect of cannabinoids on sensitization of spinal neurons. We therefore investigated whether a cannabinoid receptor agonist, CP 55,940, attenuated excitation and sensitization of spinal nociceptive neurons produced by intraplantar injection of 0.1% capsaicin (10 microl). In rats, wide-dynamic-range (WDR) and high-threshold (HT) neurons were classified according to responses evoked by mechanical stimuli of varying intensity. CP 55,940 (10 microg in 50 microl) or vehicle was applied directly to the spinal cord and responses to mechanical (von Frey monofilament) and heat stimuli were recorded 10 min after drug treatment. CP 55,940 alone did not alter responses to mechanical stimuli; however the enhanced responses to mechanical stimuli after injection of capsaicin into the receptive field were dose dependently attenuated in both HT and WDR neurons. Vehicle-treated neurons increased their response to 300.6 +/- 52.1% of baseline after capsaicin, whereas CP 55,940-treated neurons responded at 153.0 +/- 27.1% of baseline. The effects of CP 55,940 on sensitization to heat were less pronounced; however, CP 55,940 attenuated the capsaicin-evoked decrease in heat threshold in HT neurons. The attenuation by CP 55,940 of sensitization to mechanical stimuli was blocked by pretreatment of the spinal cord with the CB1 receptor antagonist, SR141716A. These studies demonstrate that cannabinoid application to the spinal cord prevents central sensitization. SN - 0022-3077 UR - https://www.unboundmedicine.com/medline/citation/15385593/Cannabinoid_agonist_CP_55940_prevents_capsaicin_induced_sensitization_of_spinal_cord_dorsal_horn_neurons_ L2 - https://journals.physiology.org/doi/10.1152/jn.00673.2004?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -