Evidence map›Paper›PMID 23089919›Full record

ArticleEuropean biophysics journal : EBJ2013

Depolarization-induced automaticity in rat ventricular cardiomyocytes is based on the gating properties of L-type calcium and slow Kv channels.

Dirk L Ypey, Wilbert P M van Meerwijk, Soban Umar, Daniel A Pijnappels, Martin J Schalij, Arnoud van der Laarse

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Article in European biophysics journal : EBJ, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

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1citing papers in PubMed
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1 · What the graph read from it

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3 · Its place in the literature

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1 citing paper in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Dirk L YpeyDepartment of Cardiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
Wilbert P M van Meerwijk
Soban Umar
Daniel A Pijnappels
Martin J Schalij
Arnoud van der Laarse

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Depolarization-induced automaticity (DIA) of cardiomyocytes is the property of those cells to generate pacemaker cell-like spontaneous electrical activity when subjected to a depolarizing current. This property provides a candidate mechanism for generation of pathogenic ectopy in cardiac tissue. The purpose of this study was to determine the biophysical mechanism of DIA in terms of the ion conductance properties of the cardiomyocyte membrane. First, we determined, by use of the conventional whole-cell patch-clamp technique, the membrane conductance and DIA properties of ventricular cardiomyocytes isolated from adult rat heart. Second, we reproduced and analysed DIA properties by using an adapted version of the experimentally based mathematical cardiomyocyte model of Pandit et al. (Biophys J 81:3029-3051 2001, Biophys J 84:832-841 2003) and Padmala and Demir (J Cardiovasc Electrophysiol 14:990-995 2003). DIA in 23 rat cardiomyocytes was a damped membrane potential oscillation with a variable number of action potentials and/or waves, depending on the strength of the depolarizing current and the particular cell. The adapted model was used to reconstruct the DIA properties of a particular cardiomyocyte from its whole-cell voltage-clamp currents. The main currents involved in DIA were an L-type calcium current (I CaL) and a slowly activating and inactivating Kv current (I ss), with linear (I B) and inward rectifier (I K1) currents acting as background currents and I Na and I t as modulators. Essential for DIA is a sufficiently large window current of a slowly inactivating I CaL combined with a critically sized repolarizing current I ss. Slow inactivation of I ss makes DIA transient. In conclusion, we established a membrane mechanism of DIA primarily based on I CaL, I ss and inward rectifier properties; this may be helpful in understanding cardiac ectopy and its treatment.

Indexed as

Ion Channel GatingMembrane PotentialsAction PotentialsAnimalsCalcium Channels, L-TypeElectric ConductivityFemaleHeart VentriclesModels, BiologicalMyocytes, CardiacPotassium Channels, Voltage-GatedRatsRats, WistarCalcium Channels, L-TypePotassium Channels, Voltage-Gated

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.