Apple procyanidins induce hyperpolarization of rat aorta endothelial cells via activation of K+ channels
Apple procyanidins induce hyperpolarization of rat aorta endothelial cells via activation of K+ channels
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DOI：
10.1016/j.jnutbio.2010.12.005
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发表时间：
2012-03-01
影响因子：
5.6
通讯作者：
Matsui, Toshiro
中科院分区：
文献类型：
--
作者：
Byun, Eui-Baek;Korematsu, Sachiko;Matsui, Toshiro
苹果原花青素(AP)是一种富含多酚的化合物，具有内皮依赖性的血管松弛作用，但其作用机制尚不清楚。本研究旨在阐明AP在大鼠主动脉内皮细胞(RAECs)中的潜在作用。AP(1~10mU g/ml)作用于RAECs后，表现出剂量依赖性的超极化效应，在10mU g/ml时作用最大，因此在所有实验中都使用了AP(10mU g/ml)。非特异性K+阻滞剂、四乙基氯化铵或特异性K+通道阻滞剂、伊贝里奥毒素、格列本脲、4-氨基吡啶和BaCl2预处理，以及高KCI或无钙溶液均可显著抑制AP诱发的超极化。通道多电极培养系统也证实了AP诱发的超极化效应，该系统可以直接实时监测膜电位的变化。更重要的是。AP可通过内皮型一氧化氮合酶信使RNA的表达，显著增加内皮型一氧化氮合酶(NO)的生成和环磷酸鸟苷的水平。N-G-单乙基-L-精氨酸或无钙溶液均可抑制NO的产生，但两者合用可完全抑制NO的产生。AP抑制血管内皮细胞增殖，其作用可被N-G-单乙基-L-精氨酸或四乙基氯化铵显著拮抗。这些结果提示AP通过激活多种K+通道诱导RAECs超极化，并通过增加NO的产生而激活NO/环鸟苷一磷酸通路，或参与抗血管生成作用。AP在无钙溶液中超极化的减弱和NO的产生，提示AP可能在促进内皮细胞内钙内流中起关键作用，从而促进这两种作用。2012 Elsevier Inc.保留所有权利。
Apple procyanidins (AP), one of the polyphenol-rich compounds, showed an endothelial-dependent vasorelaxation in rat aorta, but the mechanisms of beneficial effects are still unclear. The present study was designed to clarify the potential role of AP in rat aorta endothelial cells (RAECs). The treatment of RAECs with AP (1-10 mu g/ml) resulted in a dose-dependent hyperpolarization with a maximum effect at 10 mu g/ml, and for this reason, AP (10 mu g/ml) was used in all the following experiments. AP-induced hyperpolarization was significantly inhibited by pretreatment of nonspecific K+ inhibitor, tetraethyl ammonium chloride or specific K+ channel inhibitors, iberiotoxin, glibenclamide, 4-aminopyridine and BaCl2, as well as by high KCI or Ca2+-free solution. AP-induced hyperpolarization was also proved using 64-channel multielectrode dish system that can monitor a direct and real-time change of membrane potential. Furthermore. AP treatment caused a significant increase of nitric oxide (NO) production and cyclic guanosine monophosphate levels via endothelial NO synthase messenger RNA expression. The NO production was inhibited by N-G-monoethyl-L-arginine or Ca2+-free solution and was completely abolished by their combination. Also, AP inhibited endothelial proliferation, while the effect was significantly abolished by N-G-monoethyl-L-arginine or tetraethyl ammonium chloride. These findings suggest that AP induces both hyperpolarization of RAECs via multiple activation of K+ channels and activation of NO/cyclic guanosine monophosphate pathway via increasing NO production or is responsible for antiangiogenic effect. Diminishment of hyperpolarization as well as NO production of AP in Ca2+-free solution implicated that AP would play a crucial role in promoting Ca2+ influx into endothelial cells so as to promote both actions. 2012 Elsevier Inc. All rights reserved.