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Coupled sodium-calcium transport in cultured chick heart cells.

Publication ,  Journal Article
Murphy, E; Wheeler, DM; LeFurgey, A; Jacob, R; Lobaugh, LA; Lieberman, M
Published in: Am J Physiol
March 1986

In cultured embryonic chick heart cells, alterations of extracellular Na (Nao) and Ca (Cao), intracellular Na (Nai) and Ca, extracellular pH, and membrane potential resulted in changes in Na and Ca contents that were consistent with sarcolemmal Na-Ca exchange. 24Na efflux measurements revealed a large ouabain-insensitive component, one-third of which was inhibited by removal of Cao. Incubating the cells in Na-free solution resulted in a rapid, 1.5- to 2-fold increase in total cell Ca that remained elevated for at least 15 min. Cells exposed for 15 min to Nao less than or equal to 20 mM became maximally loaded with Ca, whereas Ca loading fell off sharply at values of Nao greater than 20 mM. The movement of Na against its electrochemical gradient was shown to be associated with Ca accumulation. During Na-K pump inhibition (in 10(-4) M ouabain), Na initially rose 2- to 3-fold to a level below its equilibrium value; then, lowering Cao for 30 min from 1.25 to 0.75 mM caused a 26% elevation in Nai, whereas raising Cao from 1.25 to 2.7 mM resulted in a 25% fall in Nai against its electrochemical gradient. These data are consistent with Nai being maintained by a Na-Ca exchange during Na-K pump inhibition. In the presence of ouabain (10(-4) M), Ca uptake into intracellular organelles, e.g., mitochondria, was suggested by an increase in total cell Ca as well as the occurrence of mitochondrial matrix granules, which were shown qualitatively by X-ray analysis to contain Ca. Although matrix granules also occurred in mitochondria during Na-free incubation, they did not contain detectable amounts of Ca when examined under identical conditions of fixation and analysis.

Duke Scholars

Published In

Am J Physiol

DOI

ISSN

0002-9513

Publication Date

March 1986

Volume

250

Issue

3 Pt 1

Start / End Page

C442 / C452

Location

United States

Related Subject Headings

  • Sodium
  • Sarcolemma
  • Ouabain
  • Myocardium
  • Myocardial Contraction
  • Mitochondria, Heart
  • Microscopy, Electron
  • Membrane Potentials
  • Ion Channels
  • Hydrogen-Ion Concentration
 

Citation

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MLA
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Murphy, E., Wheeler, D. M., LeFurgey, A., Jacob, R., Lobaugh, L. A., & Lieberman, M. (1986). Coupled sodium-calcium transport in cultured chick heart cells. Am J Physiol, 250(3 Pt 1), C442–C452. https://doi.org/10.1152/ajpcell.1986.250.3.C442
Murphy, E., D. M. Wheeler, A. LeFurgey, R. Jacob, L. A. Lobaugh, and M. Lieberman. “Coupled sodium-calcium transport in cultured chick heart cells.Am J Physiol 250, no. 3 Pt 1 (March 1986): C442–52. https://doi.org/10.1152/ajpcell.1986.250.3.C442.
Murphy E, Wheeler DM, LeFurgey A, Jacob R, Lobaugh LA, Lieberman M. Coupled sodium-calcium transport in cultured chick heart cells. Am J Physiol. 1986 Mar;250(3 Pt 1):C442–52.
Murphy, E., et al. “Coupled sodium-calcium transport in cultured chick heart cells.Am J Physiol, vol. 250, no. 3 Pt 1, Mar. 1986, pp. C442–52. Pubmed, doi:10.1152/ajpcell.1986.250.3.C442.
Murphy E, Wheeler DM, LeFurgey A, Jacob R, Lobaugh LA, Lieberman M. Coupled sodium-calcium transport in cultured chick heart cells. Am J Physiol. 1986 Mar;250(3 Pt 1):C442–C452.

Published In

Am J Physiol

DOI

ISSN

0002-9513

Publication Date

March 1986

Volume

250

Issue

3 Pt 1

Start / End Page

C442 / C452

Location

United States

Related Subject Headings

  • Sodium
  • Sarcolemma
  • Ouabain
  • Myocardium
  • Myocardial Contraction
  • Mitochondria, Heart
  • Microscopy, Electron
  • Membrane Potentials
  • Ion Channels
  • Hydrogen-Ion Concentration