A sensitive endocannabinoid assay. The simultaneous analysis of N-acylethanolamines and 2-monoacylglycerols

Mammalian cells produce both N-arachidonoylethanolamine (20:4n-6 NAE, anandamide) and 2-arachidonoylglycerol (2-AG), lipid signaling molecules that activate cannabinoid receptors. Because both agonists occur in the presence of receptor-inactive congeners, we have developed a sensitive method for the simultaneous assay of N-acylethanolamines (NAEs) and 2-monoacylglycerols (2-MAG). These lipid classes are isolated from total lipids by solid phase extraction and converted to tert-butyldimethylsilyl (tBDMS) derivatives in the presence of deuterated analogs. The tBDMS derivatives are analyzed by gas chromatography/mass spectrometry using selected ion monitoring programs specific for NAE and 2-MAG. Individual NAEs and 2-MAGs can be quantified in the nanogram and subnanogram range. The NAE and 2-MAG compositions of rat organs and cultured JB6 cells are reported.