Identification of a voltage-dependent anion channel in the apical membrane of a Cl(-)-secretory epithelium (MDCK).

An anion-selective channel of large unit conductance is present in apical membranes of a secretory epithelial cell. For cell-attached patch-clamp configuration on cultured MDCK cells channels with a conductance of about 460 pS are observed at 37 degrees C. The channel becomes spontaneously activated only in rare cases. In inside-out membrane patches the probability of observing this type of channel increased significantly suggesting that the channel is controlled by an up to now unknown mechanism. The channel shows a voltage-dependent burst kinetic.