Liposome mediated dissipation of valinomycin-imposed potassium potential across erythrocytes membrane.
Influence of liposomes made of phosphatidylcholine (PC) on the valinomycin-imposed potassium potential across erythrocyte membrane was examined by measuring the fluorescence change of the potential-sensitive cyanine dye. We concluded that the liposomes modulate ion selectivity of the membrane embedded valinomycin, on the basis of the following lines of evidence. (i) The valinomycin-imposed potassium potential across erythrocyte membrane (interior negative) was dissipated in the presence of PC-liposomes. (ii) When PC-liposomes were added to the cell suspension before the valinomycin, a membrane potential could not be imposed. (iii) Liposomes containing only the PC of saturated fatty acids were inactive in the potential dissipation, whereas the liposomes containing PC of unsaturated fatty acids were fully active. (iv) Liposome-mediated dissipation of the imposed-membrane potential was similarly observed in the resealed erythrocyte ghosts. (v) The liposomes did not show a detectable effect on the gramicidin-mediated proton potential. (vi) The effect of liposome was somewhat analogous to the nigericin-mediated dissipation of the valinomycin-imposed potassium potential.
D000818:Animals; D004910:Erythrocyte Membrane / Q000187:drug effects*; D005071:Evoked Potentials / Q000187:drug effects; D006736:Horses; D008081:Liposomes / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D013696:Temperature; D014634:Valinomycin / Q000008:administration & dosage* / Q000494:pharmacology
D008081:Liposomes; D014634:Valinomycin; D011188:Potassium