Reinforcing properties of perphenazine, haloperidol and amitryptiline in rhesus monkeys

Possible negative reinforcing effects of perphenazine, haloperidol and amitryptiline were studied in rhesus monkeys previously trained to avoid electric shock by responding. Responding extinguished a light associated with an intravenous drug infusion scheduled to occur 30 seconds after the light was switched on. A response occurring when the light was on switched the light off for a period of 1 minute (time-out period). a response during the infusion terminated the infusion. Under these conditions, the monkeys tolerated a large number of saline infusions. Saline was replaced by different doses of perphenazine, haloperidol and amitryptiline, each for 12 successive daily 2-hour sessions. Infusions of perphenazine (0.50-1.6 microng/kg) and to a lesser extent infusions of haloperidol (2.5 microng/kg) generated and maintained responding. Most of the infusions of amitryptiline in the dose range of 1.0 to 10.0 microng/kg were tolerated. Haloperidol and perphenazine in doses higher than 10.0 micmitryptiline (500-3000 microng/kg i.v.) had no influence on shock avoidance behavior. Positive reinforcing effects of these compounds were studied in a group of monkeys trained to respond under a 10 response fixed ratio of intravenous infusions of codeine. None of the three compounds maintained responding previously engendered by codeine.