ELEVATED extracellular Ca2+ concentration1, prolonged treatment with high doses of cardiac glycosides2, and metabolic inhibition3 shorten the action potential of cardiac muscle. In these conditions the intracellular free Ca2+ may be increased and an increase in intracellular Ca2+ could produce shortening of the action potential either by affecting the Ca2+ inward current or by increasing the potassium permeability4. The latter mechanism has been observed in red blood cells5 and in the neurones of some species6–8. Here I give the results of studying the effect of iontophoretically injected Ca2+ in cardiac Purkinje cells. Such injection led to membrane hyperpolarisation and considerable shortening of the action potential, suggesting that the level of intracellular free Ca2+ can affect the potassium permeability in cardiac muscle.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Get just this article for as long as you need it
Prices may be subject to local taxes which are calculated during checkout
Temte, J. V., and Davis, L. D. D., Circulation Res., 20, 32–45 (1967).
Dudel, J., and Trautwein, W., Archs exp. Path. Pharmac., 232, 393–407 (1958).
McDonald, T. F., and MacLeod, D. P., J. Physiol., Lond., 229, 583–599 (1973).
Trautwein, W., Physiol. Rev., 53, 793–835 (1973).
Whittam, R., Nature, 219, 610 (1968).
Meech, R. W., Comp. Biochem. Physiol., 42A, 493–499 (1972).
Meech, R. W., J. Physiol., Lond., 237, 259–274 (1974).
Krnjevic, K., and Liesewicz, W., J. Physiol., Lond., 225, 363–390 (1972).
Kushmerick, M. J., and Podolsky, R. J., Science, 166, 1297–1298 (1969).
Dreyer, F., and Peper, K., Pflügers Archs ges. Physiol., 348, 263–272 (1972).
Rights and permissions
About this article
Cite this article
ISENBERG, G. Is potassium conductance of cardiac Purkinje fibres controlled by [Ca2+]i?. Nature 253, 273–274 (1975). https://doi.org/10.1038/253273a0
This article is cited by
Taurine modulates IKr but not IKs in guinea-pig ventricular cardiomyocytes
British Journal of Pharmacology (1999)
A dual action of taurine on the delayed rectifier K+ current in embryonic chick cardiomyocytes
Amino Acids (1995)
Alterations of ionic currents after reoxygenation in isolated cardiocytes of guinea-pigs
Pfl�gers Archiv European Journal of Physiology (1991)
Currents through ionic channels in multicellular cardiac tissue and single heart cells
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.