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Kappl M, Nagel G, Hartung K. Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps. Biophys J. 2001;81(5):2628-38doi: 10.1016/S0006-3495(01)75906-1.
Kappl, M., Nagel, G., & Hartung, K. (2001). Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps. Biophysical journal, 81(5), 2628-38. https://doi.org/10.1016/S0006-3495(01)75906-1
Kappl, M, et al. "Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps." Biophysical journal vol. 81,5 (2001): 2628-38. doi: https://doi.org/10.1016/S0006-3495(01)75906-1
Kappl M, Nagel G, Hartung K. Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps. Biophys J. 2001 Nov;81(5):2628-38. doi: 10.1016/S0006-3495(01)75906-1. PMID: 11606276; PMCID: PMC1301730.
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Biophys J. 2001 Nov;81(5):2628-38. doi: 10.1016/S0006-3495(01)75906-1.

Voltage and Ca(2+) dependence of pre-steady-state currents of the Na-Ca exchanger generated by Ca(2+) concentration jumps.

Biophysical journal

M Kappl, G Nagel, K Hartung

Affiliations

  1. Max-Planck-Institut für Biophysik, D-60596 Frankfurt, Germany.

PMID: 11606276 PMCID: PMC1301730 DOI: 10.1016/S0006-3495(01)75906-1

Abstract

The Ca(2+) concentration and voltage dependence of the relaxation kinetics of the Na-Ca exchanger after a Ca(2+) concentration jump was measured in excised giant membrane patches from guinea pig heart. Ca(2+) concentration jumps on the cytoplasmic side were achieved by laser flash-induced photolysis of DM-nitrophen. In the Ca-Ca exchange mode a transient inward current is generated. The amplitude and the decay rate of the current saturate at concentrations >10 microM. The integrated current signal, i.e., the charge moved is fairly independent of the amount of Ca(2+) released. The amount of charge translocated increases at negative membrane potentials, whereas the decay rate constant shows no voltage dependence. It is suggested that Ca(2+) translocation occurs in at least four steps: intra- and extracellular Ca(2+) binding and two intramolecular transport steps. Saturation of the amplitude and of the relaxation of the current can be explained if the charge translocating reaction step is preceded by two nonelectrogenic steps: Ca(2+) binding and one conformational transition. Charge translocation in this mode is assigned to one additional conformational change which determines the equilibrium distribution of states. In the Na-Ca exchange mode, the stationary inward current depends on the cytoplasmic Ca(2+) concentration and voltage. The K(m) for Ca(2+) is 4 microM for guinea pig and 10 microM for rat myocytes. The amplitude of the pre-steady-state current and its relaxation saturate with increasing Ca(2+) concentrations. In this mode the relaxation is voltage dependent.

References

  1. J Membr Biol. 1975 Jul 24;22(3-4):285-312 - PubMed
  2. Physiol Rev. 1999 Jul;79(3):763-854 - PubMed
  3. J Biol Chem. 1983 Mar 10;258(5):3183-90 - PubMed
  4. Nature. 1986 Feb 13-19;319(6054):596-7 - PubMed
  5. Nature. 1986 Feb 13-19;319(6054):597-9 - PubMed
  6. J Gen Physiol. 1987 Oct;90(4):505-25 - PubMed
  7. J Membr Biol. 1987;99(1):1-11 - PubMed
  8. Proc Natl Acad Sci U S A. 1988 Sep;85(17):6571-5 - PubMed
  9. Pflugers Arch. 1989 Nov;415(2):247-9 - PubMed
  10. Nature. 1990 Mar 15;344(6263):242-5 - PubMed
  11. J Gen Physiol. 1990 May;95(5):819-35 - PubMed
  12. Nature. 1991 Feb 14;349(6310):621-4 - PubMed
  13. Nature. 1991 Aug 22;352(6337):715-8 - PubMed
  14. Biochemistry. 1992 Sep 22;31(37):8856-61 - PubMed
  15. J Gen Physiol. 1992 Dec;100(6):963-1001 - PubMed
  16. Cell Calcium. 1993 Feb;14(2):87-100 - PubMed
  17. Biophys J. 1993 Aug;65(2):882-91 - PubMed
  18. J Physiol. 1993 Dec;472:45-53 - PubMed
  19. Biophys J. 1996 Feb;70(2):1006-16 - PubMed
  20. Biophys J. 1996 Aug;71(2):759-68 - PubMed
  21. Biophys J. 1996 Nov;71(5):2473-85 - PubMed
  22. J Gen Physiol. 1998 Jun;111(6):857-73 - PubMed
  23. J Biol Chem. 1980 Oct 25;255(20):9626-34 - PubMed

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