Electrical stability of artificial membranes.

The electrical breakdown potential of the planar lipid membranes has been shown to decrease following UV-induced lipid peroxidation, action of phospholipase A2, adsorption of protamine sulphate and expansion of the membrane by hydrostatic pressure. Membrane potential generated upon the addition of potassium acetate (or ammonium sulphate) and protonophore CCCP to liposomes, when large enough, was also able to break membranes; this was suggested by liposome swelling and a rapid decrease in suspension turbidity. UV-irradiation decreased liposomal membrane breakdown potential, while cholesterol increased it. Detergents and water-soluble products of lipid peroxidation decreased the breakdown potential. The possible role of the membrane electrical breakdown phenomenon in cell pathology is discussed.