Synergistic dual automaticity in sinoatrial node cell and tissue models

Hong Zhang, Boyoung Joung, Tetsuji Shinohara, Xi Mei, Peng Sheng Chen, Shien Fong Lin

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Background: The mechanism of sinoatrial node (SAN) automaticity is traditionally attributed to membrane ion currents. Recent evidence indicates spontaneous sarcoplasmic reticulum (SR) Ca2+ cycling also plays an important role. Methods and Results: A computer simulation on SAN cell and 1D tissue model was performed. In the SAN cells, SR Ca2+ cycling broadly modulated the sinus rate from 1.74 Hz to 3.87 Hz. Shortening of the junctional SR refilling time and increase of SR Ca2+ release were responsible for sinus rate acceleration. However, under the fast SR Ca2+ cycling, decreased L-type Ca2+ current (ICaL) resulted in irregular firing. When Ca2+ cycling was suppressed, If and ICaT both acted to stabilize the pacemaker rhythm, but ICaT had less effect than If. At the 1D level, the electrical coupling between neighboring cells had little effect on the earliest pacemaker location. The leading pacemaking site always colocalized with the site with the highest SR Ca2+ cycling rate, but shifted to the site with less inhibited ICaL. Conclusions: The rate of SR Ca2+ cycling can effectively and broadly modulate the sinus rate. If, ICaL and ICaT play integral roles to guarantee SAN cell rhythmic firing. The leading pacemaker site is determined by intracellular Ca2+ dynamics and membrane currents, indicating the synergistic dual automaticity not only exists in single SAN cells, but also at the tissue level.

Original languageEnglish
Pages (from-to)2079-2088
Number of pages10
JournalCirculation Journal
Volume74
Issue number10
DOIs
Publication statusPublished - 2010 Oct 25

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Sinoatrial Node
Sarcoplasmic Reticulum
Membranes
Computer Simulation
Ions

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

Cite this

Zhang, Hong ; Joung, Boyoung ; Shinohara, Tetsuji ; Mei, Xi ; Chen, Peng Sheng ; Lin, Shien Fong. / Synergistic dual automaticity in sinoatrial node cell and tissue models. In: Circulation Journal. 2010 ; Vol. 74, No. 10. pp. 2079-2088.
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abstract = "Background: The mechanism of sinoatrial node (SAN) automaticity is traditionally attributed to membrane ion currents. Recent evidence indicates spontaneous sarcoplasmic reticulum (SR) Ca2+ cycling also plays an important role. Methods and Results: A computer simulation on SAN cell and 1D tissue model was performed. In the SAN cells, SR Ca2+ cycling broadly modulated the sinus rate from 1.74 Hz to 3.87 Hz. Shortening of the junctional SR refilling time and increase of SR Ca2+ release were responsible for sinus rate acceleration. However, under the fast SR Ca2+ cycling, decreased L-type Ca2+ current (ICaL) resulted in irregular firing. When Ca2+ cycling was suppressed, If and ICaT both acted to stabilize the pacemaker rhythm, but ICaT had less effect than If. At the 1D level, the electrical coupling between neighboring cells had little effect on the earliest pacemaker location. The leading pacemaking site always colocalized with the site with the highest SR Ca2+ cycling rate, but shifted to the site with less inhibited ICaL. Conclusions: The rate of SR Ca2+ cycling can effectively and broadly modulate the sinus rate. If, ICaL and ICaT play integral roles to guarantee SAN cell rhythmic firing. The leading pacemaker site is determined by intracellular Ca2+ dynamics and membrane currents, indicating the synergistic dual automaticity not only exists in single SAN cells, but also at the tissue level.",
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Zhang, H, Joung, B, Shinohara, T, Mei, X, Chen, PS & Lin, SF 2010, 'Synergistic dual automaticity in sinoatrial node cell and tissue models', Circulation Journal, vol. 74, no. 10, pp. 2079-2088. https://doi.org/10.1253/circj.CJ-10-0265

Synergistic dual automaticity in sinoatrial node cell and tissue models. / Zhang, Hong; Joung, Boyoung; Shinohara, Tetsuji; Mei, Xi; Chen, Peng Sheng; Lin, Shien Fong.

In: Circulation Journal, Vol. 74, No. 10, 25.10.2010, p. 2079-2088.

Research output: Contribution to journalArticle

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T1 - Synergistic dual automaticity in sinoatrial node cell and tissue models

AU - Zhang, Hong

AU - Joung, Boyoung

AU - Shinohara, Tetsuji

AU - Mei, Xi

AU - Chen, Peng Sheng

AU - Lin, Shien Fong

PY - 2010/10/25

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N2 - Background: The mechanism of sinoatrial node (SAN) automaticity is traditionally attributed to membrane ion currents. Recent evidence indicates spontaneous sarcoplasmic reticulum (SR) Ca2+ cycling also plays an important role. Methods and Results: A computer simulation on SAN cell and 1D tissue model was performed. In the SAN cells, SR Ca2+ cycling broadly modulated the sinus rate from 1.74 Hz to 3.87 Hz. Shortening of the junctional SR refilling time and increase of SR Ca2+ release were responsible for sinus rate acceleration. However, under the fast SR Ca2+ cycling, decreased L-type Ca2+ current (ICaL) resulted in irregular firing. When Ca2+ cycling was suppressed, If and ICaT both acted to stabilize the pacemaker rhythm, but ICaT had less effect than If. At the 1D level, the electrical coupling between neighboring cells had little effect on the earliest pacemaker location. The leading pacemaking site always colocalized with the site with the highest SR Ca2+ cycling rate, but shifted to the site with less inhibited ICaL. Conclusions: The rate of SR Ca2+ cycling can effectively and broadly modulate the sinus rate. If, ICaL and ICaT play integral roles to guarantee SAN cell rhythmic firing. The leading pacemaker site is determined by intracellular Ca2+ dynamics and membrane currents, indicating the synergistic dual automaticity not only exists in single SAN cells, but also at the tissue level.

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