Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp

Introduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Consequently, novel therapies are being developed. Ultimately, the impact of compounds on the action potential (AP) needs to be tested in freshly isolated human atrial myocytes. However, the frequent depolarized state of t...

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Main Authors: Arie O. Verkerk, Gerard A. Marchal, Jan G. Zegers, Makiri Kawasaki, Antoine H. G. Driessen, Carol Ann Remme, Joris R. de Groot, Ronald Wilders
Format: Article
Language:English
Published: Frontiers Media S.A. 2021-04-01
Series:Frontiers in Pharmacology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fphar.2021.649414/full
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author Arie O. Verkerk
Arie O. Verkerk
Gerard A. Marchal
Jan G. Zegers
Makiri Kawasaki
Antoine H. G. Driessen
Carol Ann Remme
Joris R. de Groot
Ronald Wilders
author_facet Arie O. Verkerk
Arie O. Verkerk
Gerard A. Marchal
Jan G. Zegers
Makiri Kawasaki
Antoine H. G. Driessen
Carol Ann Remme
Joris R. de Groot
Ronald Wilders
author_sort Arie O. Verkerk
collection DOAJ
description Introduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Consequently, novel therapies are being developed. Ultimately, the impact of compounds on the action potential (AP) needs to be tested in freshly isolated human atrial myocytes. However, the frequent depolarized state of these cells upon isolation seriously hampers reliable AP recordings.Purpose: We assessed whether AP recordings from single human atrial myocytes could be improved by providing these cells with a proper inward rectifier K+ current (IK1), and consequently with a regular, non-depolarized resting membrane potential (RMP), through “dynamic clamp”.Methods: Single myocytes were enzymatically isolated from left atrial appendage tissue obtained from patients with paroxysmal AF undergoing minimally invasive surgical ablation. APs were elicited at 1 Hz and measured using perforated patch-clamp methodology, injecting a synthetic IK1 to generate a regular RMP. The injected IK1 had strong or moderate rectification. For comparison, a regular RMP was forced through injection of a constant outward current. A wide variety of ion channel blockers was tested to assess their modulatory effects on AP characteristics.Results: Without any current injection, RMPs ranged from −9.6 to −86.2 mV in 58 cells. In depolarized cells (RMP positive to −60 mV), RMP could be set at −80 mV using IK1 or constant current injection and APs could be evoked upon stimulation. AP duration differed significantly between current injection methods (p < 0.05) and was shortest with constant current injection and longest with injection of IK1 with strong rectification. With moderate rectification, AP duration at 90% repolarization (APD90) was similar to myocytes with regular non-depolarized RMP, suggesting that a synthetic IK1 with moderate rectification is the most appropriate for human atrial myocytes. Importantly, APs evoked using each injection method were still sensitive to all drugs tested (lidocaine, nifedipine, E-4031, low dose 4-aminopyridine, barium, and apamin), suggesting that the major ionic currents of the atrial cells remained functional. However, certain drug effects were quantitatively dependent on the current injection approach used.Conclusion: Injection of a synthetic IK1 with moderate rectification facilitates detailed AP measurements in human atrial myocytes. Therefore, dynamic clamp represents a promising tool for testing novel antiarrhythmic drugs.
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spelling doaj.art-bcf3988a253842a6aaf10994a35a74452022-12-21T23:47:05ZengFrontiers Media S.A.Frontiers in Pharmacology1663-98122021-04-011210.3389/fphar.2021.649414649414Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic ClampArie O. Verkerk0Arie O. Verkerk1Gerard A. Marchal2Jan G. Zegers3Makiri Kawasaki4Antoine H. G. Driessen5Carol Ann Remme6Joris R. de Groot7Ronald Wilders8Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Cardiothoracic Surgery, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsDepartment of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, NetherlandsIntroduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Consequently, novel therapies are being developed. Ultimately, the impact of compounds on the action potential (AP) needs to be tested in freshly isolated human atrial myocytes. However, the frequent depolarized state of these cells upon isolation seriously hampers reliable AP recordings.Purpose: We assessed whether AP recordings from single human atrial myocytes could be improved by providing these cells with a proper inward rectifier K+ current (IK1), and consequently with a regular, non-depolarized resting membrane potential (RMP), through “dynamic clamp”.Methods: Single myocytes were enzymatically isolated from left atrial appendage tissue obtained from patients with paroxysmal AF undergoing minimally invasive surgical ablation. APs were elicited at 1 Hz and measured using perforated patch-clamp methodology, injecting a synthetic IK1 to generate a regular RMP. The injected IK1 had strong or moderate rectification. For comparison, a regular RMP was forced through injection of a constant outward current. A wide variety of ion channel blockers was tested to assess their modulatory effects on AP characteristics.Results: Without any current injection, RMPs ranged from −9.6 to −86.2 mV in 58 cells. In depolarized cells (RMP positive to −60 mV), RMP could be set at −80 mV using IK1 or constant current injection and APs could be evoked upon stimulation. AP duration differed significantly between current injection methods (p < 0.05) and was shortest with constant current injection and longest with injection of IK1 with strong rectification. With moderate rectification, AP duration at 90% repolarization (APD90) was similar to myocytes with regular non-depolarized RMP, suggesting that a synthetic IK1 with moderate rectification is the most appropriate for human atrial myocytes. Importantly, APs evoked using each injection method were still sensitive to all drugs tested (lidocaine, nifedipine, E-4031, low dose 4-aminopyridine, barium, and apamin), suggesting that the major ionic currents of the atrial cells remained functional. However, certain drug effects were quantitatively dependent on the current injection approach used.Conclusion: Injection of a synthetic IK1 with moderate rectification facilitates detailed AP measurements in human atrial myocytes. Therefore, dynamic clamp represents a promising tool for testing novel antiarrhythmic drugs.https://www.frontiersin.org/articles/10.3389/fphar.2021.649414/fulldrug testingpatch clamphumancardiac myocytesleft atrial appendageaction potential
spellingShingle Arie O. Verkerk
Arie O. Verkerk
Gerard A. Marchal
Jan G. Zegers
Makiri Kawasaki
Antoine H. G. Driessen
Carol Ann Remme
Joris R. de Groot
Ronald Wilders
Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
Frontiers in Pharmacology
drug testing
patch clamp
human
cardiac myocytes
left atrial appendage
action potential
title Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
title_full Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
title_fullStr Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
title_full_unstemmed Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
title_short Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp
title_sort patch clamp recordings of action potentials from human atrial myocytes optimization through dynamic clamp
topic drug testing
patch clamp
human
cardiac myocytes
left atrial appendage
action potential
url https://www.frontiersin.org/articles/10.3389/fphar.2021.649414/full
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