Allo reverses increased contextual fear conditioning due to SKF 105,111 treatment. SKF 105,111 was injected 4 h before and Allo 1 h before the conditioning training session. Each value is the mean ± SEM of four animals. *, P < 0.05 in SKF 105,111-treated groups compared with control group or SKF plus Allo-treated group (one-way ANOVA, followed by Bonferroni test).