Electrophysiological aspects of the properties of potentially addictive drugs

: Considerable progress has been made during the last ten years in the study of the mechanism of action of addictive drugs. In this text, data concerning endogenous opioids and opiates are described. After a brief summary of the physiology of brain opioid systems, the various electrophysiological effects of these substances in the mammalian central nervous system are described. Finally, we summarize some experimental data allowing a better understanding of the development of tolerance and dependence to opiates in the rat.