SINGLE-CHANNEL RECORDINGS OF VOLUME-SENSITIVE CL- CHANNELS IN HUMAN INTESTINAL EPITHELIAL-CELLS

Under the double-patch configuration, stepwise closing unitary events could be observed in the on-cell patch upon applications of large posi tive potentials only when inactivating whole-cell Cl- currents were si multaneously observed in cultured human epithelial cells (Intestine 40 7) after osmotic swelling. Under the cell-attached configuration, the single channel events exhibited similar time- and voltage-dependent in activation upon large depolarizations. The inactivation time course be came shorter with increasing positive command pulses. The unitary slop e conductance was around 63 pS at + 140 mV and 46 pS at + 100 mV exhib iting outward rectification.