Effects of ginsenoside Rg₁ on synaptic plasticity of freely moving rats and its mechanism of action  

人参皂甙Rg1对自由活动大鼠突触可塑性的影响及其作用机制<英文>

作　　者：王晓英[1] 张均田[1] 

机构地区：[1]中国医学科学院中国协和医科大学药物研究所药理研究室,北京100050

出　　处：《Acta Pharmacologica Sinica》2001年第7期83-88,共页中国药理学报（英文版）

摘　　要：AIM: To investigate the effect and mechanism of gin-senoside Rg1 on synaptic plasticity of freely moving rats. METHODS: SD rats were chronically implanted with a stimulation electrode in the perfbrant path (PP) of hippocampus and a recording electrode in the granule cell of dentate gyrus. After administration of ginsenoside Rg1 (10, 30 mg/kg, ip) for 12 d, extracellular recording technique was used to record the population spike (PS). Mossy fiber (MF) sprouting was measured using Timm’s staining, and an immunohistochemical technique was used to detect the expression of presynaptic growth-associated protein 43 (GAP-43). RESULTS: Rg1 could significantly increase the sensitivity of evoking PS, the amplitude of PS and induce PP-DG long-term potentiation (LTP) in the dentate gyrus (DG) of freely moving rats. In the meantime, Rg1 accelerated MF sprouting in CA3 cell field of hippocampus. The expression level of GAP-43 was elevated in granule cell layer and hilus of DG of Rg1 -treated rats. CONCLUSION: The increased synaptic plasticity may attribute to the increased expression of GAP-43 in granule cell layer of DG and the onset of the sprouting of granule cell axon-MF. The MF sprouting accelerated the synaptic transmission in positive-feedback. Their interaction and the synergism is part of the mechanisms underlying the nootropic effect of Rg1.目的:研究人参皂甙Rg₁对自由活动大鼠突触功能可塑性的影响及作用机制。方法:应用细胞外微电极记录技术,大鼠埋植电极后d6予以Rg₁（10,30mg/kg,ip）12d,记录（直至停药后d3）其齿状回群体峰电位（PS）。大鼠给予Rg₁（10,30mg/kg,ip）12d,据Timm染色法观察海马CA3区苔辞纤维出 芽情况。以免疫组化技术检测齿状回颗粒细胞层GAP-43表达水平。结果:1)Rg₁可显著降低诱发PS的阈值,提高清醒自由活动大鼠的突触传递效能,诱导LTP形成,停药3d后,LTP仍可维持。2)Rg₁组大鼠齿状回颗粒细胞层及齿状回门区GAP-43表达显著增加。3)Timm染色显示海马CA3区苔藓纤维出芽增加。结论:Rg₁可使自由活动大鼠PP-DG突触传递效能发生以LTP为主的可塑性变化,其机制为齿状回颗粒细胞GAP-43表达增加,其投射靶区海马CA3苔藓纤维明显出芽增加,这呈正反馈性增强了突触传递效能。

关 键 词：GINSENG SAPONINS long-term potentia- tion synapses dentate gyrus GAP-43 protein 

分 类 号：R9[医药卫生—药学]