ABSTRACT
The last thirty years has seen a revolution in the understanding of the mechanisms by which pain is processed in the central nervous system. From the discovery of endogenous opiate receptors and characterization of opioid peptides to the delineation of the central nervous system structures and pathways responsible for the processing and modulation of nociceptive signals, a remarkable composite of information has become available. As a result, general conceptions concerning the nature of pain and pain modulation have changed and evolved, often with practical clinical benefits.
