Xiaoyaosan The Antidepressant Effect Of The Regulatory Mechanism Of 5-ht System

As the representative prescription of coordinating liver and spleen in Traditional Chinese Medicine,Xiaoyao Powder had the function of relieving the depressed liver, nourishing blood and strengthening the spleen,which was used to cure syndrome of liver depression,blood deficiency and Spleen feebleness.Modern clinical researches indicated that Xiaoyao Powder could improve mental status of depression patients and make them feel happy,comfort and pleasant.These clinical data affirmed the value of Xiaoyao Powder on psychotropic diseases' treatment,but the mechanism was still unclear.In this study, based on its function and clinical uses,tail suspension test(TST),forced swimming test (FST),open-field test in mice,and chronic unpredictable mild stress(CUMS) in rats were adopt to investigate the anti-depression effect of Xiaoyao Powder.Moreover,5-HTP or DOI induced head twitch response(HTR) in mice,the levels of monoamine neurotransmitter in hippocampus or cortex,and the 5-HT_2A receptor protein expression in cortex location in CUMS model rats were observed to study the possible mechanism of anti-depression effect of Xiaoyao Powder.1.Xiaoyao Powder showed anti-depression effect.(1) Xiaoyao Powder could significantly shorten immobility time in TST and FST in mice.The effective dose of Xiaoyao Powder had no effect on open-field test in mice.(2) Successive administration with Xiaoyao Powder for 8 weeks,sucrose consumption, numbers of standing and crossing could be increased in CUMS model rats.And it also alleviated weight losing in CUMS model rats.2.Influences on 5-HT system of Xiaoyao Powder maybe related to its mechanism of anti-depression effect.(1) Xiaoyao Powder decreased the number of HTR caused by 5-HTP and DOI in mice. Furthermore,this effect was attenuated when the dose of DOI was increased in DOI induced HTR in mice.(2) Successive administration with Xiaoyao Powder for 8 weeks,concentration of 5-HT in cortex and 5-HIAA in hippocampus in CUMS model rats could be increased.(3) Successive administration with Xiaoyao Powder for 8 weeks,the 5-HT_2A receptor protein expressions in cortex in CUMS model rats showed the decreasing tendency.Taken together,these results suggest that Xiaoyao Powder has anti-depression effect, which probably via 5-HT system in brain,especially the 5-HT_2A receptor.