IMPEDANCE SPECTROSCOPIC INVESTIGATION OF ION-CHANNEL FORMATION IN LIPID-MEMBRANES

Impedance spectra and capacity curves of lipid membranes modified with the ion channel peptide alamethicin exhibit characteristic shapes res ulting from interaction of the voltage sensitive channels with the per iodic voltage perturbation. To understand the interaction we calculate d the instationary behaviour using an 1-step model for the membrane ch annel formation. The model investigations show that the outer ac volta ge induces an ac channel current that compensates the membrane chargin g current yielding to curves similarly to the measured ones. The menti oned current compensation effect can be used for elucidating the kinet ics of ion channel formation.