Department of Pharmacology, College of Pharmacy, Beihua University, East Binjiang Road 3999, Jilin, China.
Department of Pharmacology, College of Pharmacy, Beihua University, East Binjiang Road 3999, Jilin, China.
Life Sci. 2020 Mar 15;245:117357. doi: 10.1016/j.lfs.2020.117357. Epub 2020 Jan 25.
Schisandra is a good choice in Traditional Chinese Medicine for the therapy of cardiovascular diseases, but whether it contains a or some specific component (s) responsible these effects are still unclear. In the present study, we explored whether Schisantherin A (SCA) causes vasorelaxation in isolated rat thoracic aorta.
We selected SCA, one of the main monomers of lignans from Schisandra, to examine its vasorelaxant effect on the isolated rat thoracic aorta and also exploited several tool inhibitors to probe its underlying mechanisms.
SCA produced relaxation concentration-dependently on the endothelium-intact (43.56 ± 2.17%) and endothelium-denuded thoracic aorta strips (18.76 ± 3.95%) pre-contracted by phenylephrine (PE). However, after treated with indomethacin or L-NAME, SCA showed only partial vasorelaxant effects. Whereas, this vasorelaxation by SCA was not changed with specific K-channel inhibitors, i.e. barium chloride (BaCl), 4-aminopyridine (4-AP), tetraethylamine (TEA), and glibenclamide. SCA had no effect on the aorta strips pre-contracted by PE in neither Ca-free nor CaCl conditions. But, in the Ca free and high K environment, SCA partly abolished the vasocontraction induced by CaCl.
It was the first report to demonstrate that SCA had endothelium-dependent and -independent vasorelaxant effects on the isolated rat thoracic aorta, and the underlying mechanisms might be involved into its promoting the production of nitric oxide (NO) and prostacyclin (PGI), and inhibiting the voltage-dependent calcium channels (VDCCs) opening. This study may partially explain the use of Schisandra in cardiovascular diseases and facilitate further drug development as well.
五味子是治疗心血管疾病的中药的不错选择，但它是否含有一个或某些特定成分（s）负责这些效果仍不清楚。在本研究中，我们探讨了五味子甲素（SCA）是否引起离体大鼠胸主动脉舒张。
我们选择了 SCA，这是五味子中主要的木脂素单体之一，来检查它对离体大鼠胸主动脉的舒张作用，并利用几种工具抑制剂来探究其潜在机制。
SCA 对内皮完整（43.56±2.17%）和去内皮的胸主动脉条（18.76±3.95%）均产生浓度依赖性的舒张作用，这些主动脉条预先用苯肾上腺素（PE）收缩。然而，在用吲哚美辛或 L-NAME 处理后，SCA 只显示出部分舒张作用。然而，这种 SCA 的舒张作用不受特定的 K 通道抑制剂的影响，即氯化钡（BaCl）、4-氨基吡啶（4-AP）、四乙胺（TEA）和格列本脲。SCA 对 PE 预收缩的主动脉条在无钙或 CaCl 条件下均无作用。但是，在无钙和高 K 环境中，SCA 部分消除了由 CaCl 引起的血管收缩。
这是第一个报道表明 SCA 对离体大鼠胸主动脉具有内皮依赖性和非依赖性的舒张作用，其潜在机制可能涉及促进一氧化氮（NO）和前列环素（PGI）的产生，以及抑制电压依赖性钙通道（VDCCs）的开放。本研究可能部分解释了五味子在心血管疾病中的应用，并有助于进一步的药物开发。
