A quantitative assessment of the use of 36Cl- distribution to measure plasma membrane potential in isolated hepatocytes.
The plasma membrane potential of isolated rat hepatocytes was clamped at different values between 0 and -68 mV by addition of valinomycin in the presence of different extracellular concentrations of K+, and measured by the distribution of 86Rb+ between cells and medium. 36Cl- distribution came to steady state in 10-15 min. This steady-state distribution was compared to the plasma membrane potential over a range of values. 36Cl- distribution provided an accurate measurement of plasma membrane potential between -4 and -40 mV. At higher potentials intracellular chloride concentration is less than 20% of the extracellular concentration and errors due to uncertainties in the measurement of intracellular volume and of the contamination of cell pellets by extracellular medium precluded accurate determination of membrane potential: thus in our experiments 36Cl- underestimated the plasma membrane potential at -68 mV by 8 mV.
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Department of Biochemistry, University of Cambridge, U.K.
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism*; D002713:Chlorine; D005260:Female; D007202:Indicators and Reagents; D007700:Kinetics; D008099:Liver / Q000502:physiology*; D008564:Membrane Potentials; D009861:Onium Compounds / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D011868:Radioisotopes; D051381:Rats; D011919:Rats, Inbred Strains; D012235:Rhodamines; D012414:Rubidium Radioisotopes / Q000378:metabolism; D013194:Staining and Labeling; D014320:Triphenylmethyl Compounds / Q000378:metabolism; D014343:Trypan Blue; D014634:Valinomycin / Q000494:pharmacology
D002712:Chlorides; D007202:Indicators and Reagents; D009861:Onium Compounds; D011868:Radioisotopes; D012235:Rhodamines; D012414:Rubidium Radioisotopes; D014320:Triphenylmethyl Compounds; C026188:rhodamine 6G; C011561:triphenylmethylphosphonium; D014634:Valinomycin; D002713:Chlorine; D000255:Adenosine Triphosphate; D014343:Trypan Blue; D011188:Potassium