Devane W A, Axelrod J
Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1994 Jul 5;91(14):6698-701. doi: 10.1073/pnas.91.14.6698.
Anandamide, an endogenous eicosanoid derivative (arachidonoylethanolamide), binds to the cannabinoid receptor, a member of the G protein-coupled superfamily. It also inhibits both adenylate cyclase and N-type calcium channel opening. The enzymatic synthesis of anandamide in bovine brain tissue was examined by incubating brain membranes with [14C]ethanolamine and arachidonic acid. Following incubation and extraction into toluene, a radioactive product was identified which had the same Rf value as authentic anandamide in several thin-layer chromatographic systems. When structurally similar fatty acid substrates were compared, arachidonic acid exhibited the lowest EC50 and the highest activity for enzymatic formation of the corresponding ethanolamides. The concentration-response curve of arachidonic acid exhibited a steep slope, and at higher concentrations arachidonate inhibited enzymatic activity. When brain homogenates were separated into subcellular fractions by sucrose density gradient centrifugation, anandamide synthase activity was highest in fractions enriched in synaptic vesicles, myelin, and microsomal and synaptosomal membranes. When several areas of brain were examined, anandamide synthase activity was found to be highest in the hippocampus, followed by the thalamus, cortex, and striatum, and lowest in the cerebellum, pons, and medulla. The ability of brain tissue to enzymatically synthesize anandamide and the existence of specific receptors for this eicosanoid suggest the presence of anandamide-containing (anandaergic) neurons.
花生四烯酸乙醇胺是一种内源性类二十烷酸衍生物（花生四烯酰乙醇胺），它与大麻素受体结合，大麻素受体是G蛋白偶联超家族的一员。它还能抑制腺苷酸环化酶和N型钙通道的开放。通过将脑膜与[14C]乙醇胺和花生四烯酸一起孵育，研究了牛脑组织中花生四烯酸乙醇胺的酶促合成。孵育并萃取到甲苯中后，鉴定出一种放射性产物，在几种薄层色谱系统中其Rf值与纯品花生四烯酸乙醇胺相同。当比较结构相似的脂肪酸底物时，花生四烯酸表现出最低的EC50和最高的酶促形成相应乙醇酰胺的活性。花生四烯酸的浓度-反应曲线斜率陡峭，在较高浓度时花生四烯酸抑制酶活性。当通过蔗糖密度梯度离心将脑匀浆分离成亚细胞组分时，花生四烯酸乙醇胺合酶活性在富含突触小泡、髓磷脂、微粒体和突触体膜的组分中最高。当检查脑的几个区域时，发现花生四烯酸乙醇胺合酶活性在海马体中最高，其次是丘脑、皮质和纹状体，在小脑、脑桥和延髓中最低。脑组织酶促合成花生四烯酸乙醇胺的能力以及这种类二十烷酸的特异性受体的存在表明存在含花生四烯酸乙醇胺（花生四烯酸乙醇胺能）神经元。
