Opiate Receptors and the Neurochemical Correlates of Pain, Volume V, documents the proceedings of the 3rd Congress of the Hungarian Pharmacological Society held in Budapest, 1979. The congress offered a good opportunity to stimulate discussions and exchange of ideas between scientists from various countries who approach the problem of narcotics and pain mechanisms in different ways. The 27 contributions in this volume have enriched knowledge in this rapidly expanding field of pharmacology. This volume begins with a discussion of opiate receptors. The results suggest the interaction of various morphine-like drugs with different opiate receptor populations. The existence in nerve tissue of specific opiate receptors binding morphine and other opioids has led to the assumption of endogenous ligand for opiate receptors. One section of the present volume is devoted to enkephalins and endorphins, their structure-activity relationships, interactions with transmitter and other systems, their behavioral effects, and to factors controlling their release. Some other aspects of nociception; the pathways involved in the mode of action of different types of analgesics, e.g. narcotics and non-narcotics; and their relations to inflammation and active substances, such as prostaglandins and substance P, are discussed from various aspects.