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Abramochkin DV, Haworth TE, Kuzmin VS, Dzhumaniiazova I, Pustovit KB, Gacoin M, Shiels HA. Adrenergic prolongation of action potential duration in rainbow trout myocardium via inhibition of the delayed rectifier potassium current, I Kr. Comp Biochem Physiol A Mol Integr Physiol 2022; 267:111161. [PMID: 35143950 DOI: 10.1016/j.cbpa.2022.111161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 11/19/2022]
Abstract
Catecholamines mediate the 'fight or flight' response in a wide variety of vertebrates. The endogenous catecholamine adrenaline increases heart rate and contractile strength to raise cardiac output. The increase in contractile force is driven in large part by an increase in myocyte Ca2+ influx on the L-type Ca current (ICaL) during the cardiac action potential (AP). Here, we report a K+- based mechanism that prolongs AP duration (APD) in fish hearts following adrenergic stimulation. We show that adrenergic stimulation inhibits the delayed rectifier K+ current (IKr) in rainbow trout (Oncorhynchus mykiss) cardiomyocytes. This slows repolarization and prolongs APD which may contribute to positive inotropy following adrenergic stimulation in fish hearts. The endogenous ligand, adrenaline (1 μM), which activates both α- and β-ARs reduced maximal IKr tail current to 61.4 ± 3.9% of control in atrial and ventricular myocytes resulting in an APD prolongation of ~20% at both 50 and 90% repolarization. This effect was reproduced by the α-specific adrenergic agonist, phenylephrine (1 μM), but not the β-specific adrenergic agonist isoproterenol (1 μM). Adrenaline (1 μM) in the presence of β1 and β2-blockers (1 μM atenolol and 1 μM ICI-118551, respectively) also inhibited IKr. Thus, IKr suppression following α-adrenergic stimulation leads to APD prolongation in the rainbow trout heart. This is the first time this mechanism has been identified in fish and may act in unison with the well-known enhancement of ICaL following adrenergic stimulation to prolong APD and increase cardiac inotropy.
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Affiliation(s)
- Denis V Abramochkin
- Department of human and animal physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - T Eliot Haworth
- Faculty of Biological, Medical and Human Sciences, University of Manchester, Manchester M13 9NT, UK
| | - Vladislav S Kuzmin
- Department of human and animal physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Irina Dzhumaniiazova
- Department of human and animal physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Ksenia B Pustovit
- Department of human and animal physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Maeva Gacoin
- Faculty of Biological, Medical and Human Sciences, University of Manchester, Manchester M13 9NT, UK; Institut des Sciences Cognitives Marc Jeannerod, UMR5229 CNRS, Université de Lyon, 67 Boulevard Pinel, 69675 Bron Cedex, France
| | - Holly A Shiels
- Faculty of Biological, Medical and Human Sciences, University of Manchester, Manchester M13 9NT, UK.
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Badr A, Hassinen M, El-Sayed MF, Vornanen M. Effects of seasonal acclimatization on action potentials and sarcolemmal K+ currents in roach (Rutilus rutilus) cardiac myocytes. Comp Biochem Physiol A Mol Integr Physiol 2017; 205:15-27. [DOI: 10.1016/j.cbpa.2016.12.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 01/10/2023]
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Vornanen M. Electrical Excitability of the Fish Heart and Its Autonomic Regulation. FISH PHYSIOLOGY 2017. [DOI: 10.1016/bs.fp.2017.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Keen AN, Klaiman JM, Shiels HA, Gillis TE. Temperature-induced cardiac remodelling in fish. ACTA ACUST UNITED AC 2016; 220:147-160. [PMID: 27852752 PMCID: PMC5278617 DOI: 10.1242/jeb.128496] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Thermal acclimation causes the heart of some fish species to undergo significant remodelling. This includes changes in electrical activity, energy utilization and structural properties at the gross and molecular level of organization. The purpose of this Review is to summarize the current state of knowledge of temperature-induced structural remodelling in the fish ventricle across different levels of biological organization, and to examine how such changes result in the modification of the functional properties of the heart. The structural remodelling response is thought to be responsible for changes in cardiac stiffness, the Ca2+ sensitivity of force generation and the rate of force generation by the heart. Such changes to both active and passive properties help to compensate for the loss of cardiac function caused by a decrease in physiological temperature. Hence, temperature-induced cardiac remodelling is common in fish that remain active following seasonal decreases in temperature. This Review is organized around the ventricular phases of the cardiac cycle – specifically diastolic filling, isovolumic pressure generation and ejection – so that the consequences of remodelling can be fully described. We also compare the thermal acclimation-associated modifications of the fish ventricle with those seen in the mammalian ventricle in response to cardiac pathologies and exercise. Finally, we consider how the plasticity of the fish heart may be relevant to survival in a climate change context, where seasonal temperature changes could become more extreme and variable. Summary: Thermal acclimation of some temperate fishes causes extensive remodelling of the heart. The resultant changes to the active and passive properties of the heart represent a highly integrated phenotypic response.
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Affiliation(s)
- Adam N Keen
- Division of Cardiovascular Science, School of Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9NT, UK
| | - Jordan M Klaiman
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98109, USA
| | - Holly A Shiels
- Division of Cardiovascular Science, School of Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9NT, UK
| | - Todd E Gillis
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Vornanen M. The temperature dependence of electrical excitability in fish hearts. J Exp Biol 2016; 219:1941-52. [DOI: 10.1242/jeb.128439] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/17/2016] [Indexed: 01/08/2023]
Abstract
ABSTRACT
Environmental temperature has pervasive effects on the rate of life processes in ectothermic animals. Animal performance is affected by temperature, but there are finite thermal limits for vital body functions, including contraction of the heart. This Review discusses the electrical excitation that initiates and controls the rate and rhythm of fish cardiac contraction and is therefore a central factor in the temperature-dependent modulation of fish cardiac function. The control of cardiac electrical excitability should be sensitive enough to respond to temperature changes but simultaneously robust enough to protect against cardiac arrhythmia; therefore, the thermal resilience and plasticity of electrical excitation are physiological qualities that may affect the ability of fishes to adjust to climate change. Acute changes in temperature alter the frequency of the heartbeat and the duration of atrial and ventricular action potentials (APs). Prolonged exposure to new thermal conditions induces compensatory changes in ion channel expression and function, which usually partially alleviate the direct effects of temperature on cardiac APs and heart rate. The most heat-sensitive molecular components contributing to the electrical excitation of the fish heart seem to be Na+ channels, which may set the upper thermal limit for the cardiac excitability by compromising the initiation of the cardiac AP at high temperatures. In cardiac and other excitable cells, the different temperature dependencies of the outward K+ current and inward Na+ current may compromise electrical excitability at temperature extremes, a hypothesis termed the temperature-dependent depression of electrical excitation.
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Affiliation(s)
- Matti Vornanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, PO Box 111, Joensuu 80101, Finland
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Shiels HA, Galli GLJ, Block BA. Cardiac function in an endothermic fish: cellular mechanisms for overcoming acute thermal challenges during diving. Proc Biol Sci 2016; 282:20141989. [PMID: 25540278 DOI: 10.1098/rspb.2014.1989] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Understanding the physiology of vertebrate thermal tolerance is critical for predicting how animals respond to climate change. Pacific bluefin tuna experience a wide range of ambient sea temperatures and occupy the largest geographical niche of all tunas. Their capacity to endure thermal challenge is due in part to enhanced expression and activity of key proteins involved in cardiac excitation-contraction coupling, which improve cardiomyocyte function and whole animal performance during temperature change. To define the cellular mechanisms that enable bluefin tuna hearts to function during acute temperature change, we investigated the performance of freshly isolated ventricular myocytes using confocal microscopy and electrophysiology. We demonstrate that acute cooling and warming (between 8 and 28°C) modulates the excitability of the cardiomyocyte by altering the action potential (AP) duration and the amplitude and kinetics of the cellular Ca(2+) transient. We then explored the interactions between temperature, adrenergic stimulation and contraction frequency, and show that when these stressors are combined in a physiologically relevant way, they alter AP characteristics to stabilize excitation-contraction coupling across an acute 20°C temperature range. This allows the tuna heart to maintain consistent contraction and relaxation cycles during acute thermal challenges. We hypothesize that this cardiac capacity plays a key role in the bluefin tunas' niche expansion across a broad thermal and geographical range.
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Affiliation(s)
- H A Shiels
- Faculty of Life Sciences, The University of Manchester, Core Technology Facility, Grafton Street, Manchester M13 9PL, UK
| | - G L J Galli
- Faculty of Medical and Human Sciences, The University of Manchester, Core Technology Facility, Grafton Street, Manchester M13 9PL, UK
| | - B A Block
- Department of Biology, Tuna Research and Conservation Center, Stanford University, 120 Oceanview Boulevard, Pacific Grove, CA 93950, USA
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