The Opiate Receptor

Binding of radioactive opiates and opiate antagonists to the opiate receptor in the brain and other tissues can be shown. This binding mediates the pharmacologic effects of the drugs. The regional distribution of the opiate receptor in monkey and human brain parallels the motivational-affective pathways of pain perception and comprises several limbic system structures. In subcellular fractionation experiments, the opiate receptor is localized to synaptic membranes. The influence of sodium on receptor binding permits predictions of the extent to which a drug possesses opiate agonist, antagonist, or mixed properties. The simple, sensitive, and specific opiate receptor binding assay facilitates development of pure opiate antagonists for treating narcotic addiction and mixed agonist-antagonist agents with potential as nonaddicting analgesics.