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钙依赖性钾通道在鼻咽癌细胞调节性容积回缩中起重要作用

和树同, 朱林燕, 杨林杰, 何斯纯, 毛建文, 王立伟, 陈丽新

暨南大学医学院1 生理学系； 药理学系, 广州 510632； 广东药学院生物学教研室，广州 510006

摘要

本研究采用膜片钳全细胞记录技术记录低渗诱发的人低分化鼻咽癌细胞(CNE-2Z)钾电流，用图像分析技术测量细胞容积，探讨不同类型K+ 通道在调节性容积回缩(regulatory volume decrease, RVD)中的作用。结果显示，细胞外灌流160mOsm/L 低渗液诱发CNE-2Z 细胞产生容积激活性钾电流和RVD，中等电导钙依赖性钾通道阻断剂clotrimazole (100 μmol/L)几乎完全抑制低渗诱发的钾电流和RVD。去除细胞外液的Ca2+ 后，低渗刺激不能诱发钾电流，RVD 显著减弱。电压依赖性钾通道阻断剂4-aminopyridine (4-AP, 5 mmol/L)部分抑制低渗诱发的钾电流。上述结果提示，钙依赖性钾通道是低分化鼻咽癌细胞容积激活性钾通道的主要类型；钙依赖性钾通道在鼻咽癌细胞RVD 中发挥了关键性作用，而电压依赖性钾通道在其中起部分作用。

关键词： 鼻咽肿瘤; 低渗溶液; 细胞大小; 钾离子通道

分类号：R739.63

[Ca2+-dependent potassium channels play important roles in regulatory volume decrease in human nasopharyngeal carcinoma cells.] [Ariticle in Chinese]

HE Shu-Tong, ZHU Lin-Yan, YANG Lin-Jie, HE Si-Chun, MAO Jian-Wen, WANG Li-Wei, CHEN Li-Xin

Department of Physiology； Department of Pharmacology, Medical College of Jinan University , Guangzhou 510632, China； Department of Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China

Abstract

It has been shown that cell volume regulation mechanisms play important roles in various cell functions. We demonstrated previously that volume-activated chloride channels were involved in cell volume regulation. The present study aimed to clarify the roles of various types of potassium channels in regulatory volume decrease (RVD) induced by hypotonic challenges in human nasopharyngeal carcinoma cells (CNE-2Z cells). The whole-cell patch clamp technique was used to record hypotonic challenge-induced potassium currents. During current recordings, cells were held at 0 mV and stepped to ±46 and ±92 mV, repeatedly. The cell volume was computed from cell diameters. The changes of cell volume were monitored and analyzed by the time-lapse imaging technique. The results showed that the exposure to 160 mOsm/L hypotonic solution caused the cells to swell by (144.5±4.2)%, activated a potassium current (59.2 pA/pF±13.3 pA/pF at 92 mV), and induced RVD. Cell volume was recovered from hypotonic challenge-induced swelling by (48.9±4.6)% after 20 min. The potassium current (at 92 mV) and RVD were inhibited by the calcium-dependent potassium channel blocker, clotrimazole (100 μmol/L), by (98.5±2.8)% and (89.3±4.9)%, respectively. Depletion of extracellular calcium prevented the activation of the hypotonic challenge-induced potassium current and inhibited the process of RVD. The voltage-gated potassium channel blocker, 4-AP (5 mmol/L), partially inhibited the hypotonic challenge-activated potassium currents by (66.6±5.3)% (at 92 mV). These results suggest that the Ca2+-dependent potassium channel is the main component of volume-activated potassium channels and plays an important role in volume regulation of CNE-2Z cells. The voltage-gated potassium channels may also contribute in part to the formation of the volume-activated potassium current.

Key words: nasopharyngeal neoplasms; hypotonic solutions; cell size; potassium channels

收稿日期：2009-06-29　　录用日期：2009-08-04

通讯作者：王立伟,陈丽新　　E-mail: wangliweic@sohu.com,

引用本文：

和树同, 朱林燕, 杨林杰, 何斯纯, 毛建文, 王立伟, 陈丽新. 钙依赖性钾通道在鼻咽癌细胞调节性容积回缩中起重要作用[J]. 生理学报 2009; 61 (5): 485-492.

HE Shu-Tong, ZHU Lin-Yan, YANG Lin-Jie, HE Si-Chun, MAO Jian-Wen, WANG Li-Wei, CHEN Li-Xin. [Ca2+-dependent potassium channels play important roles in regulatory volume decrease in human nasopharyngeal carcinoma cells.] [Ariticle in Chinese] . Acta Physiol Sin 2009; 61 (5): 485-492 (in Chinese with English abstract).