PT  - JOURNAL ARTICLE
AU  - Udoh, Michael
AU  - Santiago, Marina
AU  - Devenish, Steven
AU  - McGregor, Iain S.
AU  - Connor, Mark
TI  - Cannabichromene is a cannabinoid CB2 receptor agonist
AID  - 10.1101/435057
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 435057
4099  - http://biorxiv.org/content/early/2018/11/27/435057.short
4100  - http://biorxiv.org/content/early/2018/11/27/435057.full
AB  - BACKGROUND Cannabichromene (CBC) is one of the most abundant phytocannabinoids in Cannabis spp. It has modest anti-nociceptive and anti-inflammatory effects and potentiates some effects of Δ9-tetrahydrocannabinol (THC) in vivo. How CBC exerts these effects is poorly defined and there is little information about its efficacy at cannabinoid receptors. We sought to determine the functional activity of CBC at CB1 and CB2 receptors.EXPERIMENTAL APPROACH AtT20 cells stably expressing HA-tagged human CB1 and CB2 receptors were used. Assays of cellular membrane potential and loss of cell surface receptors were performed.KEY RESULTS CBC activated CB2 but not CB1 receptors to produce a hyperpolarization of AtT20 cells. Activation of CB2 receptors was antagonised by the CB2 antagonist AM630 and sensitive to pertussis toxin. Co-application of CBC reduced activation of CB2 receptors CP55,940, a potent CB1 and CB2 agonist. Continuous CBC application induced loss of cell surface CB2 receptors and desensitisation of the CB2-induced hyperpolarization.CONCLUSIONS AND IMPLICATIONS Cannabichromene is a selective CB2 receptor agonist displaying higher efficacy than THC in hyperpolarising AtT20 cells. CBC may contribute to the potential therapeutic effectiveness of some cannabis preparations, potentially through CB2-mediated modulation of inflammation.Abbreviations2-AG2-arachidonoyl-glycerol;AEAanandamide;AtT20-CB1Mouse pituitary tumour cells stably transfected with HA human CB1 cells;AtT20-CB2Mouse pituitary tumour cells stably transfected with HA human CB2 cells;CB1Cannabinoid receptor type 1CB2Cannabinoid receptor type 2;CBCcannabichromene;CBDCannabidiol;CBNCannabinol;ECSEndocannabinoid system;GRKG-protein coupled receptor kinase;HAHaemagglutininPTXPertussis toxin;THCTetrahydrocannabinol;THCVTetrahydrocannabivarin.