Objective: To study the sedative and hypnotic effects of Gandan Liangyi Tang (GDLYT) and the potential mechanism in mice. Method: The KM mice were divided into seven groups:control group

diazepam group

Bailemian group

GDLYT 5.2

2.6

1.3

0.65 g·kg-1 dose groups

and mice were administrated once per day. The threshold dose of pentobarbital sodium was observed in mice. The locomotion activity was estimated

and the rotarod test was used to evaluate the effects of GDLYT. The contents of amino acids neurotranmitters including aspartic acid (Asp)

glutamic acid (Glu)

glycine (Gly)

γ-aminobutyric acid (GABA) in mice brain were determined by HPLC-FL. Result: The results showed that administration of GDLYT at 2.6

1.3 g·kg-1·d-1 significantly shorted the latency period and lengthened the duration of sleep(P<0.05 or P<0.01). Besides

the locomotion activities were significantly reduced by GDLYT (1.3

2.6 g·kg-1·d-1)(P<0.05 or P<0.01)while the coordination of motion was no changed in mice after GDLYT treated. The results of HPLC indicated that GDLYT 5.2 g·kg-1group can significantly increase the GABA

Asp and the Glu content(P<0.05 or P<0.01)

and the 2.6 g·kg-1group could increase the GABA and Gly content significantly(P<0.05 or P<0.01)

meanwhile the 1.3 g·kg-1 group could significantly increase the content of GABA (P<0.01)in the mice brain tissues. Conclusion: Our results suggested that GDLYT exerts sedative and hypnotic activities

and the mechanisms may be correlated with the effects of increasing the contents of amino acids neurotranmitters GABA and Gly.