【作者】 黄峥嵘；

【导师】 唐其柱； 史锡腾；

【作者基本信息】 武汉大学 ， 生物医学工程， 2004， 硕士

【摘要】 目的：研究缬草提取物（VE）对兔心室肌细胞跨膜动作电位时程（APD）、钠电流(I_Na)、L-钙电流(I_Ca-L)、短暂外向钾电流(I_to)、延迟整流钾电流（I_K）、内向整流钾电流(I_Kl)、三磷酸腺苷敏感性钾电流(I_KATP)的影响，以探讨其抗心律失常作用的细胞电生理机制。 方法：使用酶解法分离单个兔心室肌细胞。采用全细胞膜片钳技术，在电压钳模式下记录不同浓度VE对I_Na、I_Ca-L、I_to、I_K、I_Kl、I_KATP的影响。在电流钳模式下观察跨膜动作电位的变化。 结果：① 30μg／L、60μg／L缬草提取物（VE）可使动作电位时程（APD）明显缩短，APD₅₀和APD₉₀分别由给药前的（352±27）ms和（416±33）ms缩短至（257±24）ms、（168±20）ms和（316±31）ms、（265±23）ms，分别缩短了27.0％、52.2％和24.0％、35.6％（n=16，p＜0.05），而动作电位幅值无明显改变；② 30μg／L和60μg／L的VE使兔心室肌细胞I_Na峰值(I_Namax)从（53.47+5.13）pA／pF分别降至（40.25+4.18）pA／pF和（30.89+2.95）pA／pF（n=8，p＜0.05和p＜0.01），抑制率分别为24.7％和41.9％；VE使I_Na的电流-电压曲线上移，但不改变其激活电位、电位峰值和反转电位；VE还减慢钠通道灭活后的恢复过程；③ 30μg／L和60μg／L的缬草提取物（VE）使兔心室肌细胞I_Ca-L峰值(I_Ca-Lmax)由（6.04±0.59）pA／pF分别减至（3.99+0.31）pA／pF和（2.31+0.24）pA／pF，抑制率分别为33.9％和57.1％（n=8，p＜0.01）；VE使I_Ca-L的电流-电压曲线上移，但不改变其激活电位、电位峰值和反转电位；VE还使钙电流失活曲线左移；④ 在刺激电压+60mV时，60μg／L和120μg／L的缬草提取物（VE）使瞬时外向钾电流(I_to)幅值从（4.6±0.42）pA／pF分别降至（2.8±0.23）pA／pF和（1.7±0.14）pA／pF（n=7，p均＜0.01），抑制率分别为39.1％和63.0％；⑤ 缬草提取物（VE）对延迟整流钾电流（I_K）、内向整流钾电流(I_Kl)的电流幅值和电流-电压曲线的影响不明显（n=7，p＞0.05）；⑥ 不同浓度VE均不能引出三磷酸腺苷敏感性钾电流(I_KATP)。 结论：缬草提取物（VE）能明显缩短动作电位时程（APD）；缬草提取物（VE）浓度依赖性抑制I_Na、I_Ca-L、I_to；缬草提取物（VE）对I_K、I_Kl、I_KATP无明显影响，对I_KATP无直接开放作用。VE对抗心律失常作用可能与其对上述离子通道的影响有关。更多还原

【Abstract】 Objective: To investigate the effects of valerian extract (VE) on action potential duration(APD), sodium current(INa), L-calcium current (Ica-L),transient outward potassium current(Ito), delayed rectifier potrssium current(IK) inward rectifier potassium current(IKl) and adenosine triphosphate-sensitive potassium current (Ikatp) in isolated rabbit ventricular myocytes.Methods: Single rabbit’s ventricular myocytes were isolated with enzyme. The whole-cell patch clamp recording technique was used to observe the changes of action potential duration(APD) , sodium current(INa), L-calcium current (ICa-L),transient outward potassium current(Ito), delayed rectifier potassium current(IK), inward rectifier potassium current(IK1) and adenosine triphosphate-sensitive potassium current (Ikatp) under different concentration of VE.Results: (1)30 ug/L VE, 60 u g/L VE could shortened APD50 and APD90 from (352 ±27)ms to (257±24) ms, (168±20)ms, and (416±33)ms to (316±31)ms, (265 ± 23)ms(27.0%, 52.2%; 24.0%,35.6%, n=16, p<0.05) respectively, but had no significant effect on action potential amplitude.(2)VE at 30,60 u g/L decreased peak INa (INamax) from (53.47±5.13)pA/pF to(40.25±4.18)pA/pF and (30.89±2.95)pA/pF (24.7%,41.9%, n=8, p<0.05 and p<0.01), respectively.VE upshifted the INa I-V curves of without changes of their active, peak and reverse potentials; VE at 60 u g/L turned the steady-state inactication curve to right.(3)VE at 30,60 u g/L decreased peak ICa-L (Ica-Lmax) from (6.04±0.59)pA/pF to(3.99±0.31)pA/pF and(2.31±0.24)pA/pF (33.9%,57.1%, n=8, p<0.01), respectively.VE upshifted the I-V curves of Ica-L without changes of their active, peak and reverse potentials; (4)At 60mV, VE at 60 u g/L and 120 u g/L decreased Ito current amplitude from( 4.6±0.42) pA/pF to (2.8±0.23) pA/pF and (1.7±0.14) pA/pF(n=7, p<0.01,respectively);(5)VE did not inhibit Ik, Ik1 with no change on reversal-potential(n=7,p>0.05).(6) VE did not induce Ikatp directly.Conclusion: VE shortened APD in dose-dependent ;VE blocks INa in a concentration dependent manner and probably inhibits Ina in its inactive state ; VE blocks Ica-L manner and probably inhibits Ica-L in its inactive state ; VE inhibited Ito in a concentration dependent ;these could be the important mechanisms of its antiarrhythmic and its cardioprotective effects.更多还原