OSMOTIC SWELLING ACTIVATES INTERMEDIATE-CONDUCTANCE CL- CHANNELS IN HUMAN INTESTINAL EPITHELIAL-CELLS

During osmotic swelling of a human intestinal epithelial cell line, st epwise closing unitary events of Cl- channels could be observed in cel l-attached patches upon application of large positive potentials only when inactivating whole-cell Cl- currents were simultaneously observed . The closing process became faster with increasing positive command p ulses. The unitary conductance was around 32 pS at 60 mV, 37 pS at + 1 00 mV, and 47 pS at + 140 mV exhibiting outward rectification.