Discontinuation of diazepam and sensitivity to a shock signal: fear conditioning prior to drug treatment.

The present experiment examined the disruptive capacity of a shock CS when Pavlovian training was completed prior to repeated daily treatment with diazepam (DZ). Two groups of rats were given 20 Pavlovian fear conditioning trials (two per day) to establish a light CS as a shock signal. Both groups were then trained for 15 daily sessions to bar press for food reinforcement. Before each session, one group was injected IP with 5 mg/kg DZ and the other with saline. All injections were discontinued after the last training session. Nine days later, the capacity of the CS to disrupt bar pressing was tested. The CS produced greater disruption of bar pressing for rats that had previously received chronic diazepam treatment. The results suggest that DZ discontinuation increases sensitivity to cues established as fear elicitors prior to initial administration of DZ.