CALCIUM CURRENTS RECORDED FROM A NEURONAL ALPHA(1C) L-TYPE CALCIUM-CHANNEL IN XENOPUS-OOCYTES
CALCIUM CURRENTS RECORDED FROM A NEURONAL ALPHA(1C) L-TYPE CALCIUM-CHANNEL IN XENOPUS-OOCYTES
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DOI：
10.1016/0014-5793(94)00357-2
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发表时间：
1994-05-09
期刊：
影响因子：
3.5
通讯作者：
NARGEOT, J
中科院分区：
文献类型：
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作者：
CHARNET, P;BOURINET, E;NARGEOT, J
本研究以表达神经元α(1C)、α(2)和β(1b)钙通道亚单位的非洲爪哇卵母细胞为研究对象。在双电压钳记录过程中，向卵母细胞注入10~20nL的100 mM BAPTA溶液。在此条件下，内源性钙激活的氯电流被完全抑制，从而产生无氯电流污染的α(1C)Ba电流。BAPTA注射还允许检测具有不同渗透离子(包括钙)的α(1C)电流。与Ba型和Sr型钙电流相比，α(1C)型全细胞钙电流的幅度更小，其动力学和电压依赖性更接近于在自然细胞中记录到的L型钙电流。在BAPTA缓冲的细胞中发生的钙依赖失活表明，这种类型的失活涉及的钙结合部位非常接近通道的孔洞。
Xenopus oocytes expressing neuronal alpha(1C), alpha(2) and beta(1b) calcium channel subunit cDNAs were used in this study. During two-electric voltage clamp recording the oocyte was injected with 10-20 nl of a 100 mM BAPTA solution. Under these conditions, the endogenous Ca-activated Cl current was completely suppressed resulting in an alpha(1C) Ba current free from Cl current contamination. BAPTA injection also allowed alpha(1C) currents with different permeating ions, including Ca, to be examined. Compared to Ba and Sr, alpha(1C) whole cell Ca currents were smaller in magnitude and showed kinetic and voltage-dependent properties more similar to those for L-type Ca currents recorded in native cells. That Ca-dependent inactivation occurs in BAPTA-buffered cells suggests that the Ca-binding site involved in this type of inactivation is very close to the pore of the channel.