A DYNAMIC-MODEL OF THE CARDIAC VENTRICULAR ACTION-POTENTIAL .2. AFTERDEPOLARIZATIONS, TRIGGERED ACTIVITY, AND POTENTIATION
A DYNAMIC-MODEL OF THE CARDIAC VENTRICULAR ACTION-POTENTIAL .2. AFTERDEPOLARIZATIONS, TRIGGERED ACTIVITY, AND POTENTIATION
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DOI：
10.1161/01.res.74.6.1097
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发表时间：
1994-06-01
影响因子：
20.1
通讯作者：
RUDY, Y
中科院分区：
文献类型：
--
作者：
LUO, CH;RUDY, Y
我们在本期杂志上发表的文章中提出的动作电位模型用于研究涉及[Ca2+](i)动态变化的现象，如下所述。延迟后去极化（DADs）是由肌浆网（SR）自发Ca2+释放引起的，这反过来又激活了Na+-Ca2+交换器（I-NaCa）和非特异性Ca2+激活电流（I-ns(Ca)）。不同Ca2+超载程度下，I-NaCa和I-ns（Ca）对DADs生成的相对贡献是不同的。早期后去极化（EADs）可分为两种类型：(1)平台型EADs，由动作电位平台期间l型Ca2+电流的二次激活引起；(2)第三阶段EADs，由[Ca2+]增加引起i - naca和i -ns（Ca）的激活引起；(i)由于SR在复极化后期自发释放Ca2+。自发节律活动和触发活动是由Ca2+过载条件下SR的自发Ca2+释放引起的。收缩后电位增强反映了Ca2+从网络SR转移到连接SR的时间延迟，细胞在高频率下进行节奏以研究对细胞内离子浓度的长期影响。
The action potential model presented in our accompanying article in this journal is used to investigate phenomena that involve dynamic changes of [Ca2+](i), as described below. Delayed afterdepolarizations (DADs) are induced by spontaneous Ca2+ release from the sarcoplasmic reticulum (SR), which, in turn, activates both the Na+-Ca2+ exchanger (I-NaCa) and a nonspecific Ca2+-activated current (I-ns(Ca)). The relative contributions of I-NaCa and of I-ns(Ca) to the generation of DADs are different under different degrees of Ca2+ overload. Early afterdepolarizations (EADs) can be categorized into two types: (1) plateau EADs, resulting from a secondary activation of the L-type Ca2+ current during the plateau of an action potential, and (2) phase-3 EADs, resulting from activation of I-NaCa and I-ns(Ca) by increased [Ca2+](i) due to spontaneous Ca2+ release from the SR during the late repolarization phase. Spontaneous rhythmic activity and triggered activity are caused by spontaneous Ca2+ release from the SR under conditions of Ca2+ overload. Postextrasystolic potentiation reflects the time delay associated with translocation of Ca2+ from network SR to junctional SR, The cell is paced at high frequencies to investigate the long-term effects on the intracellular ionic concentrations.