Previous research has demonstrated that naloxone, an opiate antagonist, facilitates time-dependent memory processes. The present study was undertaken to determine whether the effect of naloxone on memory processes is shared by other opiate antagonists and whether this effect exhibits stereospecificity. The opiate antagonists used included naloxone, naltrexone, deprenorphine, and levallorphan. In addition, stereospecificity was evaluated by the use of dextrallorphan. The results demonstrate that increased retention of passive avoidance conditioning in rats is produced by posttraining administration of each of the opiate antagonists employed in this investigation. In addition, the effect of theopiate antagonist levallorphan was demonstrated to be stereospecific because dextrallorphan did not significantly alter retention. This experiment provides strong support for the interpretation that naloxone facilitates retention of passive avoidance conditioning as a function of its opiate antagonist properties.
ASJC Scopus subject areas