2-arachidonoylglycerol, an endogenous cannabinoid receptor agonist:: identification as one of the major species of monoacylglycerols in various rat tissues, and evidence for its generation through Ca2+-dependent and -independent mechanisms

The molecular species compositions of monoacylglycerols obtained from various rat tissues mere examined by reverse-phase high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analyses. We confirmed that 2-arachidonoylglycerol, an endogenous cannabinoid receptor agonist, is one of the most abundant molecular species of monoacylglycerols in the brain. Substantial amounts of 2-arachidonoylglycerol were also found in the liver, spleen, lung and kidney, but the levels were considerably lo,ver than that in the brain, We found that a small amount of 2-arachidonoylglycerol mas generated in a brain homogenate during incubation in the absence of Ca2+, Importantly, the generation of 2-arachidonoylglycerol was markedly augmented in the presence of Ca2+, suggesting that Ca2+ plays a key role in regulation of the generation of 2-arachidonoylglycerol in this tissue, (C) 1998 Federation of European Biochemical Societies.