Forty-eight hours later, the H-RI and L-RI rats were tested for heroin-induced reinstatement, and Fig. 2D show individual reinstatement of operant responding induced by heroin priming. ANOVA revealed a significant main effect of Lever [F(1,51) = 4.89, p<0.05]. Newman-Keuls post hoc tests showed that both the H-RI and L-RI rats responded significantly more on the active lever than the inactive lever during the 3-h session following the heroin priming injection (0.25 mg/kg, s.c.) (p<0.05). The NR rats did not show differences between the active and inactive lever responding. Following the heroin injection, both the H-RI and L-RI rats responded significantly more on the active lever than the NR rats (p<0.05), with no differences between the H-RI and L-RI groups (Fig. 2F).
