Single channel K+ currents from HeLa cells.
The extracellular patch-clamp technique was used in order to investigate the presence of ionic channels in HeLa cells, a well-known cultured cell type obtained from an epidermoid carcinoma of the cervix. Under Gigohm-seal conditions, discrete current jumps could be observed with patch electrodes containing KCl. These channels were found to be mainly permeable to K+ and showed multiple levels of conductance. From single-channel I-V curve measurements, a strong rectification effect, characterized by a large inward and no detectable outward current, was observed. For negative membrane potentials (0 to -90 mV), the measured current-voltage relationship was found to be mostly linear, corresponding to a single-channel conductance of 40 pS. An analysis of some selected time records has revealed in addition that the probability of the channel to be in the open state was a function of the KCl concentration in the patch pipette.
D004553:Electric Conductivity; D006367:HeLa Cells; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D008564:Membrane Potentials; D011188:Potassium / Q000378:metabolism*; D011189:Potassium Chloride
D007473:Ion Channels; D011189:Potassium Chloride; D011188:Potassium