Advertisement

The Journal of Membrane Biology

, Volume 45, Issue 3–4, pp 245–276 | Cite as

Cation permeation at the amphibian motor end-plate

  • Peter H. Barry
  • Peter W. Gage
  • Dirk F. Van Helden
Article

Summary

Measurements of acetylcholine-induced single-channel conductance and null potentials at the amphibian motor end-plate in solutions containing Na, K, Li and Cs ions (Gage & Van Helden, 1979;J. Physiol. (London) (in press) were analyzed in terms of three models. Two of these models, the “neutral” site channel model and the “charged” site channel model were developed to cater for three cations. Both were shown to be able to explain the dependence of single-channel conductance on membrane potential and gave the following sequences of equilibrium constants and mobilities.KLi/KNa/KK/KCs=7∶1.7∶1∶0.9 anduCs/uK/uNa/uLi=1.4∶1∶0.58∶0.13 at 8 °C. Similar sequences were obtained at 20 °C. Although the neutral model fitted the data for relative conductances in Li-, Cs-and Na-solutions slightly better than the charged model, experiments done in normal [NaCl] and [NaCl]/2 solutions could only be fitted by the neutral model. In contrast, the third model, the Constant Field Equation, was unable to fit the conductance data in any of the above situations. The data available suggests that permeation is through “long” neutral channels, lined with high field-strength negative polar groups and including one or possibly more high resistance barriers for anions.

Keywords

Membrane Potential Similar Sequence Human Physiology Equilibrium Constant High Resistance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Barry, P.H. 1978. Ion permeation through long neutral and charged channels in membranes.Proc. Aust. Soc. Biophys. 2:1A Google Scholar
  2. Barry, P.H., Adrian, R.H. 1973. Slow conductance changes due to potassium depletion in the transverse tubules of frog muscle fibers during hyperpolarizing pulses.J. Membrane Biol. 14:243Google Scholar
  3. Barry, P.H., Diamond, J.M. 1970. Junction potentials, electrode standard potentials, and other problems in interpreting electrical properties of membranes.J. Membrane Biol. 3:93Google Scholar
  4. Barry, P.H., Diamond, J.M. 1971. A theory of ion permeation through membranes with fixed neutral sites.J. Membrane Biol. 4:295Google Scholar
  5. Barry, P.H., Gage, P.W., Van Helden, D.F. 1978. Movements of cations through end-plate channels.Proc. Aust. Physiol. Pharmacol. Soc. 9:125P Google Scholar
  6. Conti, F., Eisenman, G. 1965. The steady-state properties of ion exchange membranes with fixed sites.Biophys. J. 5:512Google Scholar
  7. Diamond, J.M., Wright, E.M. 1969. Biological membranes: The physical basis of ion and non-electrolyte selectivity.Annu. Rev. Physiol. 31:581PubMedGoogle Scholar
  8. Eisenman, G. 1965. Some elementary factors involved in specific ion permeation. Proceedings of the XXIIIrd International Congress of Physiological Sciences, Tokyo.Reprinted from Excerpta Med. Int. Cong. Ser. 87:489Google Scholar
  9. Eisenman, G. 1968. Ion permeation of cell membranes and its models.Fed. Proc. 27:1249PubMedGoogle Scholar
  10. Eisenman, G., Sandblom, J., Neher, E. 1978. Interactions in cation permeation through the gramicidin channel.Biophys. J. 22:307PubMedGoogle Scholar
  11. Gage, P.W., McBurney, R.N., Van Helden, D.F. 1978. Octanol reduces end-plate channel lifetime.J. Physiol. (London) 274:279Google Scholar
  12. Gage, P.W., Van Helden, D.F. 1979. Effects of permeant monovalent cations on end-plate channels.J. Physiol. (London) (in press) Google Scholar
  13. Goldman, D.E. 1943. Potential, impedance and rectification in membranes.J. Gen. Physiol. 27:37Google Scholar
  14. Hille, B. 1975. Ion selectivity of Na and K channels of nerve membranes.In: Membranes—A Series of Advances. Vol. 3, pp. 255–324. G. Eisenman, editor. Marcel Dekker, New YorkGoogle Scholar
  15. Hodgkin, A.L., Horowicz, P. 1959. The influence of potassium and chloride ions on the membrane potential of single muscle fibres.J. Physiol. (London) 148:127Google Scholar
  16. Hodgkin, A.L., Katz, B. 1949. The effect of sodium ions on the electrical activity of the giant axon of the squid.J. Physiol. (London) 108:37Google Scholar
  17. Jaffe, L.F. 1974. The interpretation of voltage-concentration relations.J. Theor. Biol. 48:11PubMedGoogle Scholar
  18. Katz, B. 1966. Nerve, Muscle and Synapse. McGraw Hill, New YorkGoogle Scholar
  19. Lassignal, N.L., Martin, A.R. 1977. The effect of acetylcholine on post-junctional membrane permeability in eel electroplaque.J. Gen. Physiol. 70:23PubMedGoogle Scholar
  20. Läuger, P. 1973. Ion transport through pores: A rate-theory analysis.Biochim. Biophys. Acta 311:423PubMedGoogle Scholar
  21. Läuger, P., Neumcke, B. 1973. Theoretical analysis of ion conductance in lipid bilayer membranes.In: Membranes—A Series of Advances. Vol. 2, pp. 1–59. G. Eisenman, editor. Marcel Dekker, New YorkGoogle Scholar
  22. MacInnes, D.A. 1961. The Principles of Electrochemistry. Dover Publications, New YorkGoogle Scholar
  23. Moreno, J.H., Diamond, J.M. 1975. Cation permeation mechanisms and cation selectivity in “tight junctions” of gall bladder epithelium.In: Membranes—A Series of Advances. Vol. 3, pp. 383–497. G. Eisenman, editor, Marcel Dekker, New YorkGoogle Scholar
  24. Neher, E., Sandblom, J., Eisenman, G. 1978. Ionic selectivity, saturation and block in gramicidin A channels. II. Saturation behavior of single channel conductances and evidence for the existence of multiple binding sites in the channel.J. Membrane Biol. 40:97Google Scholar
  25. Ralston, A. 1965. A First Course in Numerical Analysis. McGraw Hill, New YorkGoogle Scholar
  26. Sandblom, J., Eisenman, G., Neher, E. 1977. Ionic selectivity, saturation and block in gramicidin A Channels. I. Theory for the electrical properties of ion selective channels having two pairs of binding sites and multiple conductance states.J. Membrane Biol. 31:383Google Scholar
  27. Takeuchi, A., Takeuchi, N. 1960. On the permeability of end-plate channel membrane during the action of transmitter.J. Physiol. (London) 154:52Google Scholar

Copyright information

© Springer-Verlag New York Inc 1979

Authors and Affiliations

  • Peter H. Barry
    • 1
  • Peter W. Gage
    • 1
  • Dirk F. Van Helden
    • 1
  1. 1.School of Physiology & PharmacologyUniversity of New South WalesKensingtonAustralia

Personalised recommendations