Figure 4.

Mean (±SEM) active lever (upward bars) and inactive lever (downward bars) responses on the final day of methamphetamine self-administration, 1^st day of extinction, 12^th day of extinction and the methamphetamine-cue-induced reinstatement test session. Open bars represent the group receiving vehicle pretreatment 30 min prior to the 2 hr test session in which each response on the active-lever produced the 6 s light+tone stimulus complex, which had previously accompanied each methamphetamine injection during self-administration training. Gray bars represent the group receiving 1 mg/kg i.p. buspirone pretreatment. Black bars represent the group receiving 3 mg/kg i.p. buspirone pretreatment. * indicates significant reductions in responding on the reinstatement test session (p<0.05) relative to the vehicle control group. n=12/group.