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. 1987 Aug;389:205–222. doi: 10.1113/jphysiol.1987.sp016654

An intrinsic potential-dependent inactivation mechanism associated with calcium channels in guinea-pig myocytes.

R W Hadley 1, J R Hume 1
PMCID: PMC1192078  PMID: 2445973

Abstract

1. Currents through Ca2+ channels of single guinea-pig ventricular myocytes were studied using patch electrodes for whole-cell recording. Currents through Na+ and K+ channels were suppressed by the application of drugs or the substitution of impermeant ions. 2. Inactivation of the Ca2+ current (ICa) was investigated using a two-pulse protocol. The amount of inactivation left behind by a pre-pulse appeared to be related to current magnitude, as others have reported. The dependence of inactivation on the pre-pulse potential was partially U-shaped, as the amount of inactivation peaked at 0 mV and then declined with more positive pre-pulses. 3. Non-specific current carried by monovalent ions through Ca2+ channels (Ins) was induced by lowering the extracellular Ca2+ concentration with EGTA. Ins peaked in an inward direction at -20 mV, reversed direction at +22 mV, and became a large outward current at more positive potentials. 4. Ins inactivated with a slow time course. The inactivation was not due to accumulation or depletion phenomena. Studies using two-pulse protocols showed that the amount of inactivation left by a pre-pulse was directly related to the pre-pulse potential. 5. The addition of micromolar amounts of free Ca2+ to the external solution induced outward rectification of Ins. Inward currents were small or absent, while larger outward currents could still be seen at very positive potentials. Ca2+-channel inactivation still occurred under these conditions, even in the absence of any significant ionic movement. 6. The time courses of Ins inactivation and recovery were studied. The half-time of Ins inactivation decreased with larger depolarizations. Recovery of Ins was very slow, but could be accounted for by changes in the surface charge of the membrane. 7. It is concluded that Ins inactivation is due solely to a voltage-dependent inactivation process which is intrinsic to myocardial Ca2+ channels. Voltage-dependent inactivation appears to account for a significant proportion of total Ca2+-channel inactivation at negative potentials, and appears to account for almost all of the inactivation at very positive potentials, even in the presence of millimolar concentration of external Ca2+.

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Selected References

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  1. Almers W., McCleskey E. W. Non-selective conductance in calcium channels of frog muscle: calcium selectivity in a single-file pore. J Physiol. 1984 Aug;353:585–608. doi: 10.1113/jphysiol.1984.sp015352. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Almers W., McCleskey E. W., Palade P. T. A non-selective cation conductance in frog muscle membrane blocked by micromolar external calcium ions. J Physiol. 1984 Aug;353:565–583. doi: 10.1113/jphysiol.1984.sp015351. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bean B. P. Two kinds of calcium channels in canine atrial cells. Differences in kinetics, selectivity, and pharmacology. J Gen Physiol. 1985 Jul;86(1):1–30. doi: 10.1085/jgp.86.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brehm P., Eckert R. Calcium entry leads to inactivation of calcium channel in Paramecium. Science. 1978 Dec 15;202(4373):1203–1206. doi: 10.1126/science.103199. [DOI] [PubMed] [Google Scholar]
  5. Brown A. M., Morimoto K., Tsuda Y., wilson D. L. Calcium current-dependent and voltage-dependent inactivation of calcium channels in Helix aspersa. J Physiol. 1981 Nov;320:193–218. doi: 10.1113/jphysiol.1981.sp013944. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Brown H. F., Kimura J., Noble D., Noble S. J., Taupignon A. The slow inward current, isi, in the rabbit sino-atrial node investigated by voltage clamp and computer simulation. Proc R Soc Lond B Biol Sci. 1984 Sep 22;222(1228):305–328. doi: 10.1098/rspb.1984.0066. [DOI] [PubMed] [Google Scholar]
  7. Eckert R., Chad J. E. Inactivation of Ca channels. Prog Biophys Mol Biol. 1984;44(3):215–267. doi: 10.1016/0079-6107(84)90009-9. [DOI] [PubMed] [Google Scholar]
  8. Ehrlich B. E., Schen C. R., Garcia M. L., Kaczorowski G. J. Incorporation of calcium channels from cardiac sarcolemmal membrane vesicles into planar lipid bilayers. Proc Natl Acad Sci U S A. 1986 Jan;83(1):193–197. doi: 10.1073/pnas.83.1.193. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Fox A. P. Voltage-dependent inactivation of a calcium channel. Proc Natl Acad Sci U S A. 1981 Feb;78(2):953–956. doi: 10.1073/pnas.78.2.953. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Fukushima Y., Hagiwara S. Currents carried by monovalent cations through calcium channels in mouse neoplastic B lymphocytes. J Physiol. 1985 Jan;358:255–284. doi: 10.1113/jphysiol.1985.sp015550. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. 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]
  12. Hess P., Tsien R. W. Mechanism of ion permeation through calcium channels. 1984 May 31-Jun 6Nature. 309(5967):453–456. doi: 10.1038/309453a0. [DOI] [PubMed] [Google Scholar]
  13. Hume J. R., Uehara A. "Creep currents" in single frog atrial cells may be generated by electrogenic Na/Ca exchange. J Gen Physiol. 1986 Jun;87(6):857–884. doi: 10.1085/jgp.87.6.857. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hume J. R., Uehara A. Ionic basis of the different action potential configurations of single guinea-pig atrial and ventricular myocytes. J Physiol. 1985 Nov;368:525–544. doi: 10.1113/jphysiol.1985.sp015874. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hume J. R., Uehara A. Properties of "creep currents" in single frog atrial cells. J Gen Physiol. 1986 Jun;87(6):833–855. doi: 10.1085/jgp.87.6.833. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Imoto Y., Ehara T., Goto M. Calcium channel currents in isolated guinea-pig ventricular cells superfused with Ca-free EGTA solution. Jpn J Physiol. 1985;35(6):917–932. doi: 10.2170/jjphysiol.35.917. [DOI] [PubMed] [Google Scholar]
  17. Isenberg G. Cardiac Purkinje fibers: cesium as a tool to block inward rectifying potassium currents. Pflugers Arch. 1976 Sep 30;365(2-3):99–106. doi: 10.1007/BF01067006. [DOI] [PubMed] [Google Scholar]
  18. Josephson I. R., Sanchez-Chapula J., Brown A. M. A comparison of calcium currents in rat and guinea pig single ventricular cells. Circ Res. 1984 Feb;54(2):144–156. doi: 10.1161/01.res.54.2.144. [DOI] [PubMed] [Google Scholar]
  19. Kass R. S., Sanguinetti M. C. Inactivation of calcium channel current in the calf cardiac Purkinje fiber. Evidence for voltage- and calcium-mediated mechanisms. J Gen Physiol. 1984 Nov;84(5):705–726. doi: 10.1085/jgp.84.5.705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Kass R. S., Scheuer T. Slow inactivation of calcium channels in the cardiac Purkinje fiber. J Mol Cell Cardiol. 1982 Oct;14(10):615–618. doi: 10.1016/0022-2828(82)90148-1. [DOI] [PubMed] [Google Scholar]
  21. Kimura J., Noma A., Irisawa H. Na-Ca exchange current in mammalian heart cells. Nature. 1986 Feb 13;319(6054):596–597. doi: 10.1038/319596a0. [DOI] [PubMed] [Google Scholar]
  22. Kohlhardt M., Krause H., Kübler M., Herdey A. Kinetics of inactivation and recovery of the slow inward current in the mammalian ventricular myocardium. Pflugers Arch. 1975 Mar 22;355(1):1–17. doi: 10.1007/BF00584795. [DOI] [PubMed] [Google Scholar]
  23. Lee K. S., Akaike N., Brown A. M. The suction pipette method for internal perfusion and voltage clamp of small excitable cells. J Neurosci Methods. 1980 Feb;2(1):51–78. doi: 10.1016/0165-0270(80)90045-x. [DOI] [PubMed] [Google Scholar]
  24. Lee K. S., Marban E., Tsien R. W. Inactivation of calcium channels in mammalian heart cells: joint dependence on membrane potential and intracellular calcium. J Physiol. 1985 Jul;364:395–411. doi: 10.1113/jphysiol.1985.sp015752. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Lee K. S., Noble D., Lee E., Spindler A. J. A new calcium current underlying the plateau of the cardiac action potential. Proc R Soc Lond B Biol Sci. 1984 Nov 22;223(1230):35–48. doi: 10.1098/rspb.1984.0081. [DOI] [PubMed] [Google Scholar]
  26. Lee K. S., Tsien R. W. High selectivity of calcium channels in single dialysed heart cells of the guinea-pig. J Physiol. 1984 Sep;354:253–272. doi: 10.1113/jphysiol.1984.sp015374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Lee K. S., Tsien R. W. Reversal of current through calcium channels in dialysed single heart cells. Nature. 1982 Jun 10;297(5866):498–501. doi: 10.1038/297498a0. [DOI] [PubMed] [Google Scholar]
  28. Marban E., Tsien R. W. Enhancement of calcium current during digitalis inotropy in mammalian heart: positive feed-back regulation by intracellular calcium? J Physiol. 1982 Aug;329:589–614. doi: 10.1113/jphysiol.1982.sp014321. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Matsuda H., Noma A. Isolation of calcium current and its sensitivity to monovalent cations in dialysed ventricular cells of guinea-pig. J Physiol. 1984 Dec;357:553–573. doi: 10.1113/jphysiol.1984.sp015517. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Mentrard D., Vassort G., Fischmeister R. Calcium-mediated inactivation of the calcium conductance in cesium-loaded frog heart cells. J Gen Physiol. 1984 Jan;83(1):105–131. doi: 10.1085/jgp.83.1.105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Mitchell M. R., Powell T., Terrar D. A., Twist V. W. Characteristics of the second inward current in cells isolated from rat ventricular muscle. Proc R Soc Lond B Biol Sci. 1983 Oct 22;219(1217):447–469. doi: 10.1098/rspb.1983.0084. [DOI] [PubMed] [Google Scholar]
  32. Nilius B., Hess P., Lansman J. B., Tsien R. W. A novel type of cardiac calcium channel in ventricular cells. Nature. 1985 Aug 1;316(6027):443–446. doi: 10.1038/316443a0. [DOI] [PubMed] [Google Scholar]
  33. Noble S., Shimoni Y. The calcium and frequency dependence of the slow inward current 'staircase' in frog atrium. J Physiol. 1981 Jan;310:57–75. doi: 10.1113/jphysiol.1981.sp013537. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Powell T., Twist V. W. A rapid technique for the isolation and purification of adult cardiac muscle cells having respiratory control and a tolerance to calcium. Biochem Biophys Res Commun. 1976 Sep 7;72(1):327–333. doi: 10.1016/0006-291x(76)90997-9. [DOI] [PubMed] [Google Scholar]
  35. Reuter H., Stevens C. F., Tsien R. W., Yellen G. Properties of single calcium channels in cardiac cell culture. Nature. 1982 Jun 10;297(5866):501–504. doi: 10.1038/297501a0. [DOI] [PubMed] [Google Scholar]
  36. Rosenberg R. L., Hess P., Reeves J. P., Smilowitz H., Tsien R. W. Calcium channels in planar lipid bilayers: insights into mechanisms of ion permeation and gating. Science. 1986 Mar 28;231(4745):1564–1566. doi: 10.1126/science.2420007. [DOI] [PubMed] [Google Scholar]
  37. Shimoni Y. Parameters affecting the slow inward channel repriming process in frog atrium. J Physiol. 1981 Nov;320:269–291. doi: 10.1113/jphysiol.1981.sp013948. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Tillotson D. Inactivation of Ca conductance dependent on entry of Ca ions in molluscan neurons. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1497–1500. doi: 10.1073/pnas.76.3.1497. [DOI] [PMC free article] [PubMed] [Google Scholar]

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