TY - JOUR
T1 - Electrical characteristics in an excitable element of lipid membrane
AU - Toko, Kiyoshi
AU - Ozaki, Norimasa
AU - Iiyama, Satoru
AU - Yamafuji, Kaoru
AU - Matsui, Yoshiko
AU - Yamafuji, Keiko
AU - Saito, Minoru
AU - Kato, Masakazu
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1991/11
Y1 - 1991/11
N2 - Electrical characteristics in a membrane constructed from a porous filter adsorbed with a lipid analogue, dioleyl phosphate (DOPH), were investigated in a situation interposed between 100 mM NACl + 3 mM CaCl2 and 100 mM KCl. Calcium ions affected significantly the membrane characteristics. The membrane potential was negative on the KCl side, which implies the higher permeability to K+ than Na+; this tendency was increased by a tiny amount of Ca2+. While the membrane showed a low electrical resistance of several kΩ. cm2under K+/Na+ gradient, it showed several MΩ · cm2+ by Ca2+. The surface structure of the membrane exhibited many voids in the low-resistance state, but the surface was covered by oil droplets in the high-resistance state. Oscillations of the membrane potential appeared spontaneously with application of the electrical current from the KCl side to the NaCl + CaCl2 side. The frequency was increased with the electrical current. All these results were explained comprehensively using an electrochemical kinetic model taking account of the Ca2+ binding effect, where DOPH assemblies make a phase transition between oil droplets due to Ca2+ and multi-bilayers with excess K+. The oscillation arises from coupling of the phase transition to accumulation and release of K+ or Ca2+. This membrane can be used as an excitable element regulated by Ca2+ in neuro-computer devices.
AB - Electrical characteristics in a membrane constructed from a porous filter adsorbed with a lipid analogue, dioleyl phosphate (DOPH), were investigated in a situation interposed between 100 mM NACl + 3 mM CaCl2 and 100 mM KCl. Calcium ions affected significantly the membrane characteristics. The membrane potential was negative on the KCl side, which implies the higher permeability to K+ than Na+; this tendency was increased by a tiny amount of Ca2+. While the membrane showed a low electrical resistance of several kΩ. cm2under K+/Na+ gradient, it showed several MΩ · cm2+ by Ca2+. The surface structure of the membrane exhibited many voids in the low-resistance state, but the surface was covered by oil droplets in the high-resistance state. Oscillations of the membrane potential appeared spontaneously with application of the electrical current from the KCl side to the NaCl + CaCl2 side. The frequency was increased with the electrical current. All these results were explained comprehensively using an electrochemical kinetic model taking account of the Ca2+ binding effect, where DOPH assemblies make a phase transition between oil droplets due to Ca2+ and multi-bilayers with excess K+. The oscillation arises from coupling of the phase transition to accumulation and release of K+ or Ca2+. This membrane can be used as an excitable element regulated by Ca2+ in neuro-computer devices.
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U2 - 10.1016/0301-4622(91)80014-I
DO - 10.1016/0301-4622(91)80014-I
M3 - Article
C2 - 1773008
AN - SCOPUS:0026000816
VL - 41
SP - 143
EP - 156
JO - Biophysical Chemistry
JF - Biophysical Chemistry
SN - 0301-4622
IS - 2
ER -