ABSTRACT
The basic mechanisms underlying addictive processes are, unfortunately, not as yet well understood. This remains true for the opiates, although spectacular progress has been made over the last half decade in this field, in which two central discoveries have immensely improved our understanding of their acute actions. These are the identification of their specific binding sites (receptors) in the central nervous system, followed, a few years later, by the detection of the endogenous (peptide) ligands of the opiate receptors (see Herz, 1978).
