The influence of haloperidol and amphetamine on two different noise-escape situations in rats

The learning process of two different noise-escape responses—lever pressing and jumping—was studied in the same rats using a shuttle box automatically transformable during the experimental sessions into two Skinner boxes. The effects of different doses of haloperidol and amphetamine were studied in rats overtrained in the two situations.The learning process was slower in the Skinner box than in the shuttle box. To reach the maximum response level in 50% of the rats 13 to 18 training sessions of 5 min were necessary in the shuttle box versus 31 to 36 in the Skinner box.Haloperidol prolonged the latency (T) and reduced the frequency (F and F) of both lever pressing (L) and jumping responses (J) to about the same extent at the same dose levels (lowest effective dose 0.04 mg/kg s.c.). At 0.005 mg/kg haloperidol slightly increased FL.At doses lower than 2.5 mg/kg, amphetamine decreased T in both the Skinner and the shuttle box and the ineffective responses (F) were increased up to 4 to 5 times their control values. The lowest effective dose was 0.16 mg/kg in the shuttle box (FJ) and 0.31 mg/kg in the Skinner box (FL). At 2.5 mg/kg amphetamine increased T and reduced F.