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The Journal of Membrane Biology

, Volume 62, Issue 3, pp 207–218 | Cite as

Excitation-revealed changes in cytoplasmic Cl concentration in “Cl-starved”Chara cells

  • M. J. Beilby
Articles

Summary

The changes in the cytoplasmic Cl concentration, [Cl] c , are monitored at the time of withdrawal (starvation) and subsequent replacement of Cl in the outside medium. The measurement technique exploits the involvement of Cl inChara excitation. The transient clamp current due to Cl,ICl, is separated from other excitation transients through Hodgkin-Huxley (HH) equations, which have been adjusted toChara. TheICl amplitude depends on HH parameters, [Cl] c and the maximum membrane conductance to Cl,\(\overline {g_{Cl} } \). The results are discussed in terms of these quantities.ICl and\(\overline {g_{Cl} } \) were found to fall after 6–10 hr of Cl starvation, thus supporting the hypothesis that [Cl c decreases in Cl-free medium. The best HH fit to “starved” data was obtained with [Cl c =3.5mm. The time-course forICl decline is considerably slower than the time-course of the rise of the starvation-stimulated influx. As cells starved for periods longer than 24 hr are re-exposed to Cl, it is revealed that while [Cl] c remains low during long starvation,\(\overline {g_{Cl} } \) increases to values greater than those of the normal cells. Such differences among cells starved for various lengths of time have not been detected previously.

Key words

Chara voltage clamp cytoplasm action potential Cl concentration Cl transport Cl starvation 

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References

  1. Beilby, M.J. 1977. An Investigation into the Electrochemical Properties of Cell Membranes During Excitation. Ph.D. Thesis. pp. 97–105. University of New South Wales, AustraliaGoogle Scholar
  2. Beilby, M.J., Coster, H.G.L. 1979a. The action potential inChara corallina. II. Two activation-inactivation transients in voltage clamps of the plasmalemma.Aust. J. Plant Physiol. 6:323–335Google Scholar
  3. Beilby, M.J., Coster, H.G.L. 1979b. The action potential inChara corallina. III. The Hodgkin-Huxley parameters for the plasmalemma.Aust. J. Plant Physiol. 6:337–353Google Scholar
  4. Beilby, M.J., Coster, H.G.L. 1979c. The action potential inChara corallina. IV. Activation enthalpies of the Hodgkin-Huxley gates.Aust. J. Plant Physiol. 6:355–365Google Scholar
  5. Beilby, M.J., Walker, N.A.W. 1980. Chloride influx inChara: Electrogenic and probably proton-coupled.In: Plant Membrane Transport: Current Conceptual Issues. R.M. Spanswick, W.J. Lucas, and J. Dainty, editors. pp. 571–572. Elsevier/North Holland, AmsterdamGoogle Scholar
  6. Beilby, M.J., Walker, N.A.W. 1981. Chloride transport inChara: I. Kinetics and current voltage curves for probable proton symport.J. Exp. Bot. 126:43–54Google Scholar
  7. Bell, D.J., Coster, H.G.L., Smith, J.R. 1975. A computer based, four-terminal impedance measuring system for low frequencies.J. Phys. E:8:66–70Google Scholar
  8. Coster, H.G.L. 1966. Chloride in cells ofChara australis.Aust. J. Biol. Sci. 19:545–554Google Scholar
  9. Findlay, G.P., Hope, A.B. 1964. Ionic relations of cells ofChara australis. IX. Analysis of transient membrane currents.Aust. J. Biol. Sci. 17:400–411Google Scholar
  10. Goldman, D.E. 1943. Potential, impedance and rectification in membranes.J. Gen. Physiol. 27:37–60Google Scholar
  11. Hodgkin, A.L., Huxley, A.F. 1952a. A quantitative description of membrane current and its application to conduction and excitation in nerve.J. Physiol. (London) 117:500–544Google Scholar
  12. Hodgkin, A.L., Huxley, A.F. 1952b. The dual effect of membrane potential on sodium conductance in the giant axon ofLoligo.J. Physiol. (London) 116:497–506Google Scholar
  13. Hope, A.B., Simpson, A., Walker, N.A.W. 1966. The efflux of chloride from cells ofNitella andChara.Aust. J. Biol. Sci. 19:355–362Google Scholar
  14. Jones, S., Walker, N.A. 1980. Chloride compartmentation inChara corallina by efflux analysis.In: Plant Membrane Transport. R.M. Spanswick, W.J. Lucas and J. Dainty, editors. pp. 583–584. Elsevier/North Holland, AmsterdamGoogle Scholar
  15. Kishimoto, U., Kami-ike, N., Takeuchi, Y. 1980. The role of electrogenic pump inChara corallina.J. Membrane Biol. 55:149–156Google Scholar
  16. Kishimoto, U., Tazawa, M. 1965. Ionic composition of the cytoplasm ofNitella flexilis.Plant Cell Physiol. 6:507–518Google Scholar
  17. Lefevre, J., Gillet, C. 1970. Variations de la difference de potential electrochimique des chlorures chezNitella en presence de benzenesulphonate.Experientia 26:482–483PubMedGoogle Scholar
  18. Lefevre, J., Gillet, C. 1971. Effects des cations externes sur l'activite des chlorures cytoplasmiques doses par l'electrode Ag−AgCl introduite dans la cellule deNitella.Biochim. Biophys. Acta 249:556–563PubMedGoogle Scholar
  19. Reid, R. 1980. A Study of Adenylate Concentrations and Chloride Active Transport inChara corallina. Ph.D. Thesis. pp. 98–113. University of Sydney, AustraliaGoogle Scholar
  20. Richards, J.L., Hope, A.B., 1974. The role of protons in determining membrane electrical characteristics inChara corallina.J. Membrane Biol. 16:121–144Google Scholar
  21. Sanders, D. 1978. Regulation of Ion Transport in Characean Cells. Ph.D. Thesis. University of Cambridge, EnglandGoogle Scholar
  22. Sanders, D. 1980a. Control of Cl influx inChara by cytoplasmic Cl concentration.J. Membrane Biol. 52:51–60Google Scholar
  23. Sanders, D. 1980b. The mechanism of Cl transport at the plasma membrane ofChara corallina. I. Co transport with H+.J. Membrane Biol. 53:129–141Google Scholar
  24. Sanders, D., Hansen, U.-P. 1981. Mechanism of Cl transport at the plasma membrane ofChara corallina. II. Transinhibition and the determination of H+/Cl binding order from a reaction kinetic model.J. Membrane Biol. 58:139–153Google Scholar
  25. Shimmen, T., Tazawa, M. 1980. Intracellular chloride and potassium ions in relation to excitability ofChara membrane.J. Membrane Biol. 55:223–232Google Scholar
  26. Smith, F.A. 1970. The mechanisms of chloride transport in characean cells.New Phytol. 69:903–917Google Scholar
  27. Smith, F.A. 1972. Stimulation of chloride transport inChara by external pH changes.New Phytol. 71:595–601Google Scholar
  28. Smith, F.A. 1981. Comparison of cytoplasmic pH and Cl influx in cells ofChara corallina following “Cl-starvation”.J. Exp. Bot. (in press) Google Scholar
  29. Smith, F.A., Walker, N.A. 1976. Chloride transport inChara corallina and the electrochemical potential difference for hydrogen ions.J. Exp. Bot. 27:451–459Google Scholar
  30. Spanswick, R.M., Williams, E.J. 1964. Electric potentials and Na, K and Cl concentrations in the vacuole and cytoplasm ofNitella translucens.J. Exp. Bot. 15:193–200Google Scholar
  31. Tazawa, M., Kishimoto, U., Kikuyama, M. 1974. Potassium, sodium and chloride in the protoplasm of characeae.Plant Cell Physiol. 15:103–110Google Scholar

Copyright information

© Springer-Verlag New York Inc. 1981

Authors and Affiliations

  • M. J. Beilby
    • 1
  1. 1.Botany SchoolCambridgeEngland

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