| Summary: | 碩士 === 國立陽明大學 === 藥理學研究所 === 90 === Abstract
The anxiolytic-like effects of water extracts from Chinese herbal drugs Aiye, Huanglian (also its active principle berberine), and Huangqin were previously demonstrated by the Vogel test in rats. In this study, the mice were used as the animal model to re-evaluate their anxiolytic-like effects and the possible underlying mechanisms of action. The anxiolytic-like effects of Huangqin flavones wogonin, baicalin and baicalein were also examined. Unlike the results from the Vogel test in rats, the present results showed that Aiye (0.01-1.5 g/kg, i.p.), Huanglian (0.02-0.5 g/kg, i.p.), and Huangqin (0.02-1.0 g/kg, i.p.) had no significant anxiolytic-like effects in mice because they were unable to increase the number of shocks accepted in the Vogel lick-shock conflict paradigm over 9 min. Wogonin (5.0-20.0 mg/kg, i.p.) also had no significant anxiolytic-like effect in mice. However, berberine (3.0 mg/kg, i.p.), baicalin (20.0 mg/kg, i.p.) and baicalein (10.0 mg/kg, i.p.) had significant anxiolytic-like effects. The anxiolytic-like effects of berberine, baicalein, and baicalin could not be antagonized by co-administration of 5-HT1A/β-adrenergic receptor antagonist pindolol (10.0 mg/kg, i.p.), but that of baicalin and baicalein could be antagonized by the co-administration of a benzodiazepine antagonist flumazenil (1.0 and 2.0 mg/kg, i.p.) and that of berberine and baicalein could be antagonized by the co-administration of an α2-adrenoceptor antagonist yohimbine (1.5 mg/kg, i.p.). Receptor binding assay showed that berberine had affinity for the α2-adrenoceptors but baicalein had no significant affinity. Therefore, the present study demonstrated for the first time that beberine, baicalin, and baicalein have anxiolytic-like effects in mice and the anxiolytic-like effect of berberine appears to involve the activation of the α2-adrenoceptors.
|
|---|
