Cannabichromene is a cannabinoid CB2 receptor agonist

BACKGROUNDCannabichromene (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 {Delta}9-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.\n\nEXPERIMENTAL APPROACHAtT20 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.\n\nKEY RESULTSCBC 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.\n\nCONCLUSIONS AND IMPLICATIONSCannabichromene 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.