K. Yagisawa et al., A MODEL FOR SELF-SUSTAINED POTENTIAL OSCILLATION OF LIPID BILAYER-MEMBRANES INDUCED BY THE GEL LIQUID-CRYSTAL PHASE-TRANSITIONS, Biophysical journal, 64(5), 1993, pp. 1461-1475
To clarify the mechanism of self-sustained oscillation of the electric
potential between the two solutions divided by a lipid bilayer membra
ne, a microscopic model of the membrane system is presented. It is ass
umed, on the basis of the observed results (Yoshikawa, K., T. Omachi,
T. Ishii, Y. Kuroda, and K. liyama. 1985. Biochem. Biophys. Res. Commu
n. 133:740-744; Ishii, T., Y. Kuroda, T. Omochi, and K. Yoshikawa. 198
6. Langmuir. 2:319-321; Toko, K., N. Nagashima, S. liyama, K. Yamafuji
, and T. Kunitake. Chem. Lett. 1986:1375-1378), that the gel-liquid cr
ystal phase transition of the membrane drives the potential oscillatio
n. It is studied, by using the model, how and under what condition the
repetitive phase transition may occur and induce the potential oscill
ation. The transitions are driven by the repetitive adsorption and des
orption of proton by the membrane surface, actions that are induced by
the periodic reversal of the direction of protonic current. The essen
tial conditions for the periodic reversal are (a) at least one kind of
cations such as Na+ or K+ are included in the system except for proto
n, and the variation of their permeability across the membrane due to
the phase transition is noticeably larger than that of proton permeabi
lity; and (b) the phase transition has a hysteresis. When these condit
ions are fulfilled, the self-sustained potential oscillation may be br
ought about by adjusting temperature, pH, and the cation concentration
in the solutions on both sides of the membrane. Application of electr
ic current across the membrane also induces or modifies the potential
oscillation. Periodic, quasiperiodic, and chaotic oscillations appear
especially, depending on the value of frequency of the applied alterna
ting current.