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Rhythmic Ryanodine Receptor Ca 2+

Rhythmic Ryanodine Receptor Ca 2+ Rhythmic Ryanodine Receptor Ca Releases During Diastolic Depolarization of Sinoatrial Pacemaker Cells Do Not Require Membrane Depolarization Tatiana M. Vinogradova, Ying-Ying Zhou, Victor Maltsev, Alexey Lyashkov, Michael Stern, Edward G. Lakatta Abstract—Localized, subsarcolemmal Ca release (LCR) via ryanodine receptors (RyRs) during diastolic depolarization of sinoatrial nodal cells augments the terminal depolarization rate. We determined whether LCRs in rabbit sinoatrial nodal cells require the concurrent membrane depolarization, or are intrinsically rhythmic, and whether rhythmicity is linked to the spontaneous cycle length. Confocal linescan images revealed persistent LCRs both in saponin-permeab- ilized cells and in spontaneously beating cells acutely voltage-clamped at the maximum diastolic potential. During the initial stage of voltage clamp, the LCR spatiotemporal characteristics did not differ from those in spontaneously beating cells, or in permeabilized cells bathed in 150 nmol/L Ca . The period of persistent rhythmic LCRs during voltage clamp was slightly less than the spontaneous cycle length before voltage clamp. In spontaneously beating cells, in both transient and steady states, LCR period was highly correlated with the spontaneous cycle length; and regardless of the cycle length, LCRs occurred predominantly at a constant time, ie, 80% to 90% of the cycle length. Numerical model simulations incorporating LCRs http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Circulation Research Wolters Kluwer Health

Rhythmic Ryanodine Receptor Ca 2+

Lakatta, Edward G.
Circulation Research , Volume 94 (6) – Apr 1, 2004
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References (40)

ISSN
0009-7330
eISSN
1524-4571
DOI
10.1161/01.RES.0000122045.55331.0F
pmid
14963011
Publisher site
See Article on Publisher Site

Abstract

Rhythmic Ryanodine Receptor Ca Releases During Diastolic Depolarization of Sinoatrial Pacemaker Cells Do Not Require Membrane Depolarization Tatiana M. Vinogradova, Ying-Ying Zhou, Victor Maltsev, Alexey Lyashkov, Michael Stern, Edward G. Lakatta Abstract—Localized, subsarcolemmal Ca release (LCR) via ryanodine receptors (RyRs) during diastolic depolarization of sinoatrial nodal cells augments the terminal depolarization rate. We determined whether LCRs in rabbit sinoatrial nodal cells require the concurrent membrane depolarization, or are intrinsically rhythmic, and whether rhythmicity is linked to the spontaneous cycle length. Confocal linescan images revealed persistent LCRs both in saponin-permeab- ilized cells and in spontaneously beating cells acutely voltage-clamped at the maximum diastolic potential. During the initial stage of voltage clamp, the LCR spatiotemporal characteristics did not differ from those in spontaneously beating cells, or in permeabilized cells bathed in 150 nmol/L Ca . The period of persistent rhythmic LCRs during voltage clamp was slightly less than the spontaneous cycle length before voltage clamp. In spontaneously beating cells, in both transient and steady states, LCR period was highly correlated with the spontaneous cycle length; and regardless of the cycle length, LCRs occurred predominantly at a constant time, ie, 80% to 90% of the cycle length. Numerical model simulations incorporating LCRs

Journal

Circulation Research – Wolters Kluwer Health

Published: Apr 1, 2004

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