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人胎儿鼻咽上皮细胞的背景氯电流

孙雪荣, 王立伟, 毛建文, 朱林燕, 聂思槐, 钟平, 陈丽新

广东医学院生理学研究室. 广东, 湛江 524023；广东医学院细胞生物学研究室. 广东, 湛江 524023；中山大学医学院生理学教研室. 广东, 广州 510089

摘要

采用膜片钳和图像分析技术,研究人胎儿鼻咽上皮细胞背景电流的特性及其与容积激活性氯电流的关系.在等张溶液中,可记录到一背景电流,该电流呈微弱的外向整流性,无明显时间依赖性失活,其翻转电位为(-0.73±1.7)mV(n=21),接近氯离子平衡电位(-0.9 mV).细胞外高张刺激(440 mOsmol/L)明显抑制此电流(59.6±7.1)%,而低张刺激(160mOsmol/L)则诱发细胞产生容积激活性氯电流.氯通道阻断剂tamoxifen和5-硝基-2-(3-苯丙胺基)苯甲酸[5-nitro-2-(3-phenylpropylamino)benzoic acid,NPPB]显著地抑制背景电流并使细胞基础容积增大.上述结果表明,人胎儿鼻咽上皮细胞的背景Cl-电流是背景电流的重要成分,此Cl-电流与容积激活性氯电流及细胞基础容积调节有关。

关键词： 上皮细胞; 背景电流; 氯通道

Background chloride currents in fetal human nasopharyngeal epithelial cells

Sun Xuerong, Wang Liwei, Mao Jianwen, Zhu Linyan, Nie Sihuai, Zhong Ping, Chen Lixin

Laboratory of Physiology

Abstract

To characterize the background current in fetal human nasopharyngeal epithelial cells and clarify its relationship with volume activated Cl~(-) currents (I_(Cl, vol)), whole-cell patch clamp and cell imaging techniques were employed. Under isotonic conditions, a background current [(5.9±2.1) pA/pF at +80 mV, n=21] was detected. The current presented a weak outward rectification and a negligible time-dependent inactivation. The current-voltage relationship showed that the reversal potential of the background current [(–0.73±1.7) mV, n=21] was close to the calculated equilibrium potential for Cl~(–) (–0.9 mV). Application of extracellular hypertonic stimulation (440 mOsmol/L) suppressed the current by (59.6±7.1)% and the inhibition was reversible after returned to isotonic conditions. Bathing the cells in hypotonic solution (160 mOsmol/L) induced a volume-sensitive Cl~(–) current. The Cl~(–) channel blockers, tamoxifen (20 #mu#mol/L) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) (100 #mu#mol/L), inhibited the background current by (74.0±5.2)% (P<0.01, n=5) and (60.9±8.9)% (P<0.01, n=6) at +80 mV and increased basal cell volume by (107.7±2.9)% (P<0.01, n=25) and (104.4±2.4)% (P<0.01, n=19), respectively. The data indicate that Cl~(–) current is an important component of the background current in fetal human nasopharyngeal epithelial cells. The background Cl~(–) current is involved in volume activated Cl~(-) current and basal cell volume regulation.

Key words: Epithelial cells;Background currents;Chloride channels

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引用本文：

孙雪荣, 王立伟, 毛建文, 朱林燕, 聂思槐, 钟平, 陈丽新. 人胎儿鼻咽上皮细胞的背景氯电流[J]. 生理学报 2005; 57 (3): .

Sun Xuerong, Wang Liwei, Mao Jianwen, Zhu Linyan, Nie Sihuai, Zhong Ping, Chen Lixin. Background chloride currents in fetal human nasopharyngeal epithelial cells. Acta Physiol Sin 2005; 57 (3): (in Chinese with English abstract).