Potential biosynthetic connections between the two cannabimimetic eicosanoids, anandamide and 2-arachidonoyl-glycerol, in mouse neuroblastoma cells

Abstract

Anandamide (arachidonoyl-ethanolamide, AnNH) and 2-arachidonoyl-glycerol (2-AG) have been suggested to act as endogenous agonists at the brain cannabinoid receptor, and their biosynthetic and degradative mechanisms in nervous tissues and cells have also been partially elucidated. Here we present evidence for the presence, in mouse N18TG2 neuroblastoma cells, of enzymatic activities potentially responsible for the biosynthesis of AnNH and 2-AG from a common phospholipid precursor. Cell homogenates were shown to catalyze: (a) the transfer of an arachidonoyl moiety from the sn-1 position of sn-1,2-di-arachidonoyl-phosphatidylcholine (AAPC) to phosphatidyl-ethanolamine (PE) to form N-arachidonoyl-PE (N-ArPE) and sn-1-lyso-2-arachidonoyl-PC (lyso-APC), (b) the hydrolysis of N-AtPE to AnNH, (c) the hydrolysis of lyso-APC to 2-AG, (d) the hydrolysis of AAPC to sn-1,2-di-arachidonoyl-glycerol (AAG), and (e) the hydrolysis of AAG to 2-AG. From these findings it is possible to suggest that AAPC may serve as precursor for both AnNH and 2-AG biosynthesis through three different pathways.