Ion-sensitive microelectrode measurements of free intracellular chloride and potassium concentrations in hyperthermia-treated neuroblastoma cells.
Murine NG108-15 neuroblastoma cells were heated for times of 5-40 min at 45.5 degrees C, and survival ranged from 0.7-0.0015, respectively. Ion-sensitive microelectrodes (ISM) were used to measure the free intracellular concentrations of Cl- and K+ immediately after heating and up to 30 hr later. The free intracellular Cl- and K+ concentrations, [Cl-]i and [K+]i respectively, of the heated cells remained identical to those of the controls for the first 10 hr after heating. At later times, some cells had increased [Cl-]i values and decreased [K+]i values identical to those of the extracellular medium. These cells had a mottled morphology, no longer excluded the vital stain trypan blue, and had no membrane potential. The number of these dye-including, physiologically dead cells increased with time, and was always greater following longer heating times. No changes in mean cellular volume were observed until 25 hr after heating. All trypan-blue-excluding, physiologically live cells had the same [Cl-]i and [K+]i as the control cells, even when the majority of them were destined for clonogenic death.
D000818:Animals; D001826:Body Fluids / Q000032:analysis*; D002460:Cell Line; D002470:Cell Survival; D002712:Chlorides / Q000032:analysis*; D006358:Hot Temperature; D007424:Intracellular Fluid / Q000032:analysis*; D008564:Membrane Potentials; D051379:Mice; D008839:Microelectrodes; D008858:Microscopy, Phase-Contrast; D009447:Neuroblastoma / Q000032:analysis*; D011188:Potassium / Q000032:analysis*; D013997:Time Factors
D002712:Chlorides; D011188:Potassium