Schematic representation of the anabolic and catabolic pathways so far proposed for the acylethanolamides and 2-AG. Adapted from Di Marzo and Petrosino (2007). Abbreviations used: Abh4, alpha/beta-hydrolase 4; 2-AG, 2-arachidonoylglycerol; DAGL, sn-1-selective diacylglycerol lipase; AMT, putative endocannabinoid membrane transporter; FAAH, fatty acid amide hydrolase; lyso-PLD, lysophospholipase D; MAGLs, monoacylglycerol lipases; NAPE-PLD, N-acylphosphatidyl-ethanolamine-selective phospholipase D; PLA2, phospholipase A2; PLC, phospholipase C; PTPN22, protein tyrosine phosphatase N22.