The effect of amphotericin B on the K-channel activity of MDCK cells.
By using the whole-cell patch technique, it is shown that the total outward current is increased, as a function of time, after the addition of amphotericin B to the bathing solution. The whole-cell current is shown to be primarily a K-channel current by the blockage of this current upon application of TEA to the bathing solution. Single K-channel studies, using the outside-out patch-clamp technique, reveal that the single K-channel opening probability increases by a factor of six after the addition of amphotericin B. In addition, single K-channel voltage dependent studies, using the inside-out patch-clamp technique, demonstrate that this increase in opening probability is due to an increase in the amplitude of Po(v). In contrast to the present belief that amphotericin B simply creates pores in a cell's membrane, these results suggest that amphotericin B can also influence the function of the cell's K-channel proteins.
School of Pharmacy, University of Wisconsin, Madison 53706.
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Hsu
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Burnette
D000666:Amphotericin B / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004285:Dogs; D008564:Membrane Potentials; D015221:Potassium Channels / Q000187:drug effects*; D011487:Protein Conformation
D015221:Potassium Channels; D000666:Amphotericin B