Effects of chronic ingestion and withdrawal of sodium barbitone on learning in rats.

Rats were submitted to three different manipulations: chronic ingestion of sodium barbitone, which was added to the drinking water; chronic administration of barbitone and subsequent withdrawal of the drug; and drinking water only. Both groups of experimental animals showed deficient acquisition in both shuttle-box avoidance and passive-avoidance response when compared to the control animals. Nevertheless, no impairment was observed in passive avoidance when the period of withdrawal was 15 days. Neither was impairment observed when the animals were tested in a T-maze or in another appetitive task. These results cannot be explained by differences in weight or fluid consumption.