Though narcotic analgesics, and their pharmacological antagonists, are widely used for medical and illicit purposes, comparatively little is known about the effects of these drugs on various complex acquired behaviors. Further, we know very little about how the effects of these drugs may interact with the effects of other drugs that are in common use. This project is attempting to fully characterize the behavioral effects of these drugs in experimental animals, and is attempting to specify significant interactions between the behavioral effects of narcotics and narcotic antagonists and the effects of representative stimulants (e.g., amphetamine), major and minor tranquilizers (e.g., chlorpromazine, chlordiazepoxide) sedative hypnotics (e.g., barbiturates), and antidepressants (e.g., imipramine). The experiments focus on schedule-controlled behaviors maintaaned by food or water delivery, behaviors maintained by postponement or termination of aversive events (avoidance/escape), behaviors suppressed by aversive events (punishment), and behaviors maintained, seemingly anomolously, by presentation of aversive events. We are studying the effects of acutely administered narcotics and narcotic antagonists on a variety of acquired behaviors, and the development of tolerance to the behavioral effects of these drugs with particular reference to differences in tolerance development that may depend on the types of behavior studied. Interactions with other drugs will be studied when either or both drugs are given acutely or chronically.