CALCIUM AND BARIUM PERMEATION THROUGH CALCIUM RELEASE-ACTIVATED CALCIUM (CRAC) CHANNELS
CALCIUM AND BARIUM PERMEATION THROUGH CALCIUM RELEASE-ACTIVATED CALCIUM (CRAC) CHANNELS
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DOI：
10.1007/bf00373905
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发表时间：
1995-07-01
影响因子：
4.5
通讯作者：
HOTH, M
中科院分区：
文献类型：
--
作者：
HOTH, M
最近已经在几种细胞类型中描述了由储存耗尽激活的Ca 2+电流，并且被称为I-CRAC（用于Ca 2+释放激活的Ca 2+电流）。本文研究了肥大细胞、大鼠嗜碱性白血病细胞（RBL）和人T淋巴细胞（Jurkat）中CRAC通道的Ca ~（2+）和Ba ~（2+）通透性。在所有三种细胞类型中，CRAC通道对Ca 2+超过一价阳离子的选择性是相同的，并且在测试的各种组织中至少与电压操作的Ca 2+（VOC）通道一样高。发现通过CRAC通道的Ba 2+电流相对于Ca 2+电流（I-Ba/l（Ca））的幅度强烈依赖于膜电位，并且与肥大细胞和RBL细胞相比，在Jurkat细胞中小得多。当使用不同的外部Ca 2+和Ba 2+的混合物时，在所有三种细胞类型的非常负的膜电位下观察到异常的摩尔分数行为。与VOC通道相反，在电位为正至-20 mV时未观察到异常摩尔分数效应。
A Ca2+ current activated by store depletion has been described recently in several cell types and has been termed I-CRAC (for Ca2+ release-activated Ca2+ current). In this paper, the Ca2+ and Ba2+ permeability of CRAC channels is investigated in mast cells, rat basophilic leukaemia cells (RBL) and human T-lymphocytes (Jurkat). The selectivity of CRAC channels for Ca2+ over monovalent cations is identical in all three cell types and is at least as high as that of voltage-operated Ca2+ (VOC) channels in the various tissues tested. The amplitude of Ba2+ currents relative to Ca2+ currents (I-Ba/l(Ca)) through CRAC channels was found to be strongly dependent on the membrane potential and was much smaller in Jurkat cells compared to mast and RBL cells. An anomalous mole-fraction behavior was observed at very negative membrane potentials in all three cell types when using different mixtures of external Ca2+ and Ba2+. In contrast to VOC channels, the anomalous mole-fraction effect was not observed at potentials positive to -20 mV.