Diastolic Calcium Release Controls the Beating Rate of Rabbit Sinoatrial Node Cells: Numerical Modeling of the Coupling Process

Victor A. Maltsev, Tatiana M. Vinogradova, Konstantin Y. Bogdanov, Edward Lakatta, Michael D. Stern

Research output: Contribution to journalArticle

Abstract

Recent studies employing Ca2+ indicators and confocal microscopy demonstrate substantial local Ca2+ release beneath the cell plasma membrane (subspace) of sinoatrial node cells (SANCs) occurring during diastolic depolarization. Pharmacological and biophysical experiments have suggested that the released Ca2+ interacts with the plasma membrane via the ion current (/NaCa) produced by the Na +/Ca2+ exchanger and constitutes an important determinant of the pacemaker rate. This study provides a numerical validation of the functional importance of diastolic Ca2+ release for rate control. The subspace Ca2+ signals in rabbit SANCs were measured by laser confocal microscopy, averaged, and calibrated. The time course of the subspace [Ca2+] displayed both diastolic and systolic components. The diastolic component was mainly due to the local Ca2+ releases; it was numerically approximated and incorporated into a SANC cellular electrophysiology model. The model predicts that the diastolic Ca2+ release strongly interacts with plasma membrane via /NaCa and thus controls the phase of the action potential upstroke and ultimately the final action potential rate.

Original languageEnglish (US)
Pages (from-to)2596-2605
Number of pages10
JournalBiophysical Journal
Volume86
Issue number4
StatePublished - Apr 2004
Externally publishedYes

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Sinoatrial Node
Cell Membrane
Confocal Microscopy
Rabbits
Calcium
Action Potentials
Electrophysiology
Pharmacology
Ions

ASJC Scopus subject areas

  • Biophysics

Cite this

Diastolic Calcium Release Controls the Beating Rate of Rabbit Sinoatrial Node Cells : Numerical Modeling of the Coupling Process. / Maltsev, Victor A.; Vinogradova, Tatiana M.; Bogdanov, Konstantin Y.; Lakatta, Edward; Stern, Michael D.

In: Biophysical Journal, Vol. 86, No. 4, 04.2004, p. 2596-2605.

Research output: Contribution to journalArticle

Maltsev, Victor A. ; Vinogradova, Tatiana M. ; Bogdanov, Konstantin Y. ; Lakatta, Edward ; Stern, Michael D. / Diastolic Calcium Release Controls the Beating Rate of Rabbit Sinoatrial Node Cells : Numerical Modeling of the Coupling Process. In: Biophysical Journal. 2004 ; Vol. 86, No. 4. pp. 2596-2605.
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