Ion Concentration Ratios, Calculated Equilibrium Potentials, and Measured Transmembrane Potentials

Range Table - link
Organism Various
Reference Stein, Wilfred D., Litman, Thomas, Channels, carriers and pumps An introduction to Membrane Transport, 2nd edition, 2015, Academic press inc. Harcourt Brace Jovanovich, Publishers p.49 table 2.2
Primary Source See primary refs beneath table
Method Calculated from equation 2.6 Membrane potential=2.303×RTlog[SII/SI]/(ZF) where R is gas constant, T temperature in degree Kelvin, Z number of units of valence per ion, F Faraday constant, SI and SII concentrations on one side and on second side of membrane. R and F expressed in caloric units rather than joules
Comments P.48 4th paragraph: "Table 2.2 lists ion concentrations and transmembrane potentials for a variety of cell types." P.49 bottom paragraph: "In many animal cells, the chloride and potassium ions have such oppositely poised concentration ratios [with potassium high and chloride low, intracellularly (see Table 2.2)], both ions often being not far from equilibrium with the electrical potential across the membrane. If the concentration gradient for S is not that given by Eq. (2.5), the system has the capacity to perform work, which it will do if the means of doing so are provided." Table gives ion concentrations, calculated equilibrium potential and measured transmembrane potential, including chick embryo heart muscle cells Δѱ=-70 (primary source Wheeler et al., 1982 PMID 7114248). Range of potentials: from Δѱ=-10mV to -14mV (human Red Blood Cell) to Δѱ=-138 Algal cell (Nitella). See BNID 103386, 103389, 102120
Entered by Uri M
ID 104083