A water lick conflict paradigm using drug experienced rats.

A modified water-lick conflict paradigm is described, using trained rats for up to 35 weekly test sessions under 48 h of water deprivation. The rats rapidly became maximally suppressed by the punishment. This suppression was attenuated by the anxiolytics lorazepam, diazepam, phenobarbital, and meprobamate. The potentially anxiolytic drug CL 218872 and the anticonvulsant drug valproate sodium were also active. The antiserotonin drugs methysergide, cyproheptadine, cinanserin and parachlorophenylalanine were all inactive, as were several several other distinct classes of psychotropic drugs including propranolol, clonidine, THIP, theophylline, chlorpromazine, paroxetine and ethanol. The paradigm proved reliable, reproducible and useful for large scale investigations. Furthermore, it may provide means for detailed neuropharmacological and anatomical studies.