A SINGLE-POOL MODEL FOR INTRACELLULAR CALCIUM OSCILLATIONS AND WAVES IN THE XENOPUS-LAEVIS OOCYTE
A SINGLE-POOL MODEL FOR INTRACELLULAR CALCIUM OSCILLATIONS AND WAVES IN THE XENOPUS-LAEVIS OOCYTE
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DOI：
10.1016/s0006-3495(93)81191-3
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发表时间：
1993-10-01
影响因子：
3.4
通讯作者：
SNEYD, J
中科院分区：
文献类型：
--
作者：
ATRI, A;AMUNDSON, J;SNEYD, J
我们构建了一个基于Ca2+通过单个细胞内Ca2+池的肌醇1,4,5-三磷酸（IP3）受体/Ca2+通道（IP3R）释放的胞质游离Ca2+振荡的最小模型。该模型依赖于实验证据，即胞质游离钙浓度（[Ca2+]c）以双相方式调节IP3R，低和高[Ca2+]c抑制Ca2+释放，中间[Ca2+]c促进Ca2+释放，通道失活发生的时间尺度比激活慢。该模型在恒定的[IP3]下产生[Ca2+]c振荡，并重现了一些关键的实验。在IP3动力学、IP3胞质扩散（D(p) = 300 mum2 s-1）和Ca2+胞质扩散（D(c) = 20 mum2 s-1）的二维空间模型中，Ca2+以7-15 mum的速度产生圆形、平面和螺旋波。S-1，碰撞后湮灭。增加细胞外[Ca2+]内流增加波速和基线[Ca2+]c。A [Ca2+]c依赖的Ca2+扩散系数不改变模型的定性行为。一个重要的模型预测是，为了使波传播，通道失活必须在比激活更慢的时间尺度上发生。该模型用于捕获在非洲爪蟾卵母细胞中参与细胞内Ca2+振荡和行波产生的基本宏观机制。
We construct a minimal model of cytosolic free Ca2+ oscillations based on Ca2+ release via the inositol 1,4,5-trisphosphate (IP3) receptor/Ca2+ channel (IP3R) of a single intracellular Ca2+ pool. The model relies on experimental evidence that the cytosolic free calcium concentration ([Ca2+]c) modulates the IP3R in a biphasic manner, with Ca2+ release inhibited by low and high [Ca2+]c and facilitated by intermediate [Ca2+]c, and that channel inactivation occurs on a slower time scale than activation. The model produces [Ca2+]c oscillations at constant [IP3] and reproduces a number of crucial experiments. The two-dimensional spatial model with IP3 dynamics, cytosolic diffusion of IP3 (D(p) = 300 mum2 s-1), and cytosolic diffusion of Ca2+ (D(c) = 20 mum2 s-1) produces circular, planar, and spiral waves of Ca2+ with speeds of 7-15 mum.s-1, which annihilate upon collision. Increasing extracellular [Ca2+] influx increases wave speed and baseline [Ca2+]c. A [Ca2+]c-dependent Ca2+ diffusion coefficient does not alter the qualitative behavior of the model. An important model prediction is that channel inactivation must occur on a slower time scale than activation in order for waves to propagate. The model serves to capture the essential macroscopic mechanisms that are involved in the production of intracellular Ca2+ oscillations and traveling waves in the Xenopus laevis oocyte.