2-Arachidonoyl glycerol (2-AG) is an endogenous agonist of the cannabinoid (CB) receptors CB1 and CB2 (Kis = 25.3-472 and 145-1,400 nM, respectively).[1],[2],[3] Unlike arachidonoyl ethanolamide, 2-AG is present at relatively high levels in the central nervous system and is the most abundant molecular species of monoacylglycerol (MAG) found in rat brain.[1],[4] Formation of 2-AG is calcium-dependent and is mediated by the activities of phospholipase C (PLC) and diacylglycerol (DAG) lipase.1 2-AG acts as a full agonist at the CB1 receptor. At a concentration of 0.3 nM, 2-AG induces a rapid, transient increase in intracellular free calcium in NG108-15 neuroblastoma X glioma cells through a CB1 receptor-dependent mechanism.2 2-AG is metabolized in vitro by MAG lipase and fatty acid amide hydrolase (FAAH), with MAG lipase likely being the principle metabolizing enzyme in vivo.[5]

Reference:
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[2]. Sugiura, T., Kodaka, T., Nakane, S., et al. Evidence that the cannabinoid CB1 receptor is a 2-arachidonoylglycerol receptor. Structure-activity relationship of 2-arachidonoylglycerol, ether-linked analogues, and related compounds. J. Biol. Chem. 274(5), 2794-2801 (1999).
[3]. Pertwee, R.G. Pharmacology of cannabinoid receptor ligands. Curr. Med. Chem. 6(8), 635-664 (1999).
[4]. Kondo, S., Kondo, H., Nakane, S., et al. 2-Arachidonoylglycerol, an endogenous cannabinoid receptor agonist: Identification as one of the major species of monoacylglycerols in various rat tissues, and evidence for its generation through Ca2+-dependent and -independent mechanisms. FEBS Letters 429(2), 152-156 (1998).
[5]. Dinh, T.P., Carpenter, D., Leslie, F.M., et al. Brain monoglyceride lipase participating in endocannabinoid inactivation. Proceedings of the National Academy of Sciences of the United States of America 99(16), 10819-10824 (2002).