NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide

Aims: The small conductance calcium activated potassium channel (KCNN1-3; KCa2.1–3) is recognized as a possible new anti-arrhythmic drug target for treatment of atrial fibrillation (AF). The aim of this study is to investigate potential ventricular effects of KCa2 channel inhibition under normal, br...

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Main Authors: Yannan Yan, Lea Abildgaard, Mark Alexander Skarsfeldt, Sofia Hammami Bomholtz, Ulrik Sørensen, Anders Gaarsdal Holst, Morten Grunnet, Jonas Goldin Diness, Bo Hjorth Bentzen
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:International Journal of Cardiology: Heart & Vasculature
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Online Access:http://www.sciencedirect.com/science/article/pii/S2352906725001022
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author Yannan Yan
Lea Abildgaard
Mark Alexander Skarsfeldt
Sofia Hammami Bomholtz
Ulrik Sørensen
Anders Gaarsdal Holst
Morten Grunnet
Jonas Goldin Diness
Bo Hjorth Bentzen
author_facet Yannan Yan
Lea Abildgaard
Mark Alexander Skarsfeldt
Sofia Hammami Bomholtz
Ulrik Sørensen
Anders Gaarsdal Holst
Morten Grunnet
Jonas Goldin Diness
Bo Hjorth Bentzen
author_sort Yannan Yan
collection DOAJ
description Aims: The small conductance calcium activated potassium channel (KCNN1-3; KCa2.1–3) is recognized as a possible new anti-arrhythmic drug target for treatment of atrial fibrillation (AF). The aim of this study is to investigate potential ventricular effects of KCa2 channel inhibition under normal, bradycardic and hypokalemic conditions and compare these to classical class I and III anti-arrhythmic drugs. Methods and results: Rabbit hearts were isolated, AV-ablated, mounted in an ex vivo Langendorff preparation and perfused with normokalemic (4 mM K+) Krebs-Henseleit solution, followed by perfusion with drug (AP14145 3 µM; AP30663 1.5 µM; dofetilide 10 nM; flecainide 1.5 µM) or vehicle control. The perfusion was then changed to hypokalemic solution (2.5 mM K+) in presence of drug. Changes in ventricular action potential duration were assessed by monophasic action potential recordings. Neither of the KCa2 channel inhibitors (AP14145 or AP30663) or flecainide (NaV1.5 inhibitor) prolonged ventricular action potential duration (APD90) or increased pro-arrhythmic markers, whereas dofetilide (KV11.1 blocker) prolonged APD and increased the susceptibility to ventricular arrhythmia. Conclusions: These findings suggests that KCa2 channels have minimal importance for ventricular repolarization in healthy rabbit hearts under both normo- and hypokalemic conditions.
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issn 2352-9067
language English
publishDate 2025-08-01
publisher Elsevier
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series International Journal of Cardiology: Heart & Vasculature
spelling doaj-art-650c91dc3b004a708cbf01e6d11bfa812025-08-20T02:56:29ZengElsevierInternational Journal of Cardiology: Heart & Vasculature2352-90672025-08-015910169910.1016/j.ijcha.2025.101699NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilideYannan Yan0Lea Abildgaard1Mark Alexander Skarsfeldt2Sofia Hammami Bomholtz3Ulrik Sørensen4Anders Gaarsdal Holst5Morten Grunnet6Jonas Goldin Diness7Bo Hjorth Bentzen8Department of Biomedical Sciences, University of Copenhagen, DenmarkAcesion Pharma, DenmarkDepartment of Biomedical Sciences, University of Copenhagen, Denmark; Acesion Pharma, DenmarkDepartment of Biomedical Sciences, University of Copenhagen, Denmark; Acesion Pharma, DenmarkAcesion Pharma, DenmarkAcesion Pharma, DenmarkAcesion Pharma, DenmarkAcesion Pharma, DenmarkDepartment of Biomedical Sciences, University of Copenhagen, Denmark; Acesion Pharma, Denmark; Corresponding author at: Department of Biomedical Sciences, University of Copenhagen Blegdamsvej 3B, DK‐2200 Copenhagen, Denmark.Aims: The small conductance calcium activated potassium channel (KCNN1-3; KCa2.1–3) is recognized as a possible new anti-arrhythmic drug target for treatment of atrial fibrillation (AF). The aim of this study is to investigate potential ventricular effects of KCa2 channel inhibition under normal, bradycardic and hypokalemic conditions and compare these to classical class I and III anti-arrhythmic drugs. Methods and results: Rabbit hearts were isolated, AV-ablated, mounted in an ex vivo Langendorff preparation and perfused with normokalemic (4 mM K+) Krebs-Henseleit solution, followed by perfusion with drug (AP14145 3 µM; AP30663 1.5 µM; dofetilide 10 nM; flecainide 1.5 µM) or vehicle control. The perfusion was then changed to hypokalemic solution (2.5 mM K+) in presence of drug. Changes in ventricular action potential duration were assessed by monophasic action potential recordings. Neither of the KCa2 channel inhibitors (AP14145 or AP30663) or flecainide (NaV1.5 inhibitor) prolonged ventricular action potential duration (APD90) or increased pro-arrhythmic markers, whereas dofetilide (KV11.1 blocker) prolonged APD and increased the susceptibility to ventricular arrhythmia. Conclusions: These findings suggests that KCa2 channels have minimal importance for ventricular repolarization in healthy rabbit hearts under both normo- and hypokalemic conditions.http://www.sciencedirect.com/science/article/pii/S2352906725001022KCa2 channelsSK channelsHypokalemiaQT-intervalPharmacologyArrhythmia
spellingShingle Yannan Yan
Lea Abildgaard
Mark Alexander Skarsfeldt
Sofia Hammami Bomholtz
Ulrik Sørensen
Anders Gaarsdal Holst
Morten Grunnet
Jonas Goldin Diness
Bo Hjorth Bentzen
NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
International Journal of Cardiology: Heart & Vasculature
KCa2 channels
SK channels
Hypokalemia
QT-interval
Pharmacology
Arrhythmia
title NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
title_full NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
title_fullStr NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
title_full_unstemmed NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
title_short NaV1.5 or KCa2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts, unlike KV11.1 inhibition with dofetilide
title_sort nav1 5 or kca2 channel blockade does not increase arrhythmia risk in hypokalemic rabbit hearts unlike kv11 1 inhibition with dofetilide
topic KCa2 channels
SK channels
Hypokalemia
QT-interval
Pharmacology
Arrhythmia
url http://www.sciencedirect.com/science/article/pii/S2352906725001022
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