Voltage-gated Ca2+ currents in rat gastric enterochromaffin-like cells
Voltage-gated Ca2+ currents in rat gastric enterochromaffin-like cells
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DOI：
10.1152/ajpcell.1998.274.2.c424
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发表时间：
1998-02-01
影响因子：
5.5
通讯作者：
Prinz, C
中科院分区：
文献类型：
--
作者：
Bufler, J;Choi, GC;Prinz, C
肠染色质样细胞（ECL）是胃粘膜中含有组胺的内分泌细胞，其维持负膜电位约为-50 mV，主要是由于电压门控K+电流[D]。厕所。G. Sachs和C. Print。Atn。[j].中国生物医学工程学报，2016,31(2):379 - 379。目前的研究调查了单个ECL细胞中电压门控Ca2+通道的存在。从大鼠基底粘膜中分离ECL细胞，经洗脱、密度梯度离心、原代培养，纯度为bb0 ~ 90%。电压门控Ca2+电流在单个ECL细胞中使用膜片钳技术的全细胞结构进行测量。在Na+或K+阻断溶液存在和添加20 mM细胞外Ca2+的情况下记录去极化激活电流。ECL细胞在测试电位为-20 mV时显示出向内电流，在+20 mV和20 mM细胞外Ca2+时观察到最大向内电流。随着负保持电位的增加，电流的失活率降低，在-30 mV保持电位下完全消失，细胞外添加20 mM Ba2+而不是20 mM Ca2+增加了去极化诱导电流，降低了失活率。向内电流被特异性l型Ca2+通道抑制剂维拉帕米（0.2 mM）完全抑制，被l型Ca2+通道激活剂BAY K 8644 （0.07 mM）增强。我们得出结论，去极化激活了ECL细胞中高压激活的Ca2-通道。激活特性、Ba2+效应和药理学结果表明存在l型Ca2+通道，而失活动力学表明大鼠胃ECL细胞存在额外的n型通道。
Enterochromaffin-like (ECL) cells are histamine-containing endocrine cells in the gastric mucosa that maintain a negative membrane potential of about -50 mV, largely due to voltage-gated K+ currents [D. F. Loo. G. Sachs, and C. Print. Atn. J. Physiol. 270 (Gastrointest Liver Physiol. 33): G739-G745, 1996]. The current study investigated the presence of voltage-gated Ca2+ channels in single ECL cells. ECL cells mere isolated from rat fundic mucosa by elutriation, density gradient centrifugation, and primary culture to a purity >90%. Voltage-gated Ca2+ currents were measured in single ECL cells using the whole cell configuration of the patch-clamp technique. Depolarization-activated currents were recorded in the presence of Na+ or K+ blocking solutions and addition of 20 mM extracellular Ca2+. ECL cells showed inward currents in response to voltage steps that were activated at a test potential of around -20 mV with maximal inward currents observed at +20 mV and 20 mM extracellular Ca2+. The inactivation rate of the current decreased with increasingly negative holding potentials and was totally abolished at a holding potential of -30 mV, Addition of extracellular 20 mM Ba2+ instead of 20 mM Ca2+ increased the depolarization-induced current and decreased the inactivation rate. The inward current was fully inhibited by the specific L-type Ca2+ channel inhibitor verapamil (0.2 mM) and was augmented by the L-type Ca2+ channel activator BAY K 8644 (0.07 mM). We conclude that depolarization activates high-voltage-activated Ca2- channels in ECL cells. Activation characteristics, Ba2+ effects, and pharmacological results imply the presence of L-type Ca2+ channels, whereas inactivation kinetics suggest the presence of additional N-type channels in rat gastric ECL cells.