Cannabinoid receptor

The cannabinoid receptors are a class of cell membrane receptors under the G-protein coupled receptor superfamily.Cannabinoid receptors are activated by ligands, which are lipid compounds known collectively as cannabinoids. Further distinction of these ligands separates endogenous cannabinoids, which are generated naturally inside the body, from exogenous cannabinoids, which are introduced into the body as cannabis or a related synthetic compound. There are currently two known subtypes, termed CB1 and CB2. The CB1 receptor is expressed mainly in the brain , but also in the lungs, liver and kidneys. The CB2 receptor is mainly expressed in the immune system and in hematopoietic cells. Mounting evidence suggests that there are novel cannabinoid receptors that is, non-CB1 and non-CB2, which are expressed in endothelial cells and in the CNS. In 2007, the binding of several cannabinoids to a G protein-coupled receptor in the brain was described.