The calcium and voltage clocks in sinoatrial node automaticity

Boyoung Joung, Masahiro Ogawa, Shien-Fong Lin, Peng-Sheng Chen

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Recent evidence indicates that the voltage (cyclic activation and deactivation of membrane ion channels) and Ca2+ clocks (rhythmic spontaneous sarcoplasmic reticulum Ca2+ release) jointly regulate sinoatrial node (SAN) automaticity. Since the intact SAN is a heterogeneous structure that includes multiple different cell types interacting with each other, the relative importance of the voltage and Ca2+ clocks for pacemaking may be variable in different regions of the SAN. Recently, we performed optical mapping in isolated and Langendorff-perfused canine right atria. We mapped the intracellular calcium (Cai) and membrane potentials of the intact SAN simultaneously. Using previously described criteria of the timing of the late diastolic Cai elevation (LDCAE) relative to the action potential upstroke to detect Ca2+ clock activity, we demonstrated that the sinus rate increased and the leading pacemaker shifted to the superior SAN with the robust LDCAE during β-adrenergic stimulation. We also showed that the LDCAE was caused by spontaneous diastolic SR Ca 2+ release and was closely related with heart rate changes. We conclude that the Ca and voltage clocks work synergistically to generate SAN automaticity.

Original languageEnglish
Pages (from-to)217-222
Number of pages6
JournalKorean Circulation Journal
Volume39
Issue number6
DOIs
StatePublished - Jun 2009

Fingerprint

Sinoatrial Node
Calcium
Ion Channels
Intracellular Membranes
Sarcoplasmic Reticulum
Heart Atria
Adrenergic Agents
Membrane Potentials
Action Potentials
Canidae
Heart Rate

Keywords

  • Calcium
  • Sarcoplasmic reticulum
  • Sinoatrial node
  • Sympathetic nervous system

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Internal Medicine

Cite this

The calcium and voltage clocks in sinoatrial node automaticity. / Joung, Boyoung; Ogawa, Masahiro; Lin, Shien-Fong; Chen, Peng-Sheng.

In: Korean Circulation Journal, Vol. 39, No. 6, 06.2009, p. 217-222.

Research output: Contribution to journalArticle

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