INVESTIGATIONS INTO THE MODEL FOR SELF-SUSTAINED POTENTIAL OSCILLATIONS IN LIPID BILAYERS BASED ON REPETITIVE PHASE-TRANSITIONS

The theoretical model for self sustained potential oscillation of lipi d bilayer membrane induced by gel-liquid crystal phase transitions, gi ven by Yagisawa et al. (Biophys. J. 64 (1993) 1461), has been experime ntally investigated using liquid membrane bilayer system. The data do not corroborate the postulate of gel-liquid crystal phase transition, induced by the repetitive adsorption and desorption of protons by the membrane surface. For example, in the proposed model no external stimu lus like externally applied electric current is necessary for the occu rrence of self sustained oscillations, whereas in the present experime nts no oscillations were observed unless an external current of magnit udes greater than or equal to 2.4 mA, with the compartment having high er H+ ion concentrations as negative was passed through the membrane. The model though theoretically self consistent does not seem to corres pond to the actual reality at least in the liquid membrane bilayer sys tem presently studied. (C) 1998 Elsevier Science B.V.