Uttenweiler D, Weber C, Fink R H
Ruprecht-Karls-Universität Heidelberg, II Institute of Physiology, Germany.
Biophys J. 1998 Apr;74(4):1640-53. doi: 10.1016/S0006-3495(98)77877-4.
A mathematical model was developed for the simulation of the spatial and temporal time course of Ca2+ ion movement in caffeine-induced calcium transients of chemically skinned muscle fiber preparations. Our model assumes cylindrical symmetry and quantifies the radial profile of Ca2+ ion concentration by solving the diffusion equations for Ca2+ ions and various mobile buffers, and the rate equations for Ca2+ buffering (mobile and immobile buffers) and for the release and reuptake of Ca2+ ions by the sarcoplasmic reticulum (SR), with a finite-difference algorithm. The results of the model are compared with caffeine-induced spatial Ca2+ transients obtained from saponin skinned murine fast-twitch fibers by fluorescence photometry and imaging measurements using the ratiometric dye Fura-2. The combination of mathematical modeling and digital image analysis provides a tool for the quantitative description of the total Ca2+ turnover and the different contributions of all interacting processes to the overall Ca2+ transient in skinned muscle fibers. It should thereby strongly improve the usage of skinned fibers as quantitative assay systems for many parameters of the SR and the contractile apparatus helping also to bridge the gap to the intact muscle fiber.
建立了一个数学模型，用于模拟化学去表皮肌纤维制剂中咖啡因诱导的钙瞬变过程中Ca2+离子运动的时空变化过程。我们的模型假设为圆柱对称，通过用有限差分算法求解Ca2+离子和各种移动缓冲剂的扩散方程，以及Ca2+缓冲（移动和固定缓冲剂）以及肌浆网（SR）对Ca2+离子的释放和再摄取的速率方程，来量化Ca2+离子浓度的径向分布。将该模型的结果与通过使用比率染料Fura-2的荧光光度法和成像测量从皂素去表皮的小鼠快肌纤维获得的咖啡因诱导的空间Ca2+瞬变进行比较。数学建模和数字图像分析的结合为定量描述去表皮肌纤维中总Ca2+周转以及所有相互作用过程对整体Ca2+瞬变的不同贡献提供了一种工具。因此，它应该会大大改善将去表皮纤维用作SR和收缩装置许多参数的定量测定系统的用途，也有助于弥合与完整肌纤维之间的差距。
