Fig. 2. Effects of RP extract on SPS-CF stress-induced increased fear memory. (A) Conditioned fear response to context exposure (n=6 for VeN, RPN, VeS, n=7 for RPS). Two-way ANOVA demonstrated a significant effect of SPS-CF (F1,21=2779.0, p<0.001) and RP (F1,21=6.2, p=0.022) on the freezing time. Also a significant SPS-CF × RP (F1,21=5.8, p=0.026) existed. RP reduced freezing in SPS-CF mice (VeS vs RPS: p=0.003, Tukey's HSD post-hoc test). (B) Concentration-dependent effects of RP on contextual freezing (n=41). Univariate ANOVA showed a significant effect of RP doses (F4,36=5.5, p<0.001); Tukey's HSD post-hoc test confirmed that the intensity of freezing in 0.1 mg/kg (p=0.004), 1 mg/kg (p=0.011), 10 mg/kg (p<0.001) and 100 mg/kg (p=0.002) dosed mice was reduced. *p<0.05, **p<0.01, ***p<0.001 vs RPS0. (C) Conditioned fear response to the presentation of auditory cue (n=24). Three-way ANOVA demonstrated a significant effect of SPS-CF (F1,40=52.3, p<0.001), and the presence of auditory cue (F1,40=228.4, p<0.001), but RP administration had no effect (F1,40=0.16, p=0.69). Interaction between SPS-CF × auditory cue was significant (F1,40=32.5, p<0.001). (D) Concentration-dependent effects of RP on cue-induced freezing (n=41). The intensity of freezing was not changed by any of the RP doses in SPS-CF mice (ANOVA; F4,36=0.68, p=0.61). All data represent mean±SEM. VeN, vehicle fed, non-stressed; RPN, RP 0.1 mg/kg fed, non-stressed; VeS, vehicle fed, SPS-CF exposed; RPS, RP 0.1 mg/kg fed, SPS-CF exposed; RPS0, vehicle fed, SPS-CF exposed; RPS0.1, RP 0.1 mg/kg fed, SPS-CF exposed; RPS1, RP 1 mg/kg fed, SPS-CF exposed; RPS10, RP 10 mg/kg fed, SPS-CF exposed; RPS100, RP 100 mg/kg fed, SPS-CF exposed.
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