Cannabinoids are compounds found in cannabis. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (Delta9-THC or Delta8-THC), the primary psychoactive compound in cannabis. Cannabidiol (CBD) is another major constituent of the plant. There are at least 144 different cannabinoids isolated from cannabis, exhibiting varied effects.
Synthetic cannabinoids are manufactured artificially. They encompass a variety of distinct chemical classes: the classical cannabinoids structurally related to THC, the nonclassical cannabinoids (cannabimimetics) including the aminoalkylindoles, 1,5-diarylpyrazoles, quinolines, and arylsulfonamides as well as eicosanoids related to endocannabinoids
Medical uses include the treatment of nausea due to chemotherapy, spasticity, and possibly neuropathic pain. Common side effects include dizziness, sedation, confusion, dissociation and “feeling high”.
Before the 1980s, it was often speculated that cannabinoids produced their physiological and behavioral effects via nonspecific interaction with cell membranes, instead of interacting with specific membrane-bound receptors. The discovery of the first cannabinoid receptors in the 1980s helped to resolve this debate. These receptors are common in animals, and have been found in mammals, birds, fish, and reptiles. At present, there are two known types of cannabinoid receptors, termed CB1 and CB2, with mounting evidence of more. The human brain has more cannabinoid receptors than any other G protein-coupled receptor (GPCR) type.
Cannabinoid receptor type 1
CB1 receptors are found primarily in the brain, more specifically in the basal ganglia and in the limbic system, including the hippocampus  and the striatum. They are also found in the cerebellum and in both male and female reproductive systems. CB1 receptors are absent in the medulla oblongata, the part of the brain stem responsible for respiratory and cardiovascular functions. CB1 is also found in the human anterior eye and retina.
Cannabinoid receptor type 2
CB2 receptors are predominantly found in the immune system, or immune-derived cells with varying expression patterns. While found only in the peripheral nervous system, a report does indicate that CB2 is expressed by a subpopulation of microglia in the human cerebellum. CB2 receptors appear to be responsible for immunomodulatory and possibly other therapeutic effects of cannabinoid as seen in vitro and in animal models. Read More…