Effect of Ca2+ influx on intracellular free Ca2+ responses in antigen-stimulated RBL-2H3 cells.
Effect of Ca2+ influx on intracellular free Ca2+ responses in antigen-stimulated RBL-2H3 cells.
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DOI：
10.1152/ajpcell.1996.270.3.c939
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发表时间：
1996-03
期刊：
影响因子：
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通讯作者：
G. Smith;R. J. Lee;J. Oliver;J. Keizer
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文献类型：
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作者：
G. Smith;R. J. Lee;J. Oliver;J. Keizer
我们对抗原刺激的大鼠嗜碱性白血病（RBL-2 H3）细胞内游离Ca ~（2+）浓度（[Ca ~（2+）]i）的变化进行了定量研究，其中包括Ca ~（2+）库释放和Ca ~（2+）内流的贡献。继Keizer和De Young（J. Keizer和G.德扬。Biophys. J.61：649-660，1992），我们开发了RBL-2 H3细胞中[Ca 2 +]i振荡的高度约束的数学模型，其包括通过1，4，5-三磷酸肌醇激活三磷酸肌醇受体（IP 3R），通过磷脂酶C-γ的Ca 2+依赖性活性间接Ca 2+激活IP 3R，通过胞质Ca 2+缓慢抑制IP 3R，Ca 2 + -ATP酶（SERCA）型泵的Ca 2+库的再填充，以及质膜（PM）通量对实验条件的依赖性的简单表示。使用这个完整的（开放细胞）模型，我们模拟[Ca 2 +]i的反应，其中抗原浓度和外部Ca 2+的操作和比较的计算与实验数据的协议。在方案A中，在存在外部Ca 2+的情况下刺激细胞，在方案B和C中，在不存在外部Ca 2+的情况下刺激细胞，随后在方案C中再施加外部Ca 2+。我们能够定量再现所有三个协议的重要功能，包括协议B的剂量反应，[Ca 2 +]i响应毒胡萝卜素，和滞后时间的结果，我们提供了定性的解释，从我们的计算得出的响应。我们还开发了一个简化的（封闭单元）版本的模型，其中PM通量被忽略，总游离钙离子浓度（[Ca 2 +]T）是一个缓慢变化的参数。这使我们能够解释在一个简单的图形方式PM流量可能会影响[Ca 2 +]i的反应，在RBH-2 H3细胞通过调制[Ca 2 +]T。
We undertake a quantitative investigation of changes in intracellular free Ca2+ concentration ([Ca2+]i) in antigen-stimulated rat basophilic leukemia (RBL-2H3) cells, which include contributions of both Ca2+ store release and Ca2+ influx from the medium. Following Keizer and De Young (J. Keizer and G. De Young. Biophys. J. 61: 649-660, 1992), we develop a highly constrained mathematical model for [Ca2+]i oscillations in RBL-2H3 cells, which includes activation of the inositol trisphosphate receptor (IP3R) by inositol 1,4,5-trisphospate, indirect Ca2+ activation of the IP3R via Ca2+ -dependent activity of phospholipase C-gamma, slow inhibition of the IP3R by cytosolic Ca2+, refilling of Ca2+ stores by a Ca2+ -ATPase (SERCA)-type pump, and a simple representation of the dependence of plasma membrane (PM) fluxes on experimental conditions. Using this full (open cell) model, we simulate [Ca2+]i responses for protocols in which antigen concentration and external Ca2+ are manipulated and compare out calculations with experimental data. In protocol A, cells are stimulated in the presence of external Ca2+, in protocols B and C, cells are stimulated in the absence of external Ca2+, with external Ca2+ later reapplied in protocol C. We are able to reproduce quantitatively the important features of all three protocols, including the dose response of protocol B, the [Ca2+]i response to thapsigargin, and lag time results, and we provide qualitative explanations for the responses derived from our calculations. We also develop a simplified (closed cell) version of the model in which PM fluxes are neglected and total free Ca2+ concentration ([Ca2+]T) is a slowly varying parameter. This permits us to explain in a simple graphical fashion how PM fluxes may influence [Ca2+]i responses in RBH-2H3 cells through modulation of [Ca2+]T.