Advertisement

Pflügers Archiv

, Volume 390, Issue 1, pp 102–106 | Cite as

Inhibition of transient outward current by intracellular ion substitution unmasks slow inward calcium current in cardiac Purkinje fibers

  • Eduardo Marban
Excitable Tissues and Central Nervous Physiology Letters and Notes

Abstract

The ionophore nystatin was used to replace intracellular K+ with Cs+ in calf Purkinje fibers. Such replacement inhibited the transient outward current, and unmasked a large slow inward current (Isi). These results support the involvement of K+ as a charge carrier of the transient outward current, and suggest a method for better analysis of Isi.

Key words

calcium current Purkinje fiber voltage clamp nystatin cesium 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Armstrong, C.M. (1975). Potassium pores of nerve and muscle membranes. In: Eisenman G (ed.)Membranes, Vol. 3. Lipid bilayers and biological membranes: dynamic properties. Chapter 5. Marcel Dekker, N.Y., p. 325.Google Scholar
  2. Cass, A., Dalmark, M.(1973). Equilibrium dialysis of ions in nystatin-treated red cells.Nature New Biol. 244:47–49.Google Scholar
  3. Cass, A., Finkelstein, A., Krespi, V. (1970). The ion permeability induced in thin lipid membranes by the polyene antibiotics nystatin and amphotericin B.J. Gen. Physiol. 56: 100–124.Google Scholar
  4. Deck, K.A., Kern, R., Trautwein, W.. (1964). Veltage clamp technique in mammalian cardiac fibres.Pflügers Arch. 280:50–62.Google Scholar
  5. Dudel, J., Peper, K., Rudel, R., Trautwein, W. (1967). The dynamic chloride component of membrane current in Purkinje fibres.Pflügers Arch. 295: 197–212.Google Scholar
  6. Fozzard, H.A. (1977). Heart: excitation-contraction coupling.Ann. Rev. Physiol. 39: 201–220.Google Scholar
  7. Fozzard, H.A., Beeler, G.W. (1975). The voltage clamp and cardiac electrophysiology.Circ. Res. 37: 403–413.Google Scholar
  8. Fozzard, H.A., Hiraoka, M. (1973). The positive dynamic current and its inactivation properties in cardiac Purkinje fibers.J. Physiol. 234: 569–586.Google Scholar
  9. Gibbons, W.R., Fozzard, H.A., (1975). Slow inward current and contraction of sheep cardiac Purkinje fibers.J. Gen. Physiol. 65: 367–384.Google Scholar
  10. Guerin, M., Wallon, G. (1979). The reversible replacement of internal potassium by caesium in isolated turtle heart.J. Physiol. 293: 525–537.Google Scholar
  11. Hille, B. (1975). Ionic selectivities of Na and K channels of nerve membranes. In: Eisenman, G (ed.)Membranes, Vol. 3. Lipid bilayers and biological membranes: dynamic properties. Chapter 4. Marcel Dekker, N.Y., p. 255.Google Scholar
  12. Hiraoka, M., Hiraoka, M. (1975). The role of the positive dynamic current on the action potential of cardiac Purkinje fibers.Jap. J. Physiol. 25: 705–717.Google Scholar
  13. Kenyon, J.L., Gibbons, W.R. (1977). Effects of low-chloride solutions on action potentials of sheep cardiac Purkinje fibers.J. Gen. Physiol. 70: 635–660.Google Scholar
  14. Kenyon, J.L., Gibbons, W.R., (1979a). Influence of chloride, potassium, and tetraethylammonium on the early outward current of sheep cardiac Purkinje fibers.J. Gen. Physiol. 73: 117–138.Google Scholar
  15. Kenyon, J.L., Gibbons, W.R. (1979b). 4-aminopyridine and the early outward current of sheep cardiac Purkinje fibers.J. Gen. Physiol. 73: 139–157.Google Scholar
  16. Lee, K.S., Weeks, T.A., Kao, R.L., Akaike, N. Brown, A.M. (1979). Sodium current in single heart cells.Nature 278: 269–271.Google Scholar
  17. McDonald, T.F., Pelzer, D., Trautwein, W. (1980). On the mechanism of slow calcium channel block in heart.Pflügers Arch. 385: 175–179.Google Scholar
  18. New, W., Trautwein, W. (1972). Inward membrane currents in mammalian myocardium.Pflügers Arch. 334: 1–23.Google Scholar
  19. Noble, D., Tsien, R.W. (1969). Outward membrane currents activated in the plateau range of potentials i in cardiac Purkinje fibres.J. Physiol. 200: 205–231.Google Scholar
  20. Peper, K., Trautwein, W. (1968). A membrane current related to the plateau of the action potential of Purkinje fibers.Pflügers Arch. 303: 108–123.Google Scholar
  21. Reuter, H. (1979). Properties of two inward membrane currents in the heart.Ann. Rev. Physiol. 41: 413–424.Google Scholar
  22. Russell, J.M., Eaton, D.C., Brodwick, M.S. (1977). Effects of nystatin on membrane conductance and internal ion activities inAplysia neurons.J. Membrane Biol. 37: 137–156.Google Scholar
  23. Siegelbaum, S. (1978). Calcium-sensitive currents in cardiac Purkinje fibers. Doctoral thesis, Yale University.Google Scholar
  24. Siegelbaum, S.A., Tsien, R.W. (1980). Calcium-activated transient outward current in cardiac Purkinje fibres.J. Physiol. 299: 485–506.Google Scholar
  25. Siegelbaum, S.A., Tsien, R.W., Kass, R.S. (1977). Role of intracellular calcium in the transient outward current of calf Purkinje fibres.Nature 269: 611–613.Google Scholar
  26. Tillotson, D. (1979). Inactivation of Ca conductance dependent on entry of Ca ions in molluscan neurons.Proc. Natl. Acad. Sci. USA 76: 1497–1500.Google Scholar
  27. Tillotson, D., Horn, R. (1978). Inactivation without facilitation of calcium conductance in cesium-loaded neurones ofAplysia.Nature 273: 312–314.Google Scholar
  28. Vereecke, J., Isenberg, G., Carmeliet, E. (1980). K efflux through inward rectifying K channels in voltage clamped Purkinje fibers.Pflügers Arch.384: 207–217.Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Eduardo Marban
    • 1
  1. 1.Department of PhysiologyYale UniversityNew HavenUSA

Personalised recommendations