摘要: Opioid receptors have been the focus of vigorous research efforts during past decade. From initial concept a pharmacologic receptor complementary to morphine-like agents, much more complex picture has emerged. A family receptors, collectively known as opioid which interact with opioids, identified. The interest in these stems not only from grounds but also need characterize physiologic importance their endogenous ligands, peptides or endorphins. This latter aspect will be considered present chapter.