[Effect of amphotericin B added to one side of a membrane]

Amphotericin B which was added to the one side of a membrane in aqueous solutions with low pH 3.0 sharply increases the membrane conductance by the mechanism of channel forming. Long living ionic channels (20 sec) with large conductance dispersion (2-20 Ps) were found at the concentration 2 X 10(-8) M. Amphotericin B concentration which is necessary for obtaining single channels does not depend on cholesterol concentration in the membrane-forming solution in the range from 2 to 10 mg/ml. The effect of amphotericin B on the membrane depends on the phospholipid concentration in the membrane. The one-side selective permeability is the same as one under the symmetric action of the antibiotic. It is assumed that amphotericin B induced the membrane conductance by the mechanism of half-pores formation.