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Pflügers Archiv

, Volume 407, Issue 1, pp 59–63 | Cite as

New method for calculating pHi from accurately measured changes in pHi induced by a weak acid and base

  • M. S. Szatkowski
  • R. C. Thomas
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

Abstract

From the combined Henderson-Hasselbalch relations for a weak acid and a weak base, we derive an expression for steady-state intracellular pH(pHi). The derivation requires only accurate measurements of the pHi changes when the two electrolytes are applied, rather than absolute values. The method is based on the assumption of equilibrium of the neutral forms of the two compounds across the plasma membrane, that is, absence of permeation of the charged forms. It is also assumed that no significant pHi regulation takes place, that there is no significant permeability to intracellular buffers and that intracellular buffering power, over the measured span of pHi, is the same. This precludes the use of CO2/bicarbonate buffered systems. We find that under our experimental conditions steady-state pHi values calculated in this way agree closely with those measured directly with pH-sensitive microelectrodes both in snail neurones and crab muscle. The method would allow the intracellular calibration of other pHi measuring techniques.

Key words

Intracellular pH Weak acid and base Buffering power 

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References

  1. Adrian RH (1956) The effect of internal and external potassium concentration on the membrane potential of frog muscle. J Physiol 133:631–658Google Scholar
  2. Aickin CC, Thomas RC (1975) Micro-electrode measurement of the internal pH of crab muscle fibres. J Physiol 252:803–815Google Scholar
  3. Ammann D, Lanter F, Steiner RA, Schulthess P, Shijo Y, Simon W (1981) Neutral carrier based hydrogen ion selective microelectrode for extra- and intracellular studies. Anal Chem 53:2267–2269Google Scholar
  4. Boron WF, Roos A (1976) Comparison of microelectrode, DMO, and methylamine methods for measuring intracellular pH. Am J Physiol 231:799–809Google Scholar
  5. Pressman BC (1976) Biological applications of ionophores. Annu Rev Biochem 45:501–530Google Scholar
  6. Roos A, Boron WF (1981) Intracellular pH. Physiol Rev 61:296–434Google Scholar
  7. Sharp A, Thomas RC (1981) The effects of chloride substitution on intracellular pH in crab muscle. J Physiol 312:71–80Google Scholar
  8. Szatkowski MS, Thomas RC (1986) Calculations of steady-state pHi from pHi changes caused by weak acids and bases in snail neurones. J Physiol 371:153PGoogle Scholar
  9. Thomas RC (1974) Intracellular pH of snail neurons measured with a new pH-sensitive glas micro-electrode. J Physiol 238:159–180Google Scholar
  10. Thomas RC (1978) Ion-sensitive intracellular microelectrodes: how to make and use them. London: Academic PressGoogle Scholar
  11. Thomas RC (1982) Snail neuron intracellular pH regulation. In: Nuccitelli R, Deamer DW (eds) Intracellular pH: its measurement, regulation and utilization in cellular functions. Liss, New York, pp 189–204Google Scholar
  12. Thomas RC (1984) Experimental displacement of intracellular pH and the mechanism of its subsequent recovery. J Physiol 354:3P-22PGoogle Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • M. S. Szatkowski
    • 1
  • R. C. Thomas
    • 1
  1. 1.Department of Physiology, The Medical SchoolUniversity of BristolBristolUK

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