| Summary: | 碩士 === 國立陽明大學 === 藥理學研究所 === 88 === Benzodiazepines and 5-HT1A receptor agonists have been used for treating anxiety disorder. Previous receptor binding assays indicated that the water extracts of CNS-active Chinese herbal drugs Aiye, Huanglin, Huangqin, and Wuzhuyu contain the active principle(s) acting on the benzodiazepine binding site of GABAA receptors or/and 5-HT1A receptors. Therefore, it is interesting to examine whether these water extracts have anxiolytic effects in a rat Vogel conflict test. The results showed that Aiye (0.01-1.5 g/kg, i.p.), Huanglian (0.1-0.5 g/kg, i.p.) and its active principle berberine (4.0 and 8.0 mg/kg, i.p.), and Huangqin (0.1-0.5 g/kg, i.p.), increased the numbers of punishment accepted in the Vogel lick-shock conflict paradigm over 9 min, as did chlordiazepoxide (5.0 mg/kg, i.p.) and 8-OH DPAT (0.5 mg/kg, i.p.). In the test doses (0.1-5.0 g/kg, i.p.), Wuzhuyu had no significantly anxiolytic effect. The effects of Aiye, Huanglian, berberine, and Huangqin were unlikely due to enhanced thirst and shock tolerance as their treatments did not change the total volume of water intake and the shock sensitivity to rat. The anxiolytic effect of Aiye, Huanglian, and Huangqin, but not berberine, could be antagonized by co-administration of a 5-HT1A/b-adrenergic receptor antagonist pindolol (10 mg/kg). However, an a2-adrenoceptor antagonist yohimbine (1.5 and 4.5 mg/kg, i.p.) could antagonize the anxiolytic effect of berberine. In conclusion, the present study demonstrated for the first time that anxiolytic effects of Aiye, Huanglian, and Huangqin water extracts probably mediated through activation of 5-HT1A receptors and that of berberine through activation of a2-adrenoceptors.
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