^ Jump up to: a b c Campos AC, Moreira FA, Gomes FV, Del Bel EA, Guimarães FS (December 2012). "Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences (Review). 367 (1607): 3364–78. doi:10.1098/rstb.2011.0389. PMC 3481531. PMID 23108553.
Cannabidiol has low affinity for the cannabinoid CB1 and CB2 receptors, although it can act as an antagonist of CB1/CB2 agonists despite this low affinity. Cannabidiol may be an antagonist of GPR55, a G protein-coupled receptor and putative cannabinoid receptor that is expressed in the caudate nucleus and putamen in the brain. It also may act as an inverse agonist of GPR3, GPR6, and GPR12. CBD has been shown to act as a serotonin 5-HT1A receptor partial agonist. It is an allosteric modulator of the μ- and δ-opioid receptors as well. The pharmacological effects of CBD may involve PPARγ agonism and intracellular calcium release.
In nature, Cannabis ruderalis typically has the lowest levels of THC, Cannabis sativa has a higher level of THC than it has CBD, and Cannabis indica has a higher level of CBD than it has THC. However, since man has been cultivating cannabis (and especially Cannabis sativa) for thousands of years, the effects of artificial selections have led to several different types of cannabis even within the same species, depending on the purpose the cannabis was cultivated for.
The good news is that numerous states have enacted legislation that allows for the use of CBD. Just four states (Idaho, South Dakota, Nebraska, and Kansas) forbid any access to marijuana. Ten states and Washington, D.C., currently allow for both medical and recreational use of cannabis, including CBD products. The other 36 states allow for the use of medical cannabis in some form, though some of these relegate this to CBD oil only.