Drug administration
The dried CHSGS extract and fluoxetine (purity >98%; Eli Lilly and Co., Indianapolis, IN, USA) were dissolved in distilled water before administration, respectively. All dosages were expressed as milligrams per kilogram body weight of the respective drugs. The normal group and the model group received only distilled water. Food, but not water, was withdrawn from the animal 1-h prior to drug administration.
The CHSGS extract 5.9 g/kg/day, fluoxetine 1.8 mg/kg/day and distilled water were intragastrically administered to rats of each group respectively at a volume of 4.5 ml/kg/day once daily for consecutive 2 weeks from the 3rd week. The dosage of medicines administered to the rats equaled to that of a 70 kg- adult. In the following studies, open-field test or sucrose consumption test in rats was conducted 1-h after the last drug treatment, respectively.