中文摘要：

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（100μmol/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,5mmol/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。

英文摘要：

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 Ca^2＋-dependent potassium channel is the main component of volume-activated potassium channels and plays an important role in volume regulation of CNE-2Z ceils, The voltage-gated potassium channels may also contribute in part to the formation of the volume-activated potassium current.