IONIC CURRENTS CONTRIBUTING TO THE ACTION-POTENTIAL IN SINGLE VENTRICULAR MYOCYTES OF THE GUINEA-PIG STUDIED WITH ACTION-POTENTIAL CLAMP
IONIC CURRENTS CONTRIBUTING TO THE ACTION-POTENTIAL IN SINGLE VENTRICULAR MYOCYTES OF THE GUINEA-PIG STUDIED WITH ACTION-POTENTIAL CLAMP
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DOI：
10.1007/bf00392058
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发表时间：
1990-05-01
影响因子：
4.5
通讯作者：
TRAUTWEIN, W
中科院分区：
文献类型：
--
作者：
DOERR, T;DENGER, R;TRAUTWEIN, W
用动作电位钳技术研究了不同离子电流对单个心室肌细胞动作电位的影响。动作电位由电流脉冲通过吸移管引起，并由计算机记录。然后在电压钳条件下重复重放同一细胞的代表性动作电位。离子电流的连续药理学阻断首次允许测量L型钙电流（ICa）和[Ca2 +] i激活电流以及钾电流对动作电位的贡献。使用咖啡因作为增加肌浆网钙释放的工具的实验支持这样的观点，即INaCa有助于动作电位后半部分期间的平台期，甚至持续到肌钙素，而动作电位期间细胞内[Ca] i的强烈升高额外激活了非特异性阳离子通道。
With the action potential clamp procedure we studied the contribution of various ionic currents to the action potential in single ventricular myocytes. Action potentials were elicited by a current pulse through the suction pipette and recorded by a computer. A representative action potential was then repetitively replayed to the same cell under voltage-clamp conditions. Successive pharmacological blocks of ionic currents allowed for the first time the measurement of the contribution of the L-type calcium current (ICa) and the [Ca2+]i-activated currents as well as the potassium current to the action potential. Experiments using caffeine as a tool to increase calcium release from the sarcoplasmic reticulum supported the idea that INaCa contributes to the plateau during the second half of the action potential and even lasts into diastole, whereas strong elevation of the intracellular [Ca]i during the action potential additionally activated the non-specific cation channel.