Comparative measurements of potassium and chloride with ion-sensitive microelectrodes and x-ray microanalysis in cultured skeletal muscle fibers

Abstract

Data of the intracellular electrolyte concentration of potassium and chloride in cultured muscle cells measured by x-ray analysis were compared by using the different activity coefficients with intracellular potassium and chloride activities measured with double-barrelled microelectrodes. By using an activity coefficient of 0.6, 95% of the potassium microelectrode measurements are in accordance with the x-ray analysis values, in spite of a scattering of the values. Membrane potential and intracellular potassium values are linearly related. x-ray analysis and ion-sensitive microelectrodes measured the cytoplasmic chloride in the same range. Taking into account known activity coefficients, an error of 25% must be assumed with the intracellular chloride measurements. However, x-ray analysis and ion-sensitive microelectrode investigations are reliable tools to study intracellular potassium and chloride changes, which play an important role in membrane characteristics.

The Na+,K+,2Cl−‐cotransport system in HeLa cells: Aspects of its physiological regulation

“…crKi = 0.9, aNai = 0.2, and aCli = 0.7 represent factors correcting for the respective ion activities in the cytoplasm. aKi, aNai, and aCli are estimated, based on the literature (Pietrzyk and Heinz, 1974;Acker et al, 1985;Liu et al, 1987). At extracellular concentrations of [K+l, = 5 mM, "a+], = 148 mM, and [Cl-I, = 141 mM in PBS, 37"C, and intracellular concentrations of [K+li = 149 mM, [Na+li = 44 mM and [Cl-li = 45 mM in HeLa cells (see Materials and Methods), the net driving force (Ap& for Na+,K+,2Cl--cotransport becomes 6.54 kJlMol when the above values are substituted into the above equation.…”

“…from duplicate dishes of six separate experiments). For calculations of the driving force of Na+,K+,2Clp-cotransport overall intracellular concentrations of Na+, K+, and C1-were corrected for cytoplasmic ion activities according to the findings of others (Pietrzyk and Heinz, 1974;Acker et al, 1985;Liu et al, 1987). The following activities for Na+, K+, and C1-in the cytoplasm were estimated: aNai = 9 mM, aKi = 134 mM, and aCli = 31.5 mM.…”

X‐ray microanalysis of freeze‐dried and frozen‐hydrated cryosections

“…The compartments where the spectra were obtained are indicated. tential and the intracellular ion concentrations (low sodium, high potassium) were found to be the most sensitive viability criteria for various mammalian cells (Abraham et al, 1985;Acker et al, 1985;Bauer et al, 1975;Kinne, 1983;LeFurgey et al, 1986). High calcium concentrations in the mitochondria and to a lesser extent in the cytoplasm were also reported for many kinds of cell injury (see Buja et al, 1985;LeFurgey et al, 1986;Osornio-Vargas et al, 1981).…”

Controlled Release of Biologically Active Silver from Nanosilver Surfaces

“…The red dashed curve gives total dissolved silver (Ag dis ), which passes through a minimum at 3 mM Cl − . Gray dashed lines give typical chloride concentrations in environmental and biological scenarios: (a) groundwater;27 (b) surface freshwater;28 (c) mitochondria;29 (d) cytoplasm;29 (e) extracellular spaces; and (f) seawater. The shaded square gives typical total silver and chloride concentrations used in example biological studies on: (1) nitrifying bacteria;30 (2) E. coli ;16 (3) primary human skin fibroblasts;31 (4) keratinocytes;32 (5) methicillin-resistant Staphylococcus aureus 33.…”