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Magyar T, Árpádffy-Lovas T, Pászti B, Tóth N, Szlovák J, Gazdag P, Kohajda Z, Gyökeres A, Györe B, Gurabi Z, Jost N, Virág L, Papp JG, Nagy N, Koncz I. Muscarinic agonists inhibit the ATP-dependent potassium current and suppress the ventricle-Purkinje action potential dispersion. Can J Physiol Pharmacol 2020; 99:247-253. [PMID: 33242286 DOI: 10.1139/cjpp-2020-0408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of the parasympathetic nervous system has been reported to have an antiarrhythmic role during ischemia-reperfusion injury by decreasing the arrhythmia triggers. Furthermore, it was reported that the parasympathetic neurotransmitter acetylcholine is able to modulate the ATP-dependent potassium current (I K-ATP), a crucial current activated during hypoxia. However, the possible significance of this current modulation in the antiarrhythmic mechanism is not fully clarified. Action potentials were measured using the conventional microelectrode technique from canine left ventricular papillary muscle and free-running Purkinje fibers, under normal and hypoxic conditions. Ionic currents were measured using the whole-cell configuration of the patch-clamp method. Acetylcholine at 5 μmol/L did not influence the action potential duration (APD) either in Purkinje fibers or in papillary muscle preparations. In contrast, it significantly lengthened the APD and suppressed the Purkinje-ventricle APD dispersion when it was administered after 5 μmol/L pinacidil application. Carbachol at 3 μmol/L reduced the pinacidil-activated I K-ATP under voltage-clamp conditions. Acetylcholine lengthened the ventricular action potential under simulated ischemia condition. In this study, we found that acetylcholine inhibits the I K-ATP and thus suppresses the ventricle-Purkinje APD dispersion. We conclude that parasympathetic tone may reduce the arrhythmogenic substrate exerting a complex antiarrhythmic mechanism during hypoxic conditions.
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Affiliation(s)
- Tibor Magyar
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Bence Pászti
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Noémi Tóth
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Jozefina Szlovák
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Péter Gazdag
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zsófia Kohajda
- MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Gyökeres
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Balázs Györe
- Faculty of Dentistry, University of Szeged, Hungary
| | - Zsolt Gurabi
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Julius Gy Papp
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - István Koncz
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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