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An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state.

Publication ,  Journal Article
Hill, JA; Trantham, JL; Browning, DJ; Grant, AO; Strauss, HC
Published in: Can J Physiol Pharmacol
May 1986

We have estimated an upper limit for the electrogenic contribution of the Na-K pump to diastolic transmembrane potential. We simultaneously monitored the maximum diastolic potential and the extracellular space potassium activity during exposure to a very high concentration of ouabain. Exposure to ouabain caused a depolarization of approximately 3 mV (n = 33 experiments) over 34 +/- 3 s (mean +/- standard error) prior to any change in extracellular K activity. In four experiments, we monitored intracellular sodium activity and observed it to rise with approximately the same temporal lag (delay = 26 +/- 7 s). We also measured relative membrane conductance in one series of experiments and observed it to decrease to 91 +/- 2% of its control value by the time extracellular space K began to rise. Following the initial increase in extracellular space K activity the subsequent membrane depolarization is shown to be accurately predicted solely from the measured increase in extracellular space K activity as calculated from the Goldman equation. Limitations of the method and possible interpretations of the data are discussed. We interpret this ouabain-induced depolarization that occurs prior to the rise in external K to be an upper limit to the Na-K pump's electrogenic contribution to steady-state membrane potential.

Duke Scholars

Published In

Can J Physiol Pharmacol

DOI

ISSN

0008-4212

Publication Date

May 1986

Volume

64

Issue

5

Start / End Page

641 / 648

Location

Canada

Related Subject Headings

  • Sodium
  • Purkinje Fibers
  • Potassium
  • Physiology
  • Ouabain
  • Myocardial Contraction
  • Membranes
  • Ion Channels
  • Homeostasis
  • Heart Conduction System
 

Citation

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Hill, J. A., Trantham, J. L., Browning, D. J., Grant, A. O., & Strauss, H. C. (1986). An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state. Can J Physiol Pharmacol, 64(5), 641–648. https://doi.org/10.1139/y86-106
Hill, J. A., J. L. Trantham, D. J. Browning, A. O. Grant, and H. C. Strauss. “An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state.Can J Physiol Pharmacol 64, no. 5 (May 1986): 641–48. https://doi.org/10.1139/y86-106.
Hill JA, Trantham JL, Browning DJ, Grant AO, Strauss HC. An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state. Can J Physiol Pharmacol. 1986 May;64(5):641–8.
Hill, J. A., et al. “An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state.Can J Physiol Pharmacol, vol. 64, no. 5, May 1986, pp. 641–48. Pubmed, doi:10.1139/y86-106.
Hill JA, Trantham JL, Browning DJ, Grant AO, Strauss HC. An upper limit for the electrogenic Na-K pump contribution to maximum diastolic potential in feline cardiac Purkinje fibers in steady state. Can J Physiol Pharmacol. 1986 May;64(5):641–648.

Published In

Can J Physiol Pharmacol

DOI

ISSN

0008-4212

Publication Date

May 1986

Volume

64

Issue

5

Start / End Page

641 / 648

Location

Canada

Related Subject Headings

  • Sodium
  • Purkinje Fibers
  • Potassium
  • Physiology
  • Ouabain
  • Myocardial Contraction
  • Membranes
  • Ion Channels
  • Homeostasis
  • Heart Conduction System