Pflügers Archiv

, Volume 345, Issue 1, pp 61–72 | Cite as

The electrical activity of the bundle of His

The fast and slow inward currents
  • Daisy Benítez
  • Dieter Mascher
  • Jesus Alanis
Article

Summary

Transmembrane action potentials were recorded from fibers of the atrioventricular region of the rabbit heart.

Displacement of the recording microelectrode from the A.V. node towards the distal segment of the bundle of His revealed that the rate of rise and amplitude of the action potentials increased gradually along the bundle. According to these characteristics and to the site from which the action potentials were recorded, they were classified in three groups: upper His (UH), middle His (MH) and lower His (LH).

The effects of some specific blocking agents of the ionic fluxes were studied on the electrical activity of the fibers of the bundle of His. Tetrodotoxin (5 μg/ml) and high KCl (18.9 and 27.0 mM/l) were used to abolish the fast excitatory current, and MnCl2 (5 mM/l) to block the slow inward current.

The present results indicate that both the fast and the slow inward currents participate in the generation of the action potentials of the bundle of His. The proportion of each current varies, depending on the segment of the bundle of His in which the action potentials were originated. In the cells of the upper bundle the upstroke of the action potentials is determined mainly by the activation of the slow inward current with a negligible contribution from the fast sodium current. Along the bundle of His the participation of the fast inward current increases progressively.

Key words

Heart Electrical Activity Bundle of His Transmembrane Currents Sodium and Calcium Ions 

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References

  1. Alanís, J., Benítez, D.: Action potential from A.V. node transitional cells. Arch intern. Physiol. Biochem.72, 765–775 (1964)Google Scholar
  2. Alanís, J., Benítez, D.: Transitional potentials and the propagation of impulses through different cardiac cells. In: Electrophysiology and ultrastructure of the heart. Ed. by T. Sano, V. Mizuhira, and K. Matsuda. Tokyo: Bunkodo, Co., Ltd. 1967Google Scholar
  3. Beeler, G. W., Jr., Reuter, H.: Membrane calcium current in ventricular myocardial fibers. J. Physiol. (Lond.)207, 191–209 (1970)Google Scholar
  4. Carmeliet, E., Vereecke, J.: Adrenaline and the plateau phase of the cardiac action potential. Pflügers Arch.313, 300–315 (1969)Google Scholar
  5. Dudel, J., Peper, K., Rüdel, R., Trautwein, W.: Effect of tetrodotoxin on the membrane current in cardiac muscle (Purkinje fibers). Pflügers Arch. ges. Physiol.295, 213–226 (1967)Google Scholar
  6. Goto, M., Kimoto, Y., Kato, Y.: A study on the excitation-contraction coupling of the bullfrog ventricle with voltage clamp technique. Jap. J. Physiol.21, 159–173 (1971)Google Scholar
  7. Hagiwara, S., Nakajima, S.: Differences in Na and Ca spikes as examined by application of tetrodotoxin, procaine and Mn ion. J. gen. Physiol.49, 793–806 (1966)Google Scholar
  8. Hoffman, B. F., Cranefield, P. F.: Electrophysiology of the heart. Ed. by McGraw-Hill, Co. New York: Blakiston Division 1960Google Scholar
  9. Kohlhardt, M., Bauer, B., Krause, H., Fleckenstein, A.: Differentiation of the transmembrane Na and Ca channels in mammalian cardiac fibers by the use of specific inhibitors. Pflügers Arch.335, 309–322 (1972)Google Scholar
  10. Kohlhardt, M., Bauer, B., Krause, H., Fleckenstein, A.: Selective inhibition of the transmembrane Ca conductivity of mammalian myocardial fibers by Ni, Co and Mn ions. Pflügers Arch.338, 115–123 (1973)Google Scholar
  11. Mascher, D., Peper, K.: Two components of inward current in muscle fibers. Pflügers Arch.307, 190–203 (1969)Google Scholar
  12. McDonald, T. F., MacLeod, D. P.: Effects of manganese, glucose and isoprenaline on the action potential of anoxic ventricular muscle. Naunyn-Schmiedeberg's Arch. exp. Pharmacol.275, 169–181 (1972)Google Scholar
  13. Myerburg, R. J., Steward, J. W., Hoffman, B. F.: Electrophysiological properties of the canine peripheral A-V conducting system. Circulat. Res.26, 361–378 (1970)Google Scholar
  14. Ochi, R.: The slow inward current and the action of manganese ions in guinea-pig myocardium. Pflügers Arch.316, 81–94 (1970)Google Scholar
  15. Paes de Carvalho, A., Hoffman, B. F., Carvalho, M. de P.: Two components of the cardiac action potential. I. Voltage-time course and the effect of acetylcholine on atrial and nodal cells of the rabbit heart. J. gen. Physiol.54, 607–635 (1969)Google Scholar
  16. Reuter, H.: The dependence of slow inward current in Purkinje fibers on the extracellular calcium concentration. J. Physiol. (Lond.)192, 479–492 (1967)Google Scholar
  17. Rougier, O., Vassort, G., Garnier, D., Gargouil, Y. M., Coraboeuf, E.: Existence and role of a slow inward current during the frog atrial action potential. Pflügers Arch.308, 91–110 (1969)Google Scholar
  18. Sano, T., Tasaki, M., Shimamoto, T.: Histological examination of the origin of the action potential characteristically obtained from the region bordering the atrioventricular node. Circulat. Res.7, 700–704 (1959)Google Scholar
  19. Takashi, Y., Holland, W. C.: Effect of manganese on transmembrane potential and contractility of atrial muscle. Amer. J. Physiol.217, 1280–1286 (1969)Google Scholar
  20. Takeya, K., Reiter, M.: Effect of divalent manganese ions on action potential and contractility of cardiac muscle. Naunyn-Schmiedeberg's Arch. exp. Pharmacol.275, 213–226 (1972)Google Scholar
  21. Tarr, M.: Two inward currents in frog atrial muscle. J. gen. Physiol.58, 523–543 (1971)Google Scholar
  22. Vassort, G., Rougier, O., Garnier, D., Coraboeuf, E., Gargouil, Y. M.: Effects of adrenaline on membrane inward currents during the cardiac action potential. Pflügers Arch.309, 70–81 (1969)Google Scholar
  23. Vitek, M., Trautwein, W.: Slow inward current and action potential in cardiac Purkinje fibers. Pflügers Arch.323, 204–218 (1971)Google Scholar
  24. Weidmann, S.: Electrophysiologie der Herzmuskelfaser. Bern-Stuttgart: Huber 1956Google Scholar

Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • Daisy Benítez
    • 1
  • Dieter Mascher
    • 1
  • Jesus Alanis
    • 1
  1. 1.Department of PhysiologyInstituto Nacional de CardiologíaMéxico 7México

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