Schedule-induced drinking and thirst: a pharmacological analysis.

Similar levels of water consumption were induced in two groups of rats by means either of prior fluid deprivation or a schedule of food pellet delivery. Injections of d-amphetamine (0.25, 0.5, 1.0 and 2.0 mg/kg) had similar attenuating effects of drinking induced by both procedures. Chlordiazepoxide (2.5, 5.0, 10 and 20 mg/kg), however, exerted differential actions on schedule-induced and deprivation-induced drinking. Drinking induced by deprivation was facilitated by all doses of this drug while the higher doses decreased levels of schedule-induced drinking. This result emphasises the difficulties involved in using the concept of thirst in explanations of behavior and of drug action.