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虎杖甙对正常人血管平滑肌细胞内钙和膜电位的调节作用 |
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金春华 赵克森
摘 要 目的和方法：观察虎杖甙(PD)对人脐带动脉平滑肌细胞(VSMC)内游离钙、细胞膜电位的变化，以探讨PD对血管平滑肌的调节机制。用Fluo-3-AM、DiBAC4(3)标记培养的VSMC，在激光共聚焦显微镜上测定细胞内游离钙和膜电位变化。结果：给PD(0.5 mmol/L)10 min后，VSMC内游离钙浓度升高56%±5.6%。当PD加入前用维拉帕米和EGTA预处理后，则游离钙不再升高；EGTA和肝素预处理也抑制PD的升钙作用，而EGTA和普鲁卡因预处理则使细胞内钙显著升高。PD还可使VSMC膜电位去极化，加入钠通道阻断剂河豚毒素(2.5 μmol／L)可完全阻断PD的去极化作用：加甲氰咪胍、维拉帕米、优降糖和利及丁预处理不能阻断PD去极化作用。结论：：PD可通过细胞外钙内流来增加细胞内游离钙浓度，并促进细胞外钠离子内流而导致细胞去极化。
主题词 肌，平滑，血管；钙；膜电位
The regulation of Polydatin on intracellular free calcium and membrane potential of human vascular smooth muscle cells
JIN Chun-Hua,ZHAO Ke-Sen
Department of Pathophysiology， First Military Medical University,Guangzhou(510515)
Abstract AIM：The present study was to investigate the regulation mechanism of Polydatin on human blood vessels.METHOD：The changes of the cytosolic free calcium concentration and cell membrane potential of cultured vascular smooth muscle cells (VSMC) were determined kinetically between passages 3 and 8 isolated from human umbilicus artery.RESULTS：Polydatin (0.5 mmol/L) caused a persistent increase of intracellular calcium concentration ［Ca2＋］i,which was inhibited completely by pretreatment with EGTA(2 mmol/L) and verapamil(50 μmol/L)10 min prior to Polydatin givening,and was also blocked completely by pretreatment with EGTA and heparin(765×103 U/L).But the effect of polydatin on ［Ca2＋］i was enhanced by pretreatment with EGTA and procaine(10 mmol／L).Polydatin can also make the cell membrane potential less negative or depolarized 10 min after polydatin adding.The effects of Polydatin were enhanced significantly by pretreatment with cimetidine,but it was inhibited completely by pretreatment with tetrodotoxin(2.5μmol/L),a kind of sodium channel blocker CONCLUSIONS：Polydatin-induced alternation in［Ca2＋］i might be mainly due to the entry of extracellular Ca2+ into cells and release from IP3 sensitive intracellular calcium store,and ryanodine recepto[1] [2] 下一页
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