孤啡肽是１９９５年底新发现的一种结构与内阿片肽类似的物质，它的发现引发了国际上相关研究的热潮。近年来的研究已经基本阐明了孤啡肽在中枢及外周的分布及其生化与药理特性，并初步发现该物质参与痛觉调制、影响运动与行为、调控递质释放，还可能参与情绪反应与学习记忆、神经内分泌与免疫过程以及胃的活动等，但其确切作用仍有待于进一步阐明。 Orphanin is a newly discovered substance with similar structure to that of endo-opioid peptide in the end of 1995. Its discovery has triggered the upsurge of related research in the world. In recent years, the research has basically clarified the distribution and the biochemical and pharmacological properties of orphanin in the central and peripheral regions. It has also been found that the substance participates in the modulation of pain, affects the movement and behavior, controls the release of the neurotransmitter, and may also participate in the emotional response and learning Memory, neuroendocrine and immune processes and gastric activity, but its exact role remains to be further elucidated.