| Summary: | 碩士 === 中國醫藥大學 === 中國藥學暨中藥資源學系碩士班 === 99 === The aim of the present study was to evaluate the anti-depressive-like effect of ethanol extracts of U. hirsuta Haviland. (UHEtOH), U. lanosa Wallich. var. appendiculata Ridsd. (ULEtOH), U. rhynchophylla (Miq.) Jacks (UREtOH), and commercial crude drug (CDEtOH) for acute or two-weeks administrations by using forced swimming test (FST) and tail suspension test (TST) on mice. In addition, the researcher analysed the content of rhynchophylline in these samples by using high-performance liquid chromatograph (HPLC). In order to understand the potential antidepressant-like effect of ULEtOH in conventional antidepressant models of FST and TST, the levels of monoamines (norepinephrine, serotonin, and dopamine) and the metabolites in mice brain were measured. Moreover, the probable mechanism of anti-depressive effect of ULEtOH was investigated by combining the antidepressant drugs, fluoxetine (FLU, a selective serotonin reuptake inhibitor), imipramine (IMI, a tricyclic antidepressant, monoamine reuptake inhibitor), maprotiline (MAP, selective noradrenaline reuptake inhibitor), clorgyline (CLO, a selective MAO-A inhibitor), bupropion (BUP, selective dopamine reuptake inhibitor), and ketanserin (KET, a preferential 5-HT2A receptor antagonist). Lastly, the effect of ULEtOH on monoamine oxidase activities in mice brain was also evaluated.
The results showed that ULEtOH, UREtOH, and CDEtOH exhibited anti-depressant-like effects in FST and TST in mice, while no central sedative effects were found. The amount of rhynchophylline in CDEtOH, ULEtOH, and UREtOH were 0.86 (mg/g), 17.12 (mg/g), and 3.87 (mg/g), respectively. From this study we inferred that rhynchophylline is the key component of anti-depressant-like effect of CDEtOH, ULEtOH, and UREtOH. ULEtOH (0.25 g/kg, p.o.) increased the levels of 5-HT in cortex and striatum, the level of 5-HIAA in striatum, and the level of MHPG in hippocampus. ULEtOH (0.5 g/kg, p.o.) increased the levels of 5-HT and 5-HIAA in cortex, striatum, hippocampus and hypothalamus, the levels of NE and MHPG in cortex and hippocampus, and the level of NE in striatum. Two-weeks injection of IMI (5.0 mg/kg), CLO (5.0 mg/kg), FLU (5.0 mg/kg), and KET (5.0 mg/kg) enhanced the anti-depressant-like effect of ULEtOH, while MAP (20 mg/kg) and BUP (4.0 mg/kg) did not show the enhancement. In the monoamine oxidase activities test , ULEtOH (0.5 g/kg) inhibited the activity of MAOA.
In conclusion, CDEtOH, ULEtOH, and UREtOH showed anti-depressant-like effects in FST and TST. ULEtOH contained most rhynchophylline among all and had strongest anti-depressant-like effect. The mechanism of anti-depressive-like effect of ULEtOH was mediated by increasing the monoamines level in hippocampus, cortex, striatum, and hypothalamus of mice. Therefore, the researcher inferred that the mechanism of anti-depressive-like effect of ULEtOH was similar to the mechanism of IMI and CLO; furthermore, ULEtOH was proofed to have MAOIA effects.
|
|---|
