Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1996 Jan 1;490(Pt 1):51–62. doi: 10.1113/jphysiol.1996.sp021126

Sodium--potassium pump current in rabbit sino-atrial node cells.

R Sakai 1, N Hagiwara 1, N Matsuda 1, H Kassanuki 1, S Hosoda 1
PMCID: PMC1158647  PMID: 8745278

Abstract

1. The Na(+)-K+ pump current (Ip) was studied in sino-atrial (SA) node cells of rabbits using the whole-cell patch-clamp technique. 2. With 50 mM Na+ in the pipette solution ([Na+]pip), changing the external K+ concentration (-K+-o) from 0 to 5.4 mM caused the holding current to shift in an outward direction and reach a new steady state. The current-voltage relationships obtained by subtraction of current traces recorded at 0 mM Ko+ from those recorded at 5.4 mM Ko+ revealed time-independent and voltage-dependent characteristics. The external K(+)-induced current was completely blocked by external application of 10 microM ouabain, indicating the existence of Ip in SA node cells of rabbit heart. 3. Ip increased as [K+]o increased. With 30 mM Na+pip, Ip at 0 mV was activated by [K+]o with non-linear least-squares fit parameters for the Hill equation of K0.5 of 1.4 mM and a Hill coefficient (nH) of 1.2 (n = 7). 4. The cation dependence of the K+ site of the Na(+)-K+ pump was examined using various monovalent cations. The sequence was K+ > or = Rb+ > Cs+ > > > Li+. 5. Ip at 0 mV also increased as [Na+]pip was increased from 10 to 150 mM at 5.4 mM Ko+, with a K0.5 value of 14 mM and a nH of 1.3 (n = 54). 6. Ip at 0 mV was reduced by lowering the temperature from 37 to 25 degrees C with 30 mM Na+pip and 5.4 mM Ko+. The temperature coefficient (Q10) for Ip was 2.1 (n = 27). 7. With 10 mM Na+pip and 5.4 mM Ko+, the half-activation voltage of Ip was -52 +/- 16 mV and the current at this voltage was 22.5 +/- 3.5 pA (n = 10), indicating that Ip contributes significantly to the background outward current during the normal pacemaker potential of SA node cells.

Full text

PDF
51

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bielen F. V., Glitsch H. G., Verdonck F. Dependence of Na+ pump current on external monovalent cations and membrane potential in rabbit cardiac Purkinje cells. J Physiol. 1991 Oct;442:169–189. doi: 10.1113/jphysiol.1991.sp018788. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. De Weer P., Gadsby D. C., Rakowski R. F. Voltage dependence of the Na-K pump. Annu Rev Physiol. 1988;50:225–241. doi: 10.1146/annurev.ph.50.030188.001301. [DOI] [PubMed] [Google Scholar]
  3. EISENMAN G. Cation selective glass electrodes and their mode of operation. Biophys J. 1962 Mar;2(2 Pt 2):259–323. doi: 10.1016/s0006-3495(62)86959-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Eisner D. A., Lederer W. J. The relationship between sodium pump activity and twitch tension in cardiac Purkinje fibres. J Physiol. 1980 Jun;303:475–494. doi: 10.1113/jphysiol.1980.sp013299. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Eisner D. A., Lederer W. J. The role of the sodium pump in the effects of potassium-depleted solutions on mammalian cardiac muscle. J Physiol. 1979 Sep;294:279–301. doi: 10.1113/jphysiol.1979.sp012930. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Gadsby D. C., Kimura J., Noma A. Voltage dependence of Na/K pump current in isolated heart cells. Nature. 1985 May 2;315(6014):63–65. doi: 10.1038/315063a0. [DOI] [PubMed] [Google Scholar]
  7. Gadsby D. C., Nakao M. Steady-state current-voltage relationship of the Na/K pump in guinea pig ventricular myocytes. J Gen Physiol. 1989 Sep;94(3):511–537. doi: 10.1085/jgp.94.3.511. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Glitsch H. G., Krahn T., Pusch H. The dependence of sodium pump current on internal Na concentration and membrane potential in cardioballs from sheep Purkinje fibres. Pflugers Arch. 1989 May;414(1):52–58. doi: 10.1007/BF00585626. [DOI] [PubMed] [Google Scholar]
  9. Glitsch H. G., Pusch H. On the temperature dependence of the Na pump in sheep Purkinje fibres. Pflugers Arch. 1984 Sep;402(1):109–115. doi: 10.1007/BF00584839. [DOI] [PubMed] [Google Scholar]
  10. Hagiwara N., Irisawa H., Kameyama M. Contribution of two types of calcium currents to the pacemaker potentials of rabbit sino-atrial node cells. J Physiol. 1988 Jan;395:233–253. doi: 10.1113/jphysiol.1988.sp016916. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hagiwara N., Irisawa H., Kasanuki H., Hosoda S. Background current in sino-atrial node cells of the rabbit heart. J Physiol. 1992 Mar;448:53–72. doi: 10.1113/jphysiol.1992.sp019029. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  13. Hasuo H., Koketsu K. Potential dependency of the electrogenic Na+-pump current in bullfrog atrial muscles. Jpn J Physiol. 1985;35(1):89–100. doi: 10.2170/jjphysiol.35.89. [DOI] [PubMed] [Google Scholar]
  14. Irisawa H., Brown H. F., Giles W. Cardiac pacemaking in the sinoatrial node. Physiol Rev. 1993 Jan;73(1):197–227. doi: 10.1152/physrev.1993.73.1.197. [DOI] [PubMed] [Google Scholar]
  15. Isenberg G., Klockner U. Calcium tolerant ventricular myocytes prepared by preincubation in a "KB medium". Pflugers Arch. 1982 Oct;395(1):6–18. doi: 10.1007/BF00584963. [DOI] [PubMed] [Google Scholar]
  16. JOHANSEN K. REGIONAL DISTRIBUTION OF CIRCULATING BLOOD DURING SUBMERSION ASPHYXIA IN THE DUCK. Acta Physiol Scand. 1964 Sep-Oct;62:1–9. doi: 10.1111/j.1748-1716.1964.tb03945.x. [DOI] [PubMed] [Google Scholar]
  17. Kinard T. A., Liu X. Y., Liu S., Stimers J. R. Effect of Napip on K0 activation of the Na-K pump in adult rat cardiac myocytes. Am J Physiol. 1994 Jan;266(1 Pt 1):C37–C41. doi: 10.1152/ajpcell.1994.266.1.C37. [DOI] [PubMed] [Google Scholar]
  18. Kurachi Y., Noma A., Irisawa H. Electrogenic sodium pump in rabbit atrio-ventricular node cell. Pflugers Arch. 1981 Oct;391(4):261–266. doi: 10.1007/BF00581504. [DOI] [PubMed] [Google Scholar]
  19. Lee C. O., Fozzard H. A. Activities of potassium and sodium ions in rabbit heart muscle. J Gen Physiol. 1975 Jun;65(6):695–708. doi: 10.1085/jgp.65.6.695. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Nakao M., Gadsby D. C. Voltage dependence of Na translocation by the Na/K pump. Nature. 1986 Oct 16;323(6089):628–630. doi: 10.1038/323628a0. [DOI] [PubMed] [Google Scholar]
  21. Nakao M., Gadsby D. C. [Na] and [K] dependence of the Na/K pump current-voltage relationship in guinea pig ventricular myocytes. J Gen Physiol. 1989 Sep;94(3):539–565. doi: 10.1085/jgp.94.3.539. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Noma A., Irisawa H. Contribution of an electrogenic sodium pump to the membrane potential in rabbit sinoatrial node cells. Pflugers Arch. 1975 Aug 12;358(4):289–301. doi: 10.1007/BF00580527. [DOI] [PubMed] [Google Scholar]
  23. Noma A., Irisawa H. Electrogenic sodium pump in rabbit sinoatrial node cell. Pflugers Arch. 1974;351(2):177–182. doi: 10.1007/BF00587436. [DOI] [PubMed] [Google Scholar]
  24. Sejersted O. M., Wasserstrom J. A., Fozzard H. A. Na,K pump stimulation by intracellular Na in isolated, intact sheep cardiac Purkinje fibers. J Gen Physiol. 1988 Mar;91(3):445–466. doi: 10.1085/jgp.91.3.445. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Sheu S. S., Fozzard H. A. Transmembrane Na+ and Ca2+ electrochemical gradients in cardiac muscle and their relationship to force development. J Gen Physiol. 1982 Sep;80(3):325–351. doi: 10.1085/jgp.80.3.325. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Soejima M., Noma A. Mode of regulation of the ACh-sensitive K-channel by the muscarinic receptor in rabbit atrial cells. Pflugers Arch. 1984 Apr;400(4):424–431. doi: 10.1007/BF00587544. [DOI] [PubMed] [Google Scholar]
  27. Stimers J. R., Lobaugh L. A., Liu S., Shigeto N., Lieberman M. Intracellular sodium affects ouabain interaction with the Na/K pump in cultured chick cardiac myocytes. J Gen Physiol. 1990 Jan;95(1):77–95. doi: 10.1085/jgp.95.1.77. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Stimers J. R., Shigeto N., Lieberman M. Na/K pump current in aggregates of cultured chick cardiac myocytes. J Gen Physiol. 1990 Jan;95(1):61–76. doi: 10.1085/jgp.95.1.61. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Yamagishi S., Sano T. Effect of temperature on pacemaker activity of rabbit sinus node. Am J Physiol. 1967 Apr;212(4):829–834. doi: 10.1152/ajplegacy.1967.212.4.829. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES