DISCRIMINATIVE STIMULUS EFFECTS AND ANTIPUNISHMENT EFFECTS OF DRUGS MEASURED DURING THE SAME SESSION

The effects of pentobarbital, diazepam. phencyclidine, buspirone and m ethamphetamine on drug discrimination and on responding under a variab le-interval variable-interval with punishment schedule were studied in pigeons trained to discriminate 5.0 mg/kg pentobarbital from saline. Pentobarbital produced dose-dependent increases in the proportion of r esponses on the drug key and on rates of punished responding. Diazepam had very similar effects except that the dose-effect curve for punish ed responding turned over at the highest dose level Phencyclidine prod uced only partial responding on the drug key and weakly increased puni shed responding. Buspirone produced small increases in punished respon ding, but in the drug discrimination experiments buspirone did not cau se responding on the drug key. Methamphetamine did not produce respond ing on the drug key, nor did it increase rates of punished responding. These experiments are among the first to demonstrate that drug discri mination and other behaviors can be studied within single test session s in the same animals and they suggest that there is a close correspon dence between the discriminative stimulus effects of some drugs and th eir anti-punishment activity.