Lindblad D S, Murphey C R, Clark J W, Giles W R
Department of Electrical and Computer Engineering, Rice University, Houston 77251-1892, USA.
Am J Physiol. 1996 Oct;271(4 Pt 2):H1666-96. doi: 10.1152/ajpheart.1996.271.4.H1666.
We have developed a mathematical model of the rabbit atrial myocyte and have used it in an examination of the ionic basis of the atrial action potential. Available biophysical data have been incorporated into the model to quantify the specific ultrastructural morphology, intracellular ion buffering, and time- and voltage-dependent currents and transport mechanisms of the rabbit atrial cell. When possible, mathematical expressions describing ionic currents identified in rabbit atrium are based on whole cell voltage-clamp data from enzymatically isolated rabbit atrial myocytes. This membrane model is coupled to equations describing Na+, K+, and Ca2+ homeostasis, including the uptake and release of Ca2+ by the sarcoplasmic reticulum and Ca2+ buffering. The resulting formulation can accurately simulate the whole cell voltage-clamp data on which it is based and provides fits to a family of rabbit atrial cell action potentials obtained at 35 degrees C over a range of stimulus rates (0.2-3.0 Hz). The model is utilized to provide a qualitative prediction of the intracellular Ca2+ concentration transient during the action potential and to illustrate the interactions between membrane currents that underlie repolarization in the rabbit atrial myocyte.
我们已经建立了兔心房肌细胞的数学模型，并将其用于研究心房动作电位的离子基础。已将现有的生物物理数据纳入该模型，以量化兔心房细胞的特定超微结构形态、细胞内离子缓冲以及时间和电压依赖性电流与转运机制。在可能的情况下，描述兔心房中识别出的离子电流的数学表达式基于酶分离的兔心房肌细胞的全细胞电压钳数据。该膜模型与描述Na+、K+和Ca2+稳态的方程相耦合，包括肌浆网对Ca2+的摄取和释放以及Ca2+缓冲。所得公式能够准确模拟其所基于的全细胞电压钳数据，并与在35℃下一系列刺激频率（0.2 - 3.0 Hz）下获得的兔心房细胞动作电位家族相拟合。该模型用于对动作电位期间细胞内Ca2+浓度瞬变进行定性预测，并说明兔心房肌细胞复极化基础的膜电流之间的相互作用。
