Skip to main content
PMC home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1978 Jan 1;71(1):47–67. doi: 10.1085/jgp.71.1.47

On the effects of divalent cations and ethylene glycol-bis-(beta- aminoethyl ether) N,N,N',N'-tetraacetate on action potential duration in frog heart

PMCID: PMC2215102  PMID: 23408

Abstract

Resting and action potentials were recorded from superfused strips of frog ventricle. Reducing the bathing calcium concentration ([Ca2+]0) with or without ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'- tetraacetate (EGTA) prolongs the action potential (AP). The change in the duration of the AP extends over many minutes, but is rapidly reversed by restoring calcium ions. Other changes (e.g., in resting potential and overshoot) are, however, only more slowly reversed. Reducing [Ca2+]0 with 0.2, 2, or 5 mM EGTA produces progressively greater prolongation of AP; maximum values were well in excess of 1 min. This prolongation can be reversed by other divalent cations in EGTA (Mg2+, Sr2+) or Ca-free (Mn2+) solutions, or by acetylcholine. Barium ions increase AP duration in keeping with their known effect on potassium conductance. D600, which blocks the slow inward current in cardiac muscle, is without effect on the action potentials recorded in EGTA solutions, or on the time course and extent of the recovery to normal duration upon restoring calcium ions. It is concluded that divalent cations exert an influence on membrane potassium conductance extracellularly in frog heart. The cell membrane does not become excessively "leaky" in EGTA solutions.

Full Text

The Full Text of this article is available as a PDF (1.4 MB).

Selected References

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

  1. CHANG J. J., SCHMIDT R. F. Prolonged action potentials and regenerative hyperpolarizing responses in Purkinje fibers of mammalian heart. Pflugers Arch Gesamte Physiol Menschen Tiere. 1960;272:127–141. doi: 10.1007/BF00420020. [DOI] [PubMed] [Google Scholar]
  2. Chapman R. A., Miller D. J. The effects of caffeine on the contraction of the frog heart. J Physiol. 1974 Nov;242(3):589–613. doi: 10.1113/jphysiol.1974.sp010725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Chapman R. A., Niedergerke R. Effects of calcium on the contraction of the hypodynamic frog heart. J Physiol. 1970 Dec;211(2):389–421. doi: 10.1113/jphysiol.1970.sp009284. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Chapman R. A., Tunstall J. The dependence of the contractile force generated by frog auricular trabeculae upon the external calcium concentration. J Physiol. 1971 May;215(1):139–162. doi: 10.1113/jphysiol.1971.sp009462. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chesnais J. M., Coraboeuf E., Sauviat M. P., Vassas J. M. Sensitivity to H, Li and Mg ions of the slow inward sodium current in frog atrial fibres. J Mol Cell Cardiol. 1975 Sep;7(9):627–642. doi: 10.1016/0022-2828(75)90140-6. [DOI] [PubMed] [Google Scholar]
  6. Cleemann L., Morad M. Extracellular potassium accumulation and inward-going potassium rectification in voltage clamped ventricular muscle. Science. 1976 Jan 9;191(4222):90–92. doi: 10.1126/science.1246599. [DOI] [PubMed] [Google Scholar]
  7. Daly I. de B., Clark A. J. The action of ions upon the frog's heart. J Physiol. 1921 Mar 15;54(5-6):367–383. doi: 10.1113/jphysiol.1921.sp001938. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Einwächter H. M., Haas H. G., Kern R. Membrane current and contraction in frog atrial fibres. J Physiol. 1972 Dec;227(1):141–171. doi: 10.1113/jphysiol.1972.sp010024. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. FRANKENHAEUSER B., HODGKIN A. L. The action of calcium on the electrical properties of squid axons. J Physiol. 1957 Jul 11;137(2):218–244. doi: 10.1113/jphysiol.1957.sp005808. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Giles W., Noble S. J. Changes in membrane currents in bullfrog atrium produced by acetylcholine. J Physiol. 1976 Sep;261(1):103–123. doi: 10.1113/jphysiol.1976.sp011550. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. HOFFMAN B. F., SUCKLING E. E. Effect of several cations on transmembrane potentials of cardiac muscle. Am J Physiol. 1956 Aug;186(2):317–324. doi: 10.1152/ajplegacy.1956.186.2.317. [DOI] [PubMed] [Google Scholar]
  12. Juncker D. F., Greene E. A., Stish R., Lorber V. Potassium efflux from amphibian atrium during the cardiac cycle. A reexamination. Circ Res. 1972 Mar;30(3):350–357. doi: 10.1161/01.res.30.3.350. [DOI] [PubMed] [Google Scholar]
  13. Kass R. S., Tsien R. W. Control of action potential duration by calcium ions in cardiac Purkinje fibers. J Gen Physiol. 1976 May;67(5):599–617. doi: 10.1085/jgp.67.5.599. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Kass R. S., Tsien R. W. Multiple effects of calcium antagonists on plateau currents in cardiac Purkinje fibers. J Gen Physiol. 1975 Aug;66(2):169–192. doi: 10.1085/jgp.66.2.169. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kohlhardt M., Bauer B., Krause H., Fleckenstein A. Differentiation of the transmembrane Na and Ca channels in mammalian cardiac fibres by the use of specific inhibitors. Pflugers Arch. 1972;335(4):309–322. doi: 10.1007/BF00586221. [DOI] [PubMed] [Google Scholar]
  16. Kohlhardt M., Haastert H. P., Krause H. Evidence of non-specificity of the Ca channel in mammalian myocardial fibre membranes. Substitution of Ca by Sr, Ba or Mg as charge carriers. Pflugers Arch. 1973 Aug 17;342(2):125–136. doi: 10.1007/BF00587843. [DOI] [PubMed] [Google Scholar]
  17. Kohlhardt M., Herdey A., Kübler M. Interchangeability of Ca ions and Sr ions as charge carriers of the slow inward current in mammalian myocardial fibres. Pflugers Arch. 1973 Nov 26;344(2):149–158. doi: 10.1007/BF00586548. [DOI] [PubMed] [Google Scholar]
  18. Lew V. L., Ferreira H. G. Variable Ca sensitivity of a K-selective channel in intact red-cell membranes. Nature. 1976 Sep 23;263(5575):336–338. doi: 10.1038/263336a0. [DOI] [PubMed] [Google Scholar]
  19. Meech R. W., Standen N. B. Potassium activation in Helix aspersa neurones under voltage clamp: a component mediated by calcium influx. J Physiol. 1975 Jul;249(2):211–239. doi: 10.1113/jphysiol.1975.sp011012. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Meech R. W. The sensitivity of Helix aspersa neurones to injected calcium ions. J Physiol. 1974 Mar;237(2):259–277. doi: 10.1113/jphysiol.1974.sp010481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Miller D. J., Moisescu D. G. The effects of very low external calcium and sodium concentrations on cardiac contractile strength and calcium-sodium antagonism. J Physiol. 1976 Jul;259(2):283–308. doi: 10.1113/jphysiol.1976.sp011466. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Mines G. R. On functional analysis by the action of electrolytes. J Physiol. 1913 Jun 19;46(3):188–235. doi: 10.1113/jphysiol.1913.sp001588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Narahashi T. Chemicals as tools in the study of excitable membranes. Physiol Rev. 1974 Oct;54(4):813–889. doi: 10.1152/physrev.1974.54.4.813. [DOI] [PubMed] [Google Scholar]
  24. Niedergerke R., Orkand R. K. The dual effect of calcium on the action potential of the frog's heart. J Physiol. 1966 May;184(2):291–311. doi: 10.1113/jphysiol.1966.sp007916. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Ochi R. Manganese action potentials in mammalian cardiac muscle. Experientia. 1975 Sep 15;31(9):1048–1049. doi: 10.1007/BF02326952. [DOI] [PubMed] [Google Scholar]
  26. Page S. G., Niedergerke R. Structures of physiological interest in the frog heart ventricle. J Cell Sci. 1972 Jul;11(1):179–203. doi: 10.1242/jcs.11.1.179. [DOI] [PubMed] [Google Scholar]
  27. Polimeni P. I., Page E. Magnesium in heart muscle. Circ Res. 1973 Oct 5;33(4):367–374. doi: 10.1161/01.res.33.4.367. [DOI] [PubMed] [Google Scholar]
  28. Rougier O., Vassort G., Garnier D., Gargouil Y. M., Coraboeuf E. Existence and role of a slow inward current during the frog atrial action potential. Pflugers Arch. 1969;308(2):91–110. doi: 10.1007/BF00587018. [DOI] [PubMed] [Google Scholar]
  29. Ten Eick R., Nawrath H., McDonald T. F., Trautwein W. On the mechanism of the negative inotropic effect of acetylcholine. Pflugers Arch. 1976 Feb 24;361(3):207–213. doi: 10.1007/BF00587284. [DOI] [PubMed] [Google Scholar]
  30. Tritthart H., MacLeod D. P., Stierle H. E., Krause H. Effects of Ca-free and EDTA-containing tyrode solution on transmembrane electrical activity and contraction in guinea pig papillary muscle. Pflugers Arch. 1973;338(4):361–376. doi: 10.1007/BF00586077. [DOI] [PubMed] [Google Scholar]
  31. Ueno A. Further evidence for negative inotropic action of acetylcholine. Jpn J Pharmacol. 1973 Jun;23(3):299–306. doi: 10.1254/jjp.23.299. [DOI] [PubMed] [Google Scholar]
  32. Winegrad S. Studies of cardiac muscle with a high permeability to calcium produced by treatment with ethylenediaminetetraacetic acid. J Gen Physiol. 1971 Jul;58(1):71–93. doi: 10.1085/jgp.58.1.71. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES