Single ionic channels induced in lipid bilayers by polyene antibiotics amphotericin B and nystatine

Abstract

AMPHOTERICIN B and nystatine increase the permeability of lipid membranes to ions, water and non-electrolytes^1,2. Cholesterol (or some other sterols) is a necessary membrane component for the antibiotics to be effective^1,3. Permeability to water and non-electrolytes increases linearly with ion permeability². The molecules of the size of glucose and larger are essentially impermeant. It is concluded^2,4 that amphotericin B and nystatine form aqueous pores with an effective radius of approximately 4 Å in thin lipid membranes. The changes in membrane conductance connected with the formation of a single pore have, however, not yet been observed. In this paper the properties of individual conductance channels induced in black lipid membranes by amphotericin B and nystatine are described briefly.