Behavioural and pharmacological dissociation of chlordiazepoxide effects on discrimination and punished responding.
Effects of chlordiazepoxide (CDP) and ethanolamine-O-sulphate (EOS) alone and in combination were tested on the acquisition and performance of continuous reinforcement - time out (CR-TO) and variable interval reinforcement - time out (VI-TO) operant discriminations in rats. CDP disrupted acquisition of CR-TO discrimination; effects were short lived, and neither CR-TO performance nor its reversal were impaired. Acquisition of VI-TO discrimination was increasingly impaired, and performance disrupted in pre-trained animals. EOS alone was inactive, and with CDP exerted only slight interactive effects. When a conflict component was added to the VI-TO schedule, however, EOS showed substantial additive effects with CDP on punished responding. The results suggest that CDP-induced increases in non-rewarded (TO) responding were related to task difficulty, pointing to a discrimination impairment rather than an anxiolytic effect. In addition, the specificity of EOS potentiation may reflect a pharmacological dissociation between CDP effects on discrimination and on punished responding, and suggest that GABA is selectively involved in resistance to punishment.
D000818:Animals; D002707:Chlordiazepoxide / Q000494:pharmacology*; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004983:Ethanolamines / Q000494:pharmacology; D007858:Learning / Q000187:drug effects; D008297:Male; D011678:Punishment; D051381:Rats; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D004983:Ethanolamines; D005680:gamma-Aminobutyric Acid; D002707:Chlordiazepoxide; C020619:ethanolamine O-sulfate