title: Effects of double-layer polarization on ion transport.
abstract: It has been proposed that changes in ionic strength will alter the shape of current-voltage relations for ion transport across a lipid membrane. To investigate this effect, we measured currents across glyceryl monooleate membranes at applied potentials between 10 and 300 mV using either gramicidin and 1 mM NaCl or valinomycin and 1 mM KCl. A bridge circuit with an integrator as null detector was used to separate the capacitative and ionic components of the current. The changes in the current-voltage relations when ionic strength is varied between 1 and 100 mM are compared with predictions of Gouy-Chapman theory for the effects of these variations on polarization of the electrical diffuse double-layer. Double-layer polarization accounts adequately for the changes observed using membranes made permeable by either gramicidin or valinomycin.
mesh_terms: D001692:Biological Transport; D005989:Glycerides; D006096:Gramicidin; D007477:Ions; D008564:Membrane Potentials; D008567:Membranes, Artificial; D008954:Models, Biological; D009994:Osmolar Concentration; D011189:Potassium Chloride; D012965:Sodium Chloride; D014634:Valinomycin
chemical_list: D005989:Glycerides; D007477:Ions; D008567:Membranes, Artificial; D006096:Gramicidin; D014634:Valinomycin; D012965:Sodium Chloride; D011189:Potassium Chloride; C005953:monoolein