The Opiate Receptors

Abstract

The extract of the opium poppy is among the oldest materials used for medicinal purposes, and the study of the major alkaloid in this extract, morphine. is one of the oldest areas of biological research. Our lack of understanding on the molecular level of how morphine and its analogues produce their effects may be in large part related to the fact that they exert most of their actions on the central nervous system. the most complex organ in animals and man. The opiates produce a large variety of pharmacological responses, the most important of which are analgesia. euphoria, and addiction. The latter includes the development of tolerance and physiological and psychological dependence. The discovery of opiate receptors in the central nervous system of animals and man and the resulting discovery of endogenous opiate-like ligands for these receptors (discussed in this issue by L. Terenius and introduced briefly in this review) have given rise to considerable activity and excite­ ment in the field of opiate research. In this review we attempt to cover. within the limitations of space, the most significant advances in our knowledge of opiate receptors since their discovery.