自从发现中枢神经系统确有阿片受体以来,神经生理学家确信体内一定有内源性吗啡样物质——阿片受体的配基存在。1974年Terenius等及Hughes果然从哺乳动物脑内发现内源性吗啡样多肽物质,Hughes并命名他所分离的多肽为脑啡肽(Enkephalin)。1975年Hughes等证明它是两个结构十分相似的五肽——甲硫(氨酸)-脑啡肽和亮(氨酸)-脑啡肽的混合物,其 Neurophysiologists have convinced themselves that there must have been an endogenous morphine-like ligand for the opioid receptor in the body, since it has been found to have opioid receptors in the central nervous system. In 1974, Terenius et al. And Hughes found the endogenous morphine-like substance in the brain of mammals. Hughes named the isolated peptide Enkephalin. In 1975, Hughes et al. Demonstrated that it is a mixture of two structurally very similar pentapeptides, methionine (enoate) -enkephalin and enkephalin,