Abstract: Objective: To compare the sedative and hypnotic effects of ethanol extract of Acanthopanax senticosus root bark (SENR) and ethanol extract of Acanthopanax sessiliflorus root bark (SESR) and their mechanisms, and to explore the feasibility of replacing Acanthopanax senticosus root bark with Acanthopanax sessiliflorus root bark. Methods: According to the different detection indexes, every 120 of 360 male Kunming mice were randomly divided into blank control group, diazepam group (administrated with 3 mg·kg^-1 DZP by gavage), different doses (4, 8, 16, 32 and 64 mg·kg^-1) of SENR groups and different doses (4, 8, 16, 32 and 64 mg·kg^-1) of SESR groups;there were 10 mice in each group. The mice were administrated for 5 d continuously, and the number of locomotor activities of the mice in various groups were recorded. The sub-hypnotic dose (28 mg·kg^-1) of pentobarbital sodium-induced sleep experiment was used to record the incidence of sleep of the mice, and the hypnotic dose (48 mg·kg^-1) of pentobarbital sodium-induced sleep experiment was used to record the sleep latencies and sleep time of the mice. The hypnotic doses and sub-hypnotic doses of SENR and SESR were screened out according to the above experimental results. According to the different model drugs[5-hydroxytryptophan (5-HTP) and flumazenil (FLU)], every 60 of 180 male Kunming mice were randomly divided into blank control group, model control group, SENR group, SESR group, SENR + model drug group and SESR + model drug group;there were 10 mice in each group. The mice were administrated for 5 d continuously, and pentobarbital sodium-induced sleep experiment was used to record the incidence of sleep latencies and sleep time of the mice in various groups, and the 5-hydroxytryptamine (5-HT) and gamma-aminobutyric acid (GABA) levels in brain tissue of the mice were detected by ELISA. Results: Compared with blank control group, the number of locomotor activities of the mice in DZP group, different doses (8, 16, 32 and 64 mg·kg^-1) of SENR and different doses(8,16,32 and 64 mg·kg^-1) of SESR groups was decreased(P<0.05 or P<0.01), the incidence of sleep was increased, the sleep latencies were shortened and the sleep time was prolonged (P<0.05 or P<0.01). Based on the experimental results, the sub-hypnotic doses of SENR and SESR were selected to be 4 mg·kg^-1 and the hypnotic doses were 32 mg·kg^-1. In the 5-HTP model test, compared with blank control group and SENR (4 mg·kg^-1) group and SESR (4 mg·kg^-1) group, the incidences of sleep of the mice in SENR + 5-HTP group and co-administered SESR + 5-HTP group were increased, the sleep latencies were shortened(P<0.01), the sleep time was prolonged(P<0.01), and the levels of 5-HT in the brain tissue were increased (P<0.01). In the FLU model test, compared with blank control group, the sleep latencies of the mice in SENR (32 mg·kg^-1) group and SESR (32 mg·kg^-1) group were shortened(P<0.01) and the sleep time was prolonged (P<0.01). Compared with SENR (32 mg·kg^-1) group and SESR (32 mg·kg^-1) group, the sleep latencies of mice in SENR + FLU group and SESR + FLU group were prolonged(P <0.01), the sleep time was shortened(P <0.01), and the GABA levels in the brain tissue were decreased (P <0.05). Conclusion: Both of SENR and SESR can exhibit the sedative and hypnotic effects in the mice, and their mechanisms may be related to up-regulating the levels of 5-HT and GABA in the brain tissue; in terms of sedative and hypnotic effects, Acanthopanax sessiliflorus root bark could be used as a substitute for Acanthopanax senticosus root bark.

Key words: Acanthopanax senticosus, Acanthopanax sessiliflorus, root bark, sedation, hypnosis, ethanol extract