Phytocannabinoids are plant substances that stimulate cannabinoid receptors. These cannabinoids are abundant in the resin that is produced by glandular structures in the cannabis plant called trichomes. This resin is also rich in terpenes, which are responsible for the characteristic smell of the cannabis plant. Delta-9-tetrahydrocannabinol, or THC, is the most psychoactive and certainly the most known of these substances, but other cannabinoids such as cannabidiol (CBD) and cannabinol (CBN) are gaining the interest due to a variety of healing properties. Cannabinoid receptors are present throughout the body, embedded in cell membranes, and are believed to be more numerous than any other receptor system. When cannabinoid receptors are stimulated, a variety of physiologic processes begin. Researchers have identified two cannabinoid receptors: CB1, predominantly present in the nervous system, connective tissues, glands, and organs, and CB2, predominantly found in the immune system. Many tissues contain both CB1 and CB2 receptors, each linked to a different action.
Endocannabinoids are substances our bodies naturally make to stimulate CB1 and CB2 receptors. The two most well understood of these molecules are anandamide and 2-arachidonoylglycerol (2-AG), they are synthesized on-demand from cell membrane arachidonic acid derivatives, have a local effect and short half-life before being degraded by the enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL).