Effects of nonequilibrium fluctuations on ionic transport through biomembranes

We investigate the effects of nonequilibrium flutuations on ionic transport through ion channels in membranes using the concept of localized ratchet. Due to the localization, the ionic population in the binding site can be en hanced or suppressed depending upon ionic potential and its fluctuations, a ffecting the gating kinetics of the channel. The localized dichotomic fluct uations of ionic potential are shown to give rise to a current reversal dif fering from the results of periodic ratchets. It is also found that strong correlations between binding energy and membrane potential fluctuations ind uce resonancelike behaviors in ionic current as the fluctuating rate varies . [S1063-651X(99)17010-7].