金丝桃甙对钙离子内流的影响

THE BLOCKING EFFECT OF HYPERIN 0N THE INW ARD FLOW OF CAI IUM ION

摘要: 研究表明,金丝桃甙(HyP)对兔乳头肌模型,与维拉帕米(Ver)一样,呈剂量依赖性抑制CaCl₂诱发的正性肌力作用,使CaCl₂的量-效曲线显著右下移动,但不平行,可能系非竞争性拮抗;对豚鼠心室肌动作电位模型,Hyp可显著缩短动作电位二相平台期,而对膜静息电位、动作电位零相上升幅度和速率及动作电位时程无明显影响;在小鼠心房组织标本上,Hyp和Ver一样,可抑制高钾诱发的45Ca内流。上述结果提示Hyp对钙内流有一定阻滞作用。

Abstract: Hyperin(Hyp)was shown to inhibit the positive inotropic action of calcium ion onthe isolated papillary muscles and shift the dose response curve of calcium ion to the right.As a plotlg(x一1)us一lg(B)resulted in straight lines with slopes of一0.625.On the action potentials ofguinea pig myocardical cells,Hyp markedly decreased the duration of plateau of action potentials(APD_20%)but did not influence the APD_100%, RP,APA,OS and Vmax.In the atrium preparationsof mice, Hyp significantly inhibited influx of ⁴⁵Ca induced by high K⁺,All findings indicate that Hypcan inhibit the in ward flow of calcium ion.