*Corresponding author. Tel: 00-44-29-20876670; Fax: 00-44-29-20874094; e-mail:
ChenL1@cardiff.ac.uk
中图分类号：Q25
人胎儿鼻咽上皮细胞的背景Cl-电流
孙雪荣1，王立伟1, 2，毛建文2，朱林燕3，聂思槐1，钟平1，陈丽新1, 2*
广东医学院1生理学研究室 、2细胞生物学研究室，湛江 524023；3中山大学医学院生理学教研室，广州 510000
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(160 mOsmol/L )则诱发细胞产生容积激活性氯电流。氯通道阻断剂tamoxifen和NPPB显著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份，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
Xue-Rong1, Wang Li-Wei1,2, Mao Jiang-Wen2,
Zhu Lin-Yan3, Nie Si-Huai1, Zhong Ping1,
Chen Li-Xin1, 2*
1 Laboratory of Physiology, 2Laboratory of Cell Biology, Guangdong Medical College, Zhanjiang 524023; 3Department of Physiology, Medical College, Sun Yat-Sen University, Guangzhou 510000
Abstract: To
characterize the background current in fetal human nasopharyngeal epithelial
cells and clarify its relationship with volume activated Cl- currents
(Icl,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- (-0.9mV). 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
µmol/L) and NPPB (100 µmol/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