Summary
Inward-rectifier channels in cardiac cells (I K1) stabilize the resting membrane potential near the K equilibrium potential. Here we investigate the role ofI K1 in the regulation of action potentials and link this to the influx of Ca during beating. Inward Ca current alters the open-channel probability of outwardI K1 current. Thus Ca ions depolarize cells not only by carrying an inward current but also by blocking an outward current.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
DeHaan, R.L. 1967. Regulation of spontaneous activity and growth of embryonic chick heart cells in culture.Dev. Biol. 16:216–249
Duchatelle-Gourdon, I., Hartzell, H.C., LaGrutta, A.A. 1989. Modulation of the delayed rectifier K current in frog cardiomyocytes by β-adrenergic agonists and Mg.J. Physiol. (London) 415:251–274
Kameyama, M., Kiyosue, T., Soejima, M. 1983. Single channel analysis of the inward rectifier K current in the rabbit ventricular cells.Jpn. J. Physiol. 33:1039–1056
Kell, M.J., DeFelice, L.J. 1988. Surface charge near the cardiac inward-rectifier channel measured from single-channel conductance.J. Membrane Biol. 102:1–10
Kurachi, Y. 1985. Voltage dependent activation of the inward rectifier K channel in the ventricular cell membrane of guinea-pig heart.J. Physiol. (London) 366:365–385
Matsuda, H. 1988. Open state substructure of inwardly rectifying K channels revealed by Mg block in guinea-pig heart cells.J. Physiol. (London) 397:237–258
Matsuda, H. Saigusa, A., Irisawa, H. 1987. Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg++ Nature (London) 325:156–159
Mazzanti, M., DeFelice, L.J. 1987. Na channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells.Biophys. J. 52:95–100
Mazzanti, M., DeFelice, L.J. 1988. K channel kinetics during the spontaneous beat in embryonic chick heart.Biophys. J. 54:1139–1148
Mazzanti, M., DeFelice, L.J. 1989. Mode II conduction in single Ca channels in 10mm Ca.Biophys. J. 55:595a
Mazzanti, M., DiFrancesco, D. 1989. Intracellular Ca modulates K-inward rectification in cardiac myocytes.Pfluegers Arch.413:322–324
Sakmann, B., Trube, G. 1984a. Conductance properties of single inwardly rectifying K channels in ventricular guinea-pig.J. Physiol. (London) 347:641–657
Sakmann, B., Trube, G. 1984b. Voltage-dependent inactivation of inwardly-rectifying single-channel currents in the guineapig.J. Physiol. (London) 347:659–683
Satin, J., DeHaan, R.L. 1989. The time-dependence of the inward rectifier in embryonic chick ventricle cells changes with development.Biophys. J. 55:547a
Vandenberg, C.A. 1987. Inward rectification of K channels in cardiac ventricular cells depends on internal Mg ions.Proc. Natl. Acad. Sci. USA 84:2560–2564
Wellis, D.P., DeFelice, L.J., Mazzanti, M. 1990. Outward Na current in beating heart cells.Biophys. J. (in press)
White, R.E., Hartzell, H.C. 1988. Effects of intracellular free Mg on Ca current in isolated cardiac myocytes.Science 239:778–780
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mazzanti, M., DeFelice, L.J. Ca modulates outward current throughI K1 channels. J. Membrain Biol. 116, 41–45 (1990). https://doi.org/10.1007/BF01871670
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01871670