US scientists have demonstrated the existence of undiscovered chemical pathways to an important class of bioactive lipids in the nervous system. Endocannabinoids are lipid messengers that play a key role in both central and peripheral tissues, where they participate in diverse physiological processes including appetite, pain-sensation, mood, and memory. Unlike other neurotransmitters such as amino acids and neuropeptides, they are not water soluble so cannot be stored in the body and are made on-demand from phospholipid precursors involving complex multiple pathways. A complete understanding of these mechanisms is crucial to understanding their effects in mammalian physiology, explains Benjamin Cravatt and Gabriel Simon at...