THE SIGNIFICANCE OF SUBSTITUTIONS AT C-6 OF 4,5-EPOXYMORPHINAN-6-ONESIN ANALGESIC POTENCY AND RELATIONS TO SUBPOPULATIONS OF OPIOID RECEPTORS

The title compounds were elvaluated to assess their analgesic and othe r opiate like properties. All the compounds tested -oxime, -hydrazone, -phenylhydrazone, -semicarbazone, derivatives of dihydromorphinone an d dihydrocodeinone produced naloxone-reversible analgesic action, weak er than the corresponding precursor molecules, but stronger, than morp hine. Their sedative actions declined to a smaller extent, similar to their opiate-like inhibitory action on contractions of electrically st imulated guinea pig ilea. It is concluded, that these compounds might act through opiate mu-receptors, consistently with in vitro receptor b inding studies by Krizsan et al. (1991). However, these compounds fail ed to possess in vivo or in vitro irreversible activity which was also suggested by receptor binding studies.