Document Detail


Local control of Ca2+-induced Ca2+ release in mouse sinoatrial node cells.
MedLine Citation:
PMID:  19615376     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Emerging evidence from large animal models implicates Ca2+ regulation, particularly intracellular sarcoplasmic reticulum (SR) Ca2+ release, as essential for sinoatrial node (SAN) automaticity. However, despite the apparent importance of SR Ca2+ release to SAN cell function it is uncertain how SR Ca2+ release is controlled in SAN cells from mouse. Understanding mouse SAN SR Ca2+ release mechanism will allow improved understanding of results in studies on SAN from genetic mouse models of Ca2+ homeostatic proteins. Here we investigated the functional relationship between sarcolemmal Ca2+ influx and SR Ca2+ release at the level of single SAN cell, using simultaneous patch-clamp current recording and high resolution confocal Ca2+ imaging techniques. In mouse SAN cells, both Ca2+ channel currents and triggered SR Ca2+ transients displayed bell-shaped, graded function with the membrane potential. Moreover, the gain function for Ca2+-induced Ca2+ release (CICR) displayed a monotonically decreasing function with strong voltage dependence, consistent with a "local control" mechanism for CICR. In addition, we observed numerous discrete Ca2+ sparks at the voltage range of diastolic depolarization, in sharp contrast to the much lower frequency of sparks observed at resting potentials. We concluded that the "local control" mechanism of CICR is responsible for both local Ca2+ release during diastolic depolarization and the synchronized Ca2+ transients observed during action potential in SAN cells.
Authors:
Biyi Chen; Yuejin Wu; Peter J Mohler; Mark E Anderson; Long-Sheng Song
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2009-07-15
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  47     ISSN:  1095-8584     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  2009 Nov 
Date Detail:
Created Date:  2009-10-13     Completed Date:  2009-12-24     Revised Date:  2011-10-11    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  706-15     Citation Subset:  IM    
Affiliation:
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, 285 Newton Road, Iowa City, IA 52242, USA.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology
Animals
Calcium / metabolism*
Cells, Cultured
Electrophysiology
Mice
Patch-Clamp Techniques
Sarcoplasmic Reticulum / metabolism*
Sinoatrial Node / metabolism*
Grant Support
ID/Acronym/Agency:
HL079031/HL/NHLBI NIH HHS; HL083422/HL/NHLBI NIH HHS; HL084583/HL/NHLBI NIH HHS; HL62494/HL/NHLBI NIH HHS; HL70250/HL/NHLBI NIH HHS; R01 HL090905/HL/NHLBI NIH HHS; R01 HL090905-01/HL/NHLBI NIH HHS; R01 HL090905-02/HL/NHLBI NIH HHS; R01 HL090905-05/HL/NHLBI NIH HHS; R01 HL096652-03/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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