[Structure-activity relationship of synthetic and semisynthetic opioid agonists and antagonists].

: This account presents the chemical structure-pharmacological activity relationships of semi-synthetic morphine and synthetic morphinan and benzomorphan derivatives. Substitution of nitrogen confers the analgesic or morphine antagonist activity. Opiate receptor selectivity of these compounds is also discussed. The importance of morphine agonists, and antagonists is mentioned with particular reference to the opiate receptor mapping.