Pflügers Archiv

, Volume 349, Issue 4, pp 285–294 | Cite as

Intracellular bicarbonate in single skeletal muscle fibers

  • R. N. Khuri
  • K. K. Bogharian
  • S. K. Agulian


This is the first direct potentiometric determination of intracellular bicarbonate concentration. The new method involves the use of a double-barrelled HCO3-selective liquid ion-exchange microelectrode that permits the simultaneous determination of intracellular [HCO3] and membrane PD of single cells. The mean in situ intracellular [HCO3] of single striated muscle fibers was 4.4±0.3 mM/l in the frog and 12.6±0.6 mM in the rat. Both values are inconsistent with a Donnan equilibrium distribution and can be accounted for by an active HCO3 influx or an active H+ efflux. During progressive acute hypercapnia there is an accumulative build-up of intracellular bicarbonate in rat skeletal muscle. The increase in intracellular [HCO3] with hypercapnia is strictly proportional to the associated increase in plasma [HCO3], thus maintaining a constant ratio of extracellular: intracellular [HCO3]. Using the directly measured [HCO3] in cell water, we calculate a cell pH of 7.00 for frog fibers and of 7.14 for rat fibers, both values being about 1.1 pH units on the alkaline side of those predicted for a Donnan equilibrium distribution of H+ ions across the cell membrane.

Key words

Bicarbonate Microelectrode Intracellular Bicarbonate Cell Bicarbonate Muscle Cell Bicarbonate Cell pH 


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  1. 1.
    Adrian, R. H.: The effect of internal and external potassium concentration on the membrane potential of frog muscle. J. Physiol. (Lond.)133, 631–658 (1956)Google Scholar
  2. 2.
    Burnell, J. M.: In vivo response of muscle to changes in CO2 tension or extracellular bicarbonate. Amer. J. Physiol.215, 1376–1383 (1968)Google Scholar
  3. 3.
    Butler, T. C., Poole, D. T., Waddell, W. J.: Acid-labile carbon dioxide in muscle: its nature and relationship to intracellular pH. Proc. Soc. Exp. Biol. (N. Y.)125, 972–974 (1967)Google Scholar
  4. 4.
    Caldwell, P. C.: An investigation of the intracellular pH of crab muscle fibers by means of micro-glass and micro-tungsten electrodes. J. Physiol. (Lond.)126, 169–180 (1954)Google Scholar
  5. 5.
    Caldwell, P. C.: Studies on the internal pH of large muscle and nerve fibers. J. Physiol. (Lond.)142, 22–62 (1958)Google Scholar
  6. 6.
    Carter, N. W., Rector, F. C., Campion, D. S., Seldin, D. W.: Measurement of intracellular pH of skeletal muscle with pH-sensitive glass microelectrodes. J. Clin. Invest.46, 920–933 (1967)Google Scholar
  7. 7.
    Clancy, R. L., Brown, E. B.: In vivo CO2 buffere curves of skeletal and cardiac muscle. Amer. J. Physiol.211, 1309–1312 (1966)Google Scholar
  8. 8.
    Conway, E. J.: Nature and significance of concentration relations of potassium and sodium ions in skeletal muscle. Physiol. Rev.37, 84–132 (1957)Google Scholar
  9. 9.
    Conway, E. J., Fearon, P. J.: The acid-labile CO2 in mammalian muscle and the pH of the muscle fibre. J. Physiol. (Lond.)103, 274–289 (1944)Google Scholar
  10. 10.
    Fenn, W. O., Cobb, D. M., Manery, J. F., Bloor, W. R.: Electrolyte changes in cat muscle during stimulation. Amer. J. Physiol.121, 595–608 (1937)Google Scholar
  11. 11.
    Khuri, R. N., Agulian, S. K., Kalloghlian, A.: Intracellular potassium in cells of the distal tubule. Pflügers Arch.335, 297–308 (1972)Google Scholar
  12. 12.
    Khuri, R. N., Hajjar, J. J., Agulian, S.: Measurement of intracellular potassium with liquid ion-exchange microelectrodes. J. appl. Physiol.32, 419–422 (1972)Google Scholar
  13. 13.
    Khuri, R., Hajjar, J. J., Agulian, S., Bogharian, K., Kalloghlian, A., Bizri, H.: Intracellular potassium in cells of the proximal tubule of Necturus maculosus. Pflügers Arch.338, 73–80 (1972)Google Scholar
  14. 14.
    Kostyuk, P. G., Sorokina, Z. A.: On the mechanism of hydrogen ion distribution between cell protoplasm and medium. In: Membrane Transport and Metabolism, edit. by A. Kleinzeller and A. Kotyk, pp. 193–203. New York: Academic Press 1960Google Scholar
  15. 15.
    Kostyuk, P. G., Sorokina, Z. A., Kholodova, Yu. D.: Measurement of the activity of hydrogen, potassium, and sodium ions in striated muscle fibers and nerve cells. In: Glass Microelectrodes edit. by M. Lavallée, O. F. Schanne, and N. C. Hébert, pp. 331–348. New York: John Wiley 1969Google Scholar
  16. 16.
    Lev, A. A.: Determination of activity coefficients of potassium and sodium in frog muscle fibers. Nature (Lond.)201, 1132–1134 (1964)Google Scholar
  17. 17.
    Ling, G., Gerard, R. W.: The normal membrane potential of frog sartorius fibres. J. Cell. Comp. Physiol.34, 382–396 (1949)Google Scholar
  18. 18.
    Miller, R. B., Tyson, I., Relman, A. S.: pH of isolated resting skeletal muscle and its relation to potassium content. Amer. J. Physiol.204, 1048–1054 (1963)Google Scholar
  19. 19.
    Paillard, M.: Direct intracellular pH measurement in rat and crab muscle. J. Physiol. (Lond.)223, 297–319 (1972)Google Scholar
  20. 20.
    Waddell, W. J., Butler, T. C.: Calculation of intracellular pH from the distribution of 5, 5-dimethyl-2,4-oxazolidinedione (DMO). Application to skeletal muscle of the dog. J. Clin. Invest.38, 720–729 (1959)Google Scholar

Copyright information

© Springer-Verlag 1974

Authors and Affiliations

  • R. N. Khuri
    • 1
  • K. K. Bogharian
    • 1
  • S. K. Agulian
    • 1
  1. 1.Department of PhysiologyAmerican University of BeirutBeirutLebanon

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