The cannabis mode of action

Several plant cannabinoids may interact with the ECS through binding with one or more of the cannabinoid receptors. In some cases, the resulting effects may be therapeutic, while under other conditions unwanted effects may occur. The most well-known effect is caused by THC: consumption of cannabis rich in THC leads to stimulation of central CB1 receptors resulting in the user feeling intoxicated or ‘high’. Besides THC, various other cannabinoids have affinity for CB1 and/or CB2. Some of these act as partial agonists (e.g. CBN, Δ8-THC, CBD) while others show an antagonist effect (e.g. THCV) . Stimulation of the cannabinoid receptors by exogenous plant cannabinoids, or phytocannabinoids, may have an effect on any of the physiological systems normally regulated by the endocannabinoid system, including pain, sleep, appetite, and inflammation.

Cannabis terpenes may influence the therapeutic effect in several possible ways, for example by helping cannabinoids to penetrate the blood brain barrier or by altering liver metabolism of cannabinoids. (McPartland and Russo, 2014). Some terpenes may even compete with cannabinoids at the receptor level. For example, β-caryophyllene is one of the major terpenes found in cannabis, and it selectively binds to the CB2 receptor at nanomolar concentrations, acting as a full agonist (Gertsch 2008). Some terpenes also have their own effects independent of the cannabinoid receptors (Park et al., 2011). Perhaps as a result, some studies show that whole plant preparations of cannabis containing various cannabinoids and terpenes have superior therapeutic effects compared to purified cannabinoids alone. This indicates that, at least for some therapeutic uses, cannabis constituents may work in a synergistic manner.