Ca(2+)-dependent potassium channels play important roles in regulatory volume decrease in human nasopharyngeal carcinoma cells

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 sw