Chapter 4 - Neuroendocrine Correlates of the Endorphins and Enkephalins

Abstract

This chapter discusses the neuroendocrinie correlates of endorphins and enkephalins. “Endogenous opiates” is the name given to naturally occurring substances isolated from brain tissues with pharmacological actions resembling opiate alkaloids. An extensive study of the endogenous opiate peptides has revealed the complexity of their interactions in neurophysiology. From the simple origins of the pentapeptides—Met- and Leuenkephalin and the ß-endorphin-related peptides—it is now apparent that there is a whole range of endogenous opiates. Techniques available for measuring endogenous opiate peptides include the traditional in vitro opiate bioassays, radioreceptor assays, and specific radioimmunoassays. The discovery of endogenous opiate peptides has led to an interest in their possible roles. To investigate this, levels of endogenous opiates have been measured in different physiological and pathological conditions, and observations have been made on the effects of administration of opiate peptides and their analogs and antagonists.