Cholecystokinin as a stimulus within the conditioned taste aversion baseline of drug discrimination learning

After a determination of the temporal parameters necessary to establish discrimination learning with a 13 ug/kg dose of cholecystokinin (CCK), animals were trained to discriminate a lower dose of CCK (5.6 ug/kg) from distilled water within the conditioned taste aversion baseline of drug discrimination learning. Specifically, rats were injected with CCK prior to the presentation of saccharin-LiCl pairings and with the CCK vehicle prior to the presentation of saccharin alone. After twelve conditioning trials, six of twelve subjects acquired the discrimination, avoiding saccharin following the administration of CCK and consuming the same saccharin solution following the drug vehicle. That a low dose of CCK can be used as a discriminative stimulus within a drug discrimination design may be important in that the procedure can now be used in the assessment of the pharmacological characteristics of CCK at a dose similar to that used in other behavioral assessments of the compound.