【摘要】 目的:探讨马钱子碱(brucine)对大鼠心室肌细胞瞬时外向钾电流(transient outward potassium current,Ito)及其动力学的影响。方法:用酶解法分离大鼠单个心室肌细胞。用全细胞膜片钳技术记录不同浓度的马钱子碱可对大鼠心室肌细胞Ito的前后影响变化。结果:①马钱子碱可浓度依赖性地阻断Ito;②5μmol/L的马钱子碱可使Ito稳态激活曲线右移,V1/2由对照的(-30.7±10.2)mV变为(-27.8±5.8)mV(P<0.05);③5μmol/L的马钱子碱可使Ito稳态失活曲线左移,V1/2分别为(-41.6±1.0)mV变为(-75.0±2.8)mV(P<0.05);④5μmol/L的马钱子碱可使Ito稳态激活曲线右移失活后再恢复时间常数τ延长。结论:提示马钱子碱可以阻断Ito,对Ito的激活态和失活态均具有较高的亲和力,这些可能是其抗心律失常作用的机制。更多还原

【Abstract】 AIM: To explore the effects of brucine on transient outward potassium current(Ito) of ventricular cardiomyocytes of rats.METHODS: Single ventricular myocytes of rats were obtained by enzymatic dissociation.The whole-cell patch-clamp recording technique was used to record the changes of Ito by different dosages of brucine.RESULTS: Brucine significantly reduced Ito in a concentration-dependent manner.Brucine at 5 μmol/L shifted the stabilized activation curve to the right and the half-point of actiation potential(V1/2) from(30.7±10.2) mV to(27.8±5.8) mV(n=8,P<0.05).Brucine(5 μmol/L) shifted the stabilized deactivation curve to the left and the half-point of actiation potential(V1/2) from(41.6±1.0) mV to(75.0±2.8) mV(n=8,P<0.05).Brucine(5 μmol/L) significantly prolonged the recovery time.CONCLUSION: Brucine has significant inhibitive effects on Ito,which may be one of the mechanisms that underlie its antiarrhythmic effect.更多还原