| Abstract: | The cell-attached version of patch-clamp technique was used to search for calcium permeable channels in human carcinoma A-431 cells. With 100 mM CaCl2 in pipette, the inward currents were recorded having the mean unitary conductance of 2.8 pS and the reversal potential (obtained by linear extrapolation) equal to +25.5 mV. Application of the epidermal growth factor (EGF) into the bath extracellular solution produced a transient increase in probability for these channels to be open. The effect developed with a delay of about 20 seconds to last thereafter for 36 seconds (mean values). We propose that these channels mediate EGF-induced increase in concentration of cytosolic free calcium. |
