Shoemaker Patrick A, Bekkouche Bo M B
Computational Science Research Center, San Diego State University, San Diego, CA, USA.
, Nevrobo AB (5593306664), Stockholm, Sweden.
J Comput Neurosci. 2025 Apr 2. doi: 10.1007/s10827-025-00898-2.
We report a parametric simulation study of traveling calcium waves in two classes of cellular structures: dendrite-like processes and an idealized cell body. It is motivated by the hypothesis that calcium waves may participate in spatiotemporal sensory processing; accordingly, its objective is to elucidate the dependence of traveling wave characteristics (e.g., propagation speed and amplitude) on various anatomical and physiological parameters. The models include representations of inositol trisphosphate and ryanodine receptors (which mediate transient calcium entry into the cytoplasm from the endoplasmic reticulum), as well as other entities involved in calcium transport or reactions. These support traveling cytoplasmic calcium waves, which are fully regenerative for significant ranges of model parameters. We also observe Hopf bifurcations between stable and unstable regimes, the latter being characterized by periodic calcium spikes. Traveling waves are possible in unstable processes during phases with sufficiently high calcium levels in the endoplasmic reticulum. Damped and abortive waves are observed for some parameter values. When both receptor types are present and functional, we find wave speeds on the order of 100 to several hundred micrometers per second and cytosolic calcium transients with amplitudes of tens of micromolar; when ryanodine receptors are absent, these values are on the order of tens of micrometers per second and 1-6 micromolar. Even with significantly downgraded channel conductance, ryanodine receptors can significantly impact wave speeds and amplitudes. Receptor areal densities and the diffusion coefficient for cytoplasmic calcium are the parameters to which wave characteristics are most sensitive.
树突状突起和理想化的细胞体。该研究的动机是基于钙波可能参与时空感觉处理的假设；因此，其目的是阐明行波特征（如传播速度和振幅）对各种解剖学和生理学参数的依赖性。这些模型包括肌醇三磷酸和兰尼碱受体（介导钙从内质网瞬时进入细胞质）的表征，以及参与钙运输或反应的其他实体。这些支持细胞质钙波的传播，对于显著范围的模型参数，这些钙波是完全再生的。我们还观察到稳定和不稳定状态之间的霍普夫分岔，后者的特征是周期性钙尖峰。在内质网钙水平足够高的阶段，不稳定过程中可能会出现行波。对于某些参数值，观察到了衰减波和夭折波。当两种受体类型都存在且起作用时，我们发现波速在每秒100到几百微米的量级，胞质钙瞬变幅度为几十微摩尔；当没有兰尼碱受体时，这些值在每秒几十微米和1 - 6微摩尔的量级。即使通道电导显著降低，兰尼碱受体也能显著影响波速和振幅。受体面密度和细胞质钙的扩散系数是波特征最敏感的参数。
