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. 1987 Jul;52(1):95–100. doi: 10.1016/S0006-3495(87)83192-2

Na channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells.

M Mazzanti, L J DeFelice
PMCID: PMC1329987  PMID: 2440494

Abstract

Using cell-attached and whole-cell recording techniques simultaneously allows the measurement of Na currents during action potentials in beating heart cells. In 7-d chick ventricle, the dynamic reversal potential for Na is 30 mV, which is 20 mV less than the reversal potential in nonbeating cells. This result implies that the spontaneous activity of heart cells raises the Na concentration at the internal face of the membrane to nearly 40 mM. Fitting the Na action currents to the Hodgkin and Huxley equations shows that patches may contain from 50 to 700 Na channels, with an average density of 23 +/- 21 per micron2. Only approximately 2% of the available Na channels are open at the peak of the Na action current. This low probability is a consequence of the channels' continual inactivation during the diastolic depolarization phase.

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Selected References

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

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