Figure 2.

Mean ± SEM (A & C) active and (B & D) inactive lever presses for amphetamine 0.03 mg/kg/infusion, i.v. (upper panels) and 0.05 mg/kg/infusion, i.v. (lower panels) between EC, IC, and SC rats following Trichostatin A (TsA; 0.3 mg/kg, i.v.) or Vehicle (10% DMSO in saline) pretreatment. These data reflect the average active lever presses of all three of the 0.03 and 0.05 mg/kg/infusion amphetamine sessions. EC rats exhibited significantly fewer active lever responses for amphetamine at 0.03 mg/kg/infusion than IC rats (*=p < .05), but there were no significant differences between EC, IC and SC rats at the 0.05 mg/kg/infusion dose. There were no significant differences between any of the drug pretreatment conditions and there were no significant differences in inactive lever responding between EC, IC, or SC rats in any treatment condition or at any dose.

Abbreviations: DMSO, dimethyl sulfoxide; EC, enriched condition; IC, isolated condition; SC, standard condition; TsA, Trichostatin A