Discreteness of Conductance Change in Bimolecular Lipid Membranes in the Presence of Certain Antibiotics

Abstract

NET ion movements across biological or synthetic lipid membranes may take place by various mechanisms, underlying all of which there is a rather ill-defined and small ion leakage or background conductance. Most ions permeate by means of pathways involving either permanent or transient modifications of the basic structure of the membrane. If permanent pathways are involved, a given membrane conductance may be accounted for by routes which are either numerous and of low conductance or few and of high conductance. For transient pathways, duration must also be considered. Thus, if a carrier is invoked, the duration will be the time the carrier, complexed with an ion, spends shuttling across the membrane. For a pore, the duration is the time for which it remains open to ions. At present little is known concerning the number, conductance and duration of the ionic pathways in any membrane of the types mentioned. Limited information is available for the nerve membrane, although this is rather imprecise and indirect¹.