Abstract: Objective: To investigate the antianxiety effect of schisandrin B (SchB) in the ICR mice,and to elucidate its related mechanisms. Methods: The ICR mice were divided into blank control group (administered with distilled water intragastrically), 2.5 mg·kg^-1 SchB group,5 mg·kg^-1 SchB group,and 10·mg·kg^-1 SchB group (administered with SchB intragastrically).After the successive administration for 7 d,cross maze test and zero maze test were conducted in all the mice,and then the peripheral blood and brain tissue samples of the mice in blank control group and 10 mg·kg^-1 SchB group were taken.The levels of γ-aminobutyric acid (GABA) and glutamic acid (Glu) in the peripheral blood and brain tissue of the mice were detected by ELISA,and the ratio of GABA/Glu was calculated.The expression levels of the α1 subunit of the γ-aminobutyric acid (GABAARα1) and the γ2 subunit of the γ-aminobutyric acid (GABAARγ2) in the brain tissue of the mice were detected by Western blotting method. Results: In the elevated plus maze test,the percentages of number of open arm entries in 5.0 and 10.0 mg·kg^-1SchB groups were significantly increased compared with blank control group(P<0.05 or P=0.01),and the percentages of time of open arm entries were significantly increased (P=0.05 or P<0.01).In the elevated zero maze test,the percentages of number of open arm entries of the mice in 5.0 and 10.0 mg·kg^-1SchB groups were significantly increased compared with blank control group(P<0.01),and the percentages of number of entering open arm probe were significantly increased (P<0.01).Compared with blank control group,the GABA levels in the peripheral blood and brain tissue of the mice in 10.0 mg·kg^-1 SchB group,were significantly increased(P<0.01),the Glu levels in the peripheral blood and brain tissue were significantly reduced(P<0.01),the ratios of GABA/Glu were significantly increased(P<0.01),and the expression levels of GABAARα1 and GABAARγ2 in the brain tissue were significantly increased (P<0.01). Conclusion: SchB has an antianxiety effect in the mice,and the effect may be related to its regulating the levels of GABA and Glu in the peripheral blood and brain tissue and the expression levels of GABAA Rα1 and GABAA Rγ2 in the brain tissue.

Key words: antianxiety, glutamic acid, schisandrin B, γ-aminobutyric acid