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Simulation of Ca2+-activated Cl- current of cardiomyocytes in rabbit pulmonary vein: implications of subsarcolemmal Ca2+ dynamics

Cited 9 time in Web of Science Cited 9 time in Scopus
Authors
Leem, Chae Hun; Kim, Won Tae; Ha, Jeong Mi; Lee, Yoon Jin; Seong, Hyeon Chan; Choe, Han; Jang, Yeon Jin; Youm, Jae Boum; Earm, Yung E
Issue Date
2006-04-13
Publisher
Royal Society, The
Citation
Philos Transact A Math Phys Eng Sci. 364(1842), 1223-1243
Keywords
Action Potentials/*physiologyAnimalsCalcium/*metabolismCalcium Signaling/physiologyCells, CulturedChlorine/*metabolismComputer SimulationMembrane Potentials/physiology*Models, CardiovascularMyocytes, Cardiac/*physiologyPulmonary Veins/cytology/*physiologyRabbitsSarcolemma/*physiology
Abstract
In recent studies, we recorded transiently activated outward currents by the application of three-step voltage pulses to induce a reverse mode of Na+-Ca2+ exchange (NCX). We found that these currents were mediated by a Ca2+-activated Cl- current. Based on the recent reports describing the atrial Ca2+ transients, the Ca2+ transient at the subsarcolemmal space was initiated and then diffused into the cytosolic space. Because the myocardium in the pulmonary vein is an extension of the atrium, the Ca2+-activated Cl- current may reflect the subsarcolemmal Ca2+ dynamics. We tried to predict the subsarcolemmal Ca2+ dynamics by simulating these current traces. According to recent reports on the geometry of atrial myocytes, we assumed that there were three compartments of sarcoplasmic reticulum (SR): a network SR, a junctional SR and a central SR. Based on these structures, we also divided the cytosolic space into three compartments: the junctional, subsarcolemmal and cytosolic spaces. Geometry information and cellular capacitance suggested that there were essentially no T-tubules in these cells. The basic physical data, such as the compartmental volumes, the diffusion coefficients and the stability coefficients of the Ca2+ buffers, were obtained from the literature. In the simulation, we incorporated the NCX, the L-type Ca2+ channel, the rapid activating outward rectifier K+ channel, the Na+-K+ pump, the SR Ca2+-pump, the ryanodine receptor, the Ca2+-activated Cl- channel and the dynamics of Na+, K+, Ca2+ and Cl-. In these conditions, we could successfully reconstruct the Ca2+-activated Cl- currents. The simulation allowed estimation of the Ca2+ dynamics of each compartment and the distribution of the Ca2+-activated Cl- channel and the NCX in the sarcolemma on the junctional or subsarcolemmal space.
ISSN
1364-503X (Print)
Language
English
URI
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16608705

http://hdl.handle.net/10371/68471
DOI
https://doi.org/10.1098/rsta.2006.1766
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Physiology (생리학교실)Journal Papers (저널논문_생리학교실)
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