2-Arachidonoyl-glycerol as an "endocannabinoid": limelight for a formerly neglected metabolite.

Previously believed to simply be an intermediate in tri- and diglyceride metabolism or an alternative precursor for arachidonic acid, 2-arachidonoyl-glycerol has lately attracted renewed interest from lipid biochemists and pharmacologists. This is due to the finding of its cannabimimetic activity. In the present article recent landmarks that have led to the proposition of a role of this monoglyceride as an "endocannabinoid", starting from its newly discovered pharmacological properties in both central and peripheral tissues and ending with studies on the possible biosynthetic pathways for its formation, are reviewed. Also considered are possible interactions with another arachidonic acid-derived endogenous cannabinoid, anandamide.