title: On the ionic displacement current in lipid bilayer membranes.
abstract: It is shown that the constant field approximation must be amended to make it apply to time-dependent signals. The necessary additional term corresponds to the ionic displacement current. In the absence of adsorption, this ionic displacement current is found to have a characteristic time of the order of a fraction of a microsecond. We confirm its mathematical form as given by Cole (1965). When the membrane-soluble ions are strongly adsorbed, an additional, purely exponential transient of much larger time constant is calculated, with a time dependence identical to that of the translocation of adsorbed ions. Our results support the pseudostationary approximation used by Andersen and Fuchs (1975) in the description of such exponential transients. Explicit expressions are given for the current after a voltage step as for the admittance, both in the absence and presence of adsorption, for a membrane with a rectangular potential energy profile.
mesh_terms: D004553:Electric Conductivity; D007477:Ions; D008051:Lipid Bilayers; D008433:Mathematics; D008954:Models, Biological
chemical_list: D007477:Ions; D008051:Lipid Bilayers
references.citation: Physiol Rev. 1965 Apr;45:340-79
references.pmid: 14302913
references.citation: Proc Natl Acad Sci U S A. 1978 Apr;75(4):1612-5
references.pmid: 273894
references.citation: Biochim Biophys Acta. 1977 Feb 4;464(3):465-81
references.pmid: 836821
references.citation: Biochim Biophys Acta. 1973 May 25;307(3):429-43
references.pmid: 4718803
references.citation: J Gen Physiol. 1974 May;63(5):533-52
references.pmid: 4824995
references.citation: Nature. 1973 Apr 13;242(5398):459-61
references.pmid: 4700900
references.citation: Nature. 1973 May 25;243(5404):234-6
references.pmid: 4706296
references.citation: J Membr Biol. 1972;10(2):171-92
references.pmid: 4669446
references.citation: J Gen Physiol. 1976 Jun;67(6):749-71
references.pmid: 946975
references.citation: J Membr Biol. 1976 Jun 9;27(1-2):171-91
references.pmid: 933157
references.citation: J Membr Biol. 1975 Dec 4;25(1-2):93-114
references.pmid: 1214289
references.citation: Biophys J. 1975 Aug;15(8):795-830
references.pmid: 1148364
references.citation: J Membr Biol. 1975;22(2):125-41
references.pmid: 1170333
references.citation: J Theor Biol. 1969 Oct;25(1):113-26
references.pmid: 5349446
references.citation: Biophys J. 1969 Sep;9(9):1160-70
references.pmid: 5807223
references.citation: Nature. 1969 Mar 1;221(5183):844-6
references.pmid: 5765058