Analytical steady-state solution to the rapid buffering approximation near an open Ca2+ channel
Analytical steady-state solution to the rapid buffering approximation near an open Ca2+ channel
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DOI：
10.1016/s0006-3495(96)79500-0
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发表时间：
1996-12-01
影响因子：
3.4
通讯作者：
Smith, GD
中科院分区：
文献类型：
--
作者：
Smith, GD
我们推导了一个基于传输方程的开放Ca2+通道附近Ca2+分布的解析稳态解，该方程描述了在快速静止和移动的Ca2+缓冲区存在下Ca2+的缓冲扩散（瓦格纳和Keizer，1994）。这种稳定状态的快速缓冲近似给出了一个上限的本地Ca2+海拔高度，如Ca2+泡芙或火花时，快速缓冲近似的有效性条件得到满足，是一种替代近似，假设移动的缓冲区是不饱和的。该结果还提供了通道孔附近细胞溶质Ca2+结构域浓度（[Ca2+]（d））的分析估计值，并显示了[Ca2+]（d）对中等浓度的内源性移动的缓冲液、Ca2+指示剂染料和大量细胞溶质Ca2+的依赖性。假设[Ca2+]（d）和细胞内Ca2+通道的内腔耗竭结构域之间存在简单关系，内腔和胞质Ca2+曲线匹配，以给出大量内腔Ca2+对[Ca2+]（d）影响的隐式分析表达式。
We derive an analytical steady-state solution for the Ca2+ profile near an open Ca2+ channel based on a transport equation which describes the buffered diffusion of Ca2+ in the presence of rapid stationery and mobile Ca2+ buffers (Wagner and Keizer, 1994). This steady-state rapid buffering approximation gives an upper bound on local Ca2+ elevations such as Ca2+ puffs or sparks when conditions for the validity of the rapid buffering approximation are met and is an alternative to approximations that assume that mobile buffers are unsaturable. This result also provides an analytical estimate of the cytosolic Ca2+ domain concentration ([Ca2+](d)) near a channel pore and shows the dependence of [Ca2+](d) on moderate concentrations of endogenous mobile buffer, Ca2+ indicator dye, and bulk cytosolic Ca2+. Assuming a simple relationship between [Ca2+](d) and the lumenal depletion domain of an intracellular Ca2+ channel, lumenal and cytosolic Ca2+ profiles are matched to give an implicit analytical expression for the effect of bulk lumenal Ca2+ on [Ca2+](d).