2-Arachidonoylglycerol (2-AG), is an endocannabinoid, an endogenous agonist of the CB1 receptor. 2-AG, unlike anandamide, is present at relatively high levels in the central nervous system; it is the most abundant molecular species of monoacylglycerol found in mouse and rat brain (~5-10 nmol/g tissue). Detection of 2-AG in brain tissue is complicated by the relative ease of its isomerization to 1-AG during standard lipid extraction conditions. Unlike anandamide, formation of 2-AG is calcium-dependent and is mediated by the activities of phospholipase C (PLC) and diacylglycerol lipase (DAGL). 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-AG is hydrolyzed in vitro by monoacylglycerol lipase (MAGL), fatty acid amide hydrolase (FAAH), and the uncharacterized serine hydrolase enzymes ABHD6 and ABHD12. The exact contribution of each of these enzymes to the termination of 2-AG signaling in vivo is unknown, though it is estimated that MAGL is responsible for ~85% of this activity.