EFFECT OF DIPHENYLHYDANTOIN SODIUM AND CHLORDIAZEPOXIDE ALONE AND IN COMBINATION ON PUNISHMENT BEHAVIOR

Punishment behavior was obtained in rats by simultaneously punishing and rewarding all lever presses made during the presentation of a non-aversive tone. When stable control performances were established, animals were given various doses of diphenylhydantoin or chlordiazepoxide. In addition, drug interaction studies were conducted with a non-effective dose of the former and selected doses of chlordiazepoxide. When diphenylhydantoin was given at effective anti-convulsant doses it did not diminish the suppressant effect of response produced shock. When the animals were given chlordiazepoxide after doses as low as 1.875 mg/kg, significant diminution was obtained in certain rats; and effects were dose-dependent until a clearly depressant dose was given. Both agents reduced variable interval responding after a dose of 15 mg/kg. Diphenylhydantoin did not enhance or antagonize the effects of chlordiazepoxide in the punishment phase of the schedule. However, some animals given non-depressant doses of each in combination did show a significant reduction in response rate in the variable interval component of the schedule. © 1969 Springer-Verlag.