Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1992 Aug;454:321–338. doi: 10.1113/jphysiol.1992.sp019266

Calcium transients caused by calcium entry are influenced by the sarcoplasmic reticulum in guinea-pig atrial myocytes.

P Lipp 1, L Pott 1, G Callewaert 1, E Carmeliet 1
PMCID: PMC1175607  PMID: 1335504

Abstract

1. Single atrial myocytes obtained by enzyme perfusion from hearts of adult guinea-pigs were investigated using whole-cell voltage clamp and Indo-1 micro-fluorometry. 2. In myocytes loaded with a solution containing citrate as a low-affinity, non-saturable Ca2+ chelator, two types of [Ca2+]i transients could be recorded during repetitive activation of L-type Ca2+ current. Both large and small [Ca2+]i transients occurred; large transients reached peak values of about 1 microM, and small transients were about 100 nM or less in amplitude. 3. In the case of the large transients, peak [Ca2+]i was usually reached with a variable delay after repolarization from a voltage step that activated calcium current (ICa). For the small transients the rise in [Ca2+]i paralleled ICa. Upon repolarization [Ca2+]i started to decay. 4. The small transients reflect entry of Ca2+ through Ca2+ channels (entry transients), whereas the large transients are due to entry and release from the sarcoplasmic reticulum (release transients). 5. The entry transients displayed a positive staircase pattern during trains of depolarizing voltage steps despite constant or even decreasing amplitude of ICa. The steepness of the staircase was increased by elevation of [Ca2+]o. Entry transients were always smallest immediately after a release transient. 6. After functional removal of the sarcoplasmic reticulum by caffeine (1-5 mM) the staircase pattern of the transients reflecting Ca2+ entry was abolished. 7. It is concluded that the staircase pattern is due to rapid uptake by the sarcoplasmic reticulum of Ca2+ entering the cell, resulting in an attenuation of the signal. The attenuation is strongest shortly after a release signal, when the rate of sequestration of Ca2+ by the SR should be highest. 8. Evidence is provided that a compartment of the SR is involved in attenuation of the entry transients. This compartment has been identified recently as a peripheral release compartment.

Full text

PDF
323

Selected References

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

  1. Bals S., Bechem M., Paffhausen W., Pott L. Spontaneous and experimentally evoked [Ca2+]i-transients in cardiac myocytes measured by means of a fast Fura-2 technique. Cell Calcium. 1990 Jun-Jul;11(6):385–396. doi: 10.1016/0143-4160(90)90050-5. [DOI] [PubMed] [Google Scholar]
  2. Barcenas-Ruiz L., Beuckelmann D. J., Wier W. G. Sodium-calcium exchange in heart: membrane currents and changes in [Ca2+]i. Science. 1987 Dec 18;238(4834):1720–1722. doi: 10.1126/science.3686010. [DOI] [PubMed] [Google Scholar]
  3. Bechem M., Pott L., Rennebaum H. Atrial muscle cells from hearts of adult guinea-pigs in culture: a new preparation for cardiac cellular electrophysiology. Eur J Cell Biol. 1983 Sep;31(2):366–369. [PubMed] [Google Scholar]
  4. Berlin J. R., Cannell M. B., Lederer W. J. Cellular origins of the transient inward current in cardiac myocytes. Role of fluctuations and waves of elevated intracellular calcium. Circ Res. 1989 Jul;65(1):115–126. doi: 10.1161/01.res.65.1.115. [DOI] [PubMed] [Google Scholar]
  5. Bers D. M. Ca influx and sarcoplasmic reticulum Ca release in cardiac muscle activation during postrest recovery. Am J Physiol. 1985 Mar;248(3 Pt 2):H366–H381. doi: 10.1152/ajpheart.1985.248.3.H366. [DOI] [PubMed] [Google Scholar]
  6. Beuckelmann D. J., Wier W. G. Mechanism of release of calcium from sarcoplasmic reticulum of guinea-pig cardiac cells. J Physiol. 1988 Nov;405:233–255. doi: 10.1113/jphysiol.1988.sp017331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Boller M., Pott L. Beta-adrenergic modulation of transient inward current in guinea-pig cardiac myocytes. Evidence for regulation of Ca2(+)-release from sarcoplasmic reticulum by a cyclic AMP dependent mechanism. Pflugers Arch. 1989 Dec;415(3):276–288. doi: 10.1007/BF00370877. [DOI] [PubMed] [Google Scholar]
  8. Budde T., Lipp P., Pott L. Measurement of Ca2(+)-release-dependent inward current reveals two distinct components of Ca2+ release from sarcoplasmic reticulum in guinea-pig atrial myocytes. Pflugers Arch. 1991 Feb;417(6):638–644. doi: 10.1007/BF00372963. [DOI] [PubMed] [Google Scholar]
  9. Callewaert G., Cleemann L., Morad M. Caffeine-induced Ca2+ release activates Ca2+ extrusion via Na+-Ca2+ exchanger in cardiac myocytes. Am J Physiol. 1989 Jul;257(1 Pt 1):C147–C152. doi: 10.1152/ajpcell.1989.257.1.C147. [DOI] [PubMed] [Google Scholar]
  10. Callewaert G., Cleemann L., Morad M. Epinephrine enhances Ca2+ current-regulated Ca2+ release and Ca2+ reuptake in rat ventricular myocytes. Proc Natl Acad Sci U S A. 1988 Mar;85(6):2009–2013. doi: 10.1073/pnas.85.6.2009. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Callewaert G., Lipp P., Pott L., Carmeliet E. High-resolution measurement and calibration of Ca(2+)-transients using Indo-1 in guinea-pig atrial myocytes under voltage clamp. Cell Calcium. 1991 Apr;12(4):269–277. doi: 10.1016/0143-4160(91)90001-u. [DOI] [PubMed] [Google Scholar]
  12. Carafoli E. The homeostasis of calcium in heart cells. J Mol Cell Cardiol. 1985 Mar;17(3):203–212. doi: 10.1016/s0022-2828(85)80003-1. [DOI] [PubMed] [Google Scholar]
  13. Earm Y. E., Noble D. A model of the single atrial cell: relation between calcium current and calcium release. Proc R Soc Lond B Biol Sci. 1990 May 22;240(1297):83–96. doi: 10.1098/rspb.1990.0028. [DOI] [PubMed] [Google Scholar]
  14. Eisner D. A. The Wellcome prize lecture. Intracellular sodium in cardiac muscle: effects on contraction. Exp Physiol. 1990 Jul;75(4):437–457. doi: 10.1113/expphysiol.1990.sp003422. [DOI] [PubMed] [Google Scholar]
  15. Fabiato A. Simulated calcium current can both cause calcium loading in and trigger calcium release from the sarcoplasmic reticulum of a skinned canine cardiac Purkinje cell. J Gen Physiol. 1985 Feb;85(2):291–320. doi: 10.1085/jgp.85.2.291. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Fabiato A. Time and calcium dependence of activation and inactivation of calcium-induced release of calcium from the sarcoplasmic reticulum of a skinned canine cardiac Purkinje cell. J Gen Physiol. 1985 Feb;85(2):247–289. doi: 10.1085/jgp.85.2.247. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Frampton J. E., Orchard C. H., Boyett M. R. Diastolic, systolic and sarcoplasmic reticulum [Ca2+] during inotropic interventions in isolated rat myocytes. J Physiol. 1991 Jun;437:351–375. doi: 10.1113/jphysiol.1991.sp018600. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Grynkiewicz G., Poenie M., Tsien R. Y. A new generation of Ca2+ indicators with greatly improved fluorescence properties. J Biol Chem. 1985 Mar 25;260(6):3440–3450. [PubMed] [Google Scholar]
  19. 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]
  20. Ishide N., Urayama T., Inoue K., Komaru T., Takishima T. Propagation and collision characteristics of calcium waves in rat myocytes. Am J Physiol. 1990 Sep;259(3 Pt 2):H940–H950. doi: 10.1152/ajpheart.1990.259.3.H940. [DOI] [PubMed] [Google Scholar]
  21. KOCH-WESER J., BLINKS J. R. THE INFLUENCE OF THE INTERVAL BETWEEN BEATS ON MYOCARDIAL CONTRACTILITY. Pharmacol Rev. 1963 Sep;15:601–652. [PubMed] [Google Scholar]
  22. Leblanc N., Hume J. R. Sodium current-induced release of calcium from cardiac sarcoplasmic reticulum. Science. 1990 Apr 20;248(4953):372–376. doi: 10.1126/science.2158146. [DOI] [PubMed] [Google Scholar]
  23. Li Q., Altschuld R. A., Stokes B. T. Quantitation of intracellular free calcium in single adult cardiomyocytes by fura-2 fluorescence microscopy: calibration of fura-2 ratios. Biochem Biophys Res Commun. 1987 Aug 31;147(1):120–126. doi: 10.1016/s0006-291x(87)80095-5. [DOI] [PubMed] [Google Scholar]
  24. Lipp P., Mechmann S., Pott L. Effects of calcium release from sarcoplasmic reticulum on membrane currents in guinea pig atrial cardioballs. Pflugers Arch. 1987 Sep;410(1-2):121–131. doi: 10.1007/BF00581904. [DOI] [PubMed] [Google Scholar]
  25. Lipp P., Pott L., Callewaert G., Carmeliet E. Simultaneous recording of Indo-1 fluorescence and Na+/Ca2+ exchange current reveals two components of Ca2(+)-release from sarcoplasmic reticulum of cardiac atrial myocytes. FEBS Lett. 1990 Nov 26;275(1-2):181–184. doi: 10.1016/0014-5793(90)81467-3. [DOI] [PubMed] [Google Scholar]
  26. Lipp P., Pott L. Effects of intracellular Ca2+ chelating compounds on inward currents caused by Ca2+ release from sarcoplasmic reticulum in guinea-pig atrial myocytes. Pflugers Arch. 1991 Oct;419(3-4):296–303. doi: 10.1007/BF00371110. [DOI] [PubMed] [Google Scholar]
  27. Lipp P., Pott L. Transient inward current in guinea-pig atrial myocytes reflects a change of sodium-calcium exchange current. J Physiol. 1988 Mar;397:601–630. doi: 10.1113/jphysiol.1988.sp017021. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Lipp P., Pott L. Voltage dependence of sodium-calcium exchange current in guinea-pig atrial myocytes determined by means of an inhibitor. J Physiol. 1988 Sep;403:355–366. doi: 10.1113/jphysiol.1988.sp017253. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Mechmann S., Pott L. Identification of Na-Ca exchange current in single cardiac myocytes. Nature. 1986 Feb 13;319(6054):597–599. doi: 10.1038/319597a0. [DOI] [PubMed] [Google Scholar]
  30. Miura Y., Kimura J. Sodium-calcium exchange current. Dependence on internal Ca and Na and competitive binding of external Na and Ca. J Gen Physiol. 1989 Jun;93(6):1129–1145. doi: 10.1085/jgp.93.6.1129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Näbauer M., Callewaert G., Cleemann L., Morad M. Regulation of calcium release is gated by calcium current, not gating charge, in cardiac myocytes. Science. 1989 May 19;244(4906):800–803. doi: 10.1126/science.2543067. [DOI] [PubMed] [Google Scholar]
  32. O'Neill S. C., Donoso P., Eisner D. A. The role of [Ca2+]i and [Ca2+] sensitization in the caffeine contracture of rat myocytes: measurement of [Ca2+]i and [caffeine]i. J Physiol. 1990 Jun;425:55–70. doi: 10.1113/jphysiol.1990.sp018092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Pott L., Mechmann S. Large-conductance ion channel measured by whole-cell voltage clamp in single cardiac cells: modulation by beta-adrenergic stimulation and inhibition by octanol. J Membr Biol. 1990 Aug;117(2):189–199. doi: 10.1007/BF01868685. [DOI] [PubMed] [Google Scholar]
  34. Reiter M. Calcium mobilization and cardiac inotropic mechanisms. Pharmacol Rev. 1988 Sep;40(3):189–217. [PubMed] [Google Scholar]
  35. Rousseau E., Meissner G. Single cardiac sarcoplasmic reticulum Ca2+-release channel: activation by caffeine. Am J Physiol. 1989 Feb;256(2 Pt 2):H328–H333. doi: 10.1152/ajpheart.1989.256.2.H328. [DOI] [PubMed] [Google Scholar]
  36. Sipido K. R., Wier W. G. Flux of Ca2+ across the sarcoplasmic reticulum of guinea-pig cardiac cells during excitation-contraction coupling. J Physiol. 1991 Apr;435:605–630. doi: 10.1113/jphysiol.1991.sp018528. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Sitsapesan R., Williams A. J. Mechanisms of caffeine activation of single calcium-release channels of sheep cardiac sarcoplasmic reticulum. J Physiol. 1990 Apr;423:425–439. doi: 10.1113/jphysiol.1990.sp018031. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Spurgeon H. A., Stern M. D., Baartz G., Raffaeli S., Hansford R. G., Talo A., Lakatta E. G., Capogrossi M. C. Simultaneous measurement of Ca2+, contraction, and potential in cardiac myocytes. Am J Physiol. 1990 Feb;258(2 Pt 2):H574–H586. doi: 10.1152/ajpheart.1990.258.2.H574. [DOI] [PubMed] [Google Scholar]
  39. Takamatsu T., Wier W. G. Calcium waves in mammalian heart: quantification of origin, magnitude, waveform, and velocity. FASEB J. 1990 Mar;4(5):1519–1525. doi: 10.1096/fasebj.4.5.2307330. [DOI] [PubMed] [Google Scholar]
  40. Valdeolmillos M., O'Neill S. C., Smith G. L., Eisner D. A. Calcium-induced calcium release activates contraction in intact cardiac cells. Pflugers Arch. 1989 Apr;413(6):676–678. doi: 10.1007/BF00581820. [DOI] [PubMed] [Google Scholar]
  41. Weber A., Herz R. The relationship between caffeine contracture of intact muscle and the effect of caffeine on reticulum. J Gen Physiol. 1968 Nov;52(5):750–759. doi: 10.1085/jgp.52.5.750. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Wier W. G. Cytoplasmic [Ca2+] in mammalian ventricle: dynamic control by cellular processes. Annu Rev Physiol. 1990;52:467–485. doi: 10.1146/annurev.ph.52.030190.002343. [DOI] [PubMed] [Google Scholar]
  43. duBell W. H., Houser S. R. Voltage and beat dependence of Ca2+ transient in feline ventricular myocytes. Am J Physiol. 1989 Sep;257(3 Pt 2):H746–H759. doi: 10.1152/ajpheart.1989.257.3.H746. [DOI] [PubMed] [Google Scholar]

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

RESOURCES