盐酸小檗碱对甲状腺素性豚鼠心肌病心肌细胞中I Kr ， IKs和IK1的抑制作用
Inhibition of berberine on I Kr ，I Ks and I K1 in thyroxine induced cardiomyopathic guinea pig ventricular myocytes
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摘要: 目的 ： 研究盐酸小檗碱(berberine，Ber)对甲状腺素性豚鼠心肌病中延迟整流外向钾电流中快激活成分(I Kr )和慢激活成分(I Ks )及内向整流电流(I K1)的抑制作用。 方法 ： 豚鼠腹腔注射L-甲状腺素造成心肌病后，分离单个心肌细胞，用全细胞膜片钳技术记录钾电流。 结果 ： 在心肌病细胞的I Kr ，I Ks 和IK1电流密度均明显增大，Ber 30 mmol/L分别抑制心肌病细胞I Kr 22.8%（+10 mV）和I Ks 29.5%（+80 mV），其对I Ks 的阻断作用大于I kr 。Ber 30 mmol/L也能阻断心肌病细胞I K129.1%（+120 mV），但不影响其反转电位。Ber(1~300 mmol/L）浓度依赖性地阻断心肌病细胞I Kr 及I Ks ，其IC50分别为76 mmol/L和55.37 mmol/L。 结论 ： 甲状腺素性心肌病中出现异常增大的I Ks ，I Kr 及I K1离子流，Ber有明显阻断作用。Abstract: Aim ：To study the effects of berberine(Ber) on the rapidly activating component(I Kr )，the slowly activating component(I Ks) of the delayed rectifier potassium current and the inward rectifier potassium current(I K1) in cardiomyopathic guinea pig ventricular myocytes. Methods ：After guinea pigs were ip L-thyroxine 0.5 mg/kg for 10 d，their hearts were cardiomyopathic.Then whole cell patch-clamp recording technique was used to observe the effect of 30 μmol/L Ber on the I Kr ，I Ks and I K1in cardiomyopathic guinea pig ventricular myocytes. Results ：In cardiomyopathic guinea pig ventricular myocytes，Ber 30 μmol/L markedly inhibited I Kr and I Ks by 22.8% and 29.5% at +10 mV and +80 mV，respectively.The effect of Ber on I Ks was greater than that on I Kr .Ber 30 μmol/L also inhibited the inward component of I K1 by 29.1% at+120 mV，but the reverse potential of I K1was unaffected.Ber(1- 300 μmol/L) was shown to inhibit I Kr and I Ks in a concentration-dependent manner.Their IC50 were 76.74 μmol/L and 55.37 μmol/L，respectively. Conclusion ：Ber inhibited I Kr ，I Ks and I K1in cardiomyopathic guinea pig ventricular myocytes，which may be important in understanding the antiarrhythmic effects of this drug.
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Keywords:
- berberine /
- thyroxine /
- cardiomyopathy /
- I Ks /
- I Kr /
- I K1 /
- patch clamp techniques
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