Abstract
With no Ca in the patch electrode, two kinds of channels conduct Na in spontaneously beating embryonic chick heart cells. One channel conducts Na primarily during the upstroke of the action potential and is blocked by tetrodotoxin (TTX). The other channel conducts Na primarily during the late plateau and early repolarization phase of the action potential, but only in Ca concentrations below 10(-6) M. This second channel is TTX-insensitive and has a conductance of 50 to 90 pS, depending upon the interpretation of open-channel flickering. These two Na-conducting channels correspond to the channels that normally carry the fast Na current (INa) and the slow Ca current (Isi).
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- 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]
- Cavalié A., Ochi R., Pelzer D., Trautwein W. Elementary currents through Ca2+ channels in guinea pig myocytes. Pflugers Arch. 1983 Sep;398(4):284–297. doi: 10.1007/BF00657238. [DOI] [PubMed] [Google Scholar]
- DeHann R. L. Regulation of spontaneous activity and growth of embryonic chick heart cells in tissue culture. Dev Biol. 1967 Sep;16(3):216–249. doi: 10.1016/0012-1606(67)90025-5. [DOI] [PubMed] [Google Scholar]
- Fischmeister R., DeFelice L. J., Ayer R. K., Jr, Levi R., DeHaan R. L. Channel currents during spontaneous action potentials in embryonic chick heart cells. The action potential patch clamp. Biophys J. 1984 Aug;46(2):267–271. doi: 10.1016/S0006-3495(84)84020-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Garnier D., Rougier O., Gargouïl Y. M., Coraboeuf E. Analyse électrophysiologique du plateau des réponses myocardiques, mise en évidence d'un courant lent entrant en absence d'ions bivalents. Pflugers Arch. 1969;313(4):321–342. doi: 10.1007/BF00593957. [DOI] [PubMed] [Google Scholar]
- 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]
- 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]
- Kostyuk P. G., Krishtal O. A. Effects of calcium and calcium-chelating agents on the inward and outward current in the membrane of mollusc neurones. J Physiol. 1977 Sep;270(3):569–580. doi: 10.1113/jphysiol.1977.sp011969. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kostyuk P. G., Krishtal O. A., Shakhovalov Y. A. Separation of sodium and calcium currents in the somatic membrane of mollusc neurones. J Physiol. 1977 Sep;270(3):545–568. doi: 10.1113/jphysiol.1977.sp011968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- 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]
- 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]