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 CA2+-INDEPENDENT MECHANISMS()

The molecular species compositions of monoacylglycerols obtained from various rat tissues mere examined by reverse-phase high-performance li quid chromatography (HPLC) and gas chromatography-mass spectrometry (G C-MS) analyses. We confirmed that 2-arachidonoylglycerol, an endogenou s cannabinoid receptor agonist, is one of the most abundant molecular species of monoacylglycerols in the brain. Substantial amounts of 2-ar achidonoylglycerol were also found in the liver, spleen, lung and kidn ey, 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+, Important ly, the generation of 2-arachidonoylglycerol was markedly augmented in the presence of Ca2+, suggesting that Ca2+ plays a key role in regula tion of the generation of 2-arachidonoylglycerol in this tissue, (C) 1 998 Federation of European Biochemical Societies.