Water intake and time course of drinking after single or repeated chlordiazepoxide injections.

Chlordiazepoxide (5.0, 10.0 or 15.0 mg/kg) was given to rats either acutely or for 9 consecutive days. Its effects were examined in a 15-min drinking test in which latency to drink, volume of water consumption and the time-course of drinking were measured. Chlordiazepoxide (10.0 mg/kg) produced the strongest stimulant effect on drinking and enhanced the frequency of occurrence of drinking both at the beginning and at the end of the test period. Chlordiazepoxide (15.0 mg/kg) delayed the onset of drinking and its peak effect was observed later than for other injection conditions. Single and repeated administration of chlordiazepoxide had the same effects on the measures taken in the test. Initial sedation to the drug treatment and subsequent tolerance to this effect were not, therefore, factors influencing the drug effects observed in this experiment. Possible mechanisms underlying the stimulation of drinking by chlordiazepoxide are considered.