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Smith B, Crossley DA, Wang T, Joyce W. No evidence for pericardial restraint in the snapping turtle (Chelydra serpentina) following pharmacologically-induced bradycardia at rest or during exercise. Am J Physiol Regul Integr Comp Physiol 2022; 322:R389-R399. [PMID: 35200048 PMCID: PMC9018006 DOI: 10.1152/ajpregu.00004.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Most animals elevate cardiac output during exercise through a rise in heart rate (fH), whilst stroke volume (VS) remains relatively unchanged. Cardiac pacing reveals that elevating fH alone does not alter cardiac output, which is instead largely regulated by the peripheral vasculature. In terms of myocardial oxygen demand, an increase in fH is more costly than that which would incur if VS instead were to increase. We hypothesized that fH must increase because any substantial rise in VS would be constrained by the pericardium. To investigate this hypothesis, we explored the effects of pharmacologically-induced bradycardia, with ivabradine treatment, on VS at rest and during exercise in the common snapping turtle (Chelydra serpentina) with intact or opened pericardium. We first showed that, in isolated myocardial preparations, ivabradine exerted a pronounced positive inotropic effect on atrial tissue, but only minor effects on ventricle. Ivabradine reduced fH in vivo, such that exercise tachycardia was attenuated. Pulmonary and systemic VS rose in response to ivabradine. The rise in pulmonary VS largely compensated for the bradycardia at rest, leaving total pulmonary flow unchanged by ivabradine, although ivabradine reduced pulmonary blood flow during swimming (exercise x ivabradine interaction, P<0.05). Although systemic VS increased, systemic blood flow was reduced by ivabradine both at rest and during exercise, in spite of ivabradine's potential to increase cardiac contractility. Opening the pericardium had no effect on fH, VS or blood flows before or after ivabradine, indicating that the pericardium does not constrain VS in turtles, even during pharmacologically-induced bradycardia.
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Affiliation(s)
- Brandt Smith
- Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Tobias Wang
- Department of Biology- Zoophysiology, Aarhus University, Aarhus C, Denmark
| | - William Joyce
- Department of Biology- Zoophysiology, Aarhus University, Aarhus C, Denmark
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2
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Filatova TS, Abramochkin DV, Pavlova NS, Pustovit KB, Konovalova OP, Kuzmin VS, Dobrzynski H. Repolarizing potassium currents in working myocardium of Japanese quail: a novel translational model for cardiac electrophysiology. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110919. [DOI: 10.1016/j.cbpa.2021.110919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/06/2021] [Accepted: 02/06/2021] [Indexed: 12/14/2022]
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3
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Lopes AG, Monteiro DA, Kalinin AL. Effects of change in temperature on the cardiac contractility of broad-snouted caiman (Caiman latirostris) during digestion. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:417-425. [PMID: 33773091 DOI: 10.1002/jez.2457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/07/2022]
Abstract
In many reptiles, digestion has been associated with the selection of higher body temperatures, the so-called post-prandial thermophilic response. This study aimed to investigate the excitation-contraction (E-C) coupling in postprandial broad-snouted caimans (Caiman latirostris) in response to acute warming within a preferred body temperature range of crocodiles. Isometric preparations subjected to a temperature transition from 25°C to 30°C were used to investigate myocardial contractility of postprandial caimans, that is, 48 h after the animals ingested a rodent meal corresponding to 15% of body mass. The caiman heart exhibits a negative force-frequency relationship that is independent of the temperature. At 25°C, cardiac muscle was able to maintain a constant force up to 36 bpm, above which it decreased significantly, reaching minimum values at the highest frequency of 84 bpm. Moreover, E-C coupling is predominantly dependent on transsarcolemmal Ca2+ transport denoted by the lack of significant ryanodine effects on force generation. On the contrary, ventricular strips at 30°C were able to sustain the cardiac contractility at higher pacing frequencies (from 12 to 144 bpm) due to an important role of Na+ /Ca2+ exchanger in Ca2+ cycling, as indicated by the decay of the post-rest contraction, and a significant contribution of the sarcoplasmic reticulum above 72 bpm. Our results demonstrated that the myocardium of postprandial caimans exhibits a significant degree of thermal plasticity of E-C coupling during acute warming. Therefore, myocardial contractility can be maximized when postprandial broad-snouted caimans select higher body temperatures (preferred temperature zone) following feeding.
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Affiliation(s)
- André G Lopes
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil.,Joint Graduate Program in Physiological Sciences, Federal University of São Carlos-UFSCar/São Paulo State University, UNESP Campus Araraquara, Araraquara, São Paulo, Brazil
| | - Diana A Monteiro
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
| | - Ana L Kalinin
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
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Folkerts EJ, Heuer RM, Flynn S, Stieglitz JD, Benetti DD, Alessi DS, Goss GG, Grosell M. Exposure to Hydraulic Fracturing Flowback Water Impairs Mahi-Mahi ( Coryphaena hippurus) Cardiomyocyte Contractile Function and Swimming Performance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13579-13589. [PMID: 33138383 DOI: 10.1021/acs.est.0c02719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Publicly available toxicological studies on wastewaters associated with unconventional oil and gas (UOG) activities in offshore regions are nonexistent. The current study investigated the impact of hydraulic fracturing-generated flowback water (HF-FW) on whole organism swimming performance/respiration and cardiomyocyte contractility dynamics in mahi-mahi (Coryphaena hippurus-hereafter referred to as "mahi"), an organism which inhabits marine ecosystems where offshore hydraulic fracturing activity is intensifying. Following exposure to 2.75% HF-FW for 24 h, mahi displayed significantly reduced critical swimming speeds (Ucrit) and aerobic scopes (reductions of ∼40 and 61%, respectively) compared to control fish. Additionally, cardiomyocyte exposures to the same HF-FW sample at 2% dilutions reduced a multitude of mahi sarcomere contraction properties at various stimulation frequencies compared to all other treatment groups, including an approximate 40% decrease in sarcomere contraction size and a nearly 50% reduction in sarcomere relaxation velocity compared to controls. An approximate 8-fold change in expression of the cardiac contractile regulatory gene cmlc2 was also seen in ventricles from 2.75% HF-FW-exposed mahi. These results collectively identify cardiac function as a target for HF-FW toxicity and provide some of the first published data on UOG toxicity in a marine species.
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Affiliation(s)
- Erik J Folkerts
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Rachael M Heuer
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, United States
| | - Shannon Flynn
- School of Natural and Environmental Science, Newcastle University, Newcastle Upon Tyne NE1 7RU, U.K
| | - John D Stieglitz
- Department of Marine Ecosystems and Society, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, United States
| | - Daniel D Benetti
- Department of Marine Ecosystems and Society, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, United States
| | - Daniel S Alessi
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
| | - Greg G Goss
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
- National Research Council Nanotechnology Initiative, Edmonton, Alberta T6G 2M9, Canada
| | - Martin Grosell
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, United States
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Heuer RM, Galli GLJ, Shiels HA, Fieber LA, Cox GK, Mager EM, Stieglitz JD, Benetti DD, Grosell M, Crossley Ii DA. Impacts of Deepwater Horizon Crude Oil on Mahi-Mahi ( Coryphaena hippurus) Heart Cell Function. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9895-9904. [PMID: 31343865 DOI: 10.1021/acs.est.9b03798] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Deepwater Horizon crude oil is comprised of polycyclic aromatic hydrocarbons that cause a number of cardiotoxic effects in marine fishes across all levels of biological organization and at different life stages. Although cardiotoxic impacts have been widely reported, the mechanisms underlying these impairments in adult fish remain understudied. In this study, we examined the impacts of crude oil on cardiomyocyte contractility and electrophysiological parameters in freshly isolated ventricular cardiomyocytes from adult mahi-mahi (Coryphaena hippurus). Cardiomyocytes directly exposed to oil exhibited reduced contractility over a range of environmentally relevant concentrations (2.8-12.9 μg l-1∑PAH). This reduction in contractility was most pronounced at higher stimulation frequencies, corresponding to the upper limits of previously measured in situ mahi heart rates. To better understand the mechanisms underlying impaired contractile function, electrophysiological studies were performed, which revealed oil exposure prolonged cardiomyocyte action potentials and disrupted potassium cycling (9.9-30.4 μg l-1∑PAH). This study is the first to measure cellular contractility in oil-exposed cardiomyocytes from a pelagic fish. Results from this study contribute to previously observed impairments to heart function and whole-animal exercise performance in mahi, underscoring the advantages of using an integrative approach in examining mechanisms of oil-induced cardiotoxicity in marine fish.
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Affiliation(s)
- Rachael M Heuer
- Department of Biological Sciences , University of North Texas , 1511 W. Sycamore Street , Denton Texas 76203 , United States
- Department of Marine Biology and Ecology , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - Gina L J Galli
- University of Manchester, Faculty of Biology, Medicine and Health Sciences , The University of Manchester, Core Technology Facility , Grafton Street , Manchester M13 9PL , U.K
| | - Holly A Shiels
- University of Manchester, Faculty of Biology, Medicine and Health Sciences , The University of Manchester, Core Technology Facility , Grafton Street , Manchester M13 9PL , U.K
| | - Lynne A Fieber
- Department of Marine Biology and Ecology , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - Georgina K Cox
- Department of Marine Biology and Ecology , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
- Department of Integrative Biology , University of Guelph , 50 Stone Road East , Guelph , Ontario Canada , N1G 2W1
| | - Edward M Mager
- Department of Biological Sciences , University of North Texas , 1511 W. Sycamore Street , Denton Texas 76203 , United States
- Department of Marine Biology and Ecology , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - John D Stieglitz
- Department of Marine Ecosystems and Society , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - Daniel D Benetti
- Department of Marine Ecosystems and Society , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - Martin Grosell
- Department of Marine Biology and Ecology , University of Miami Rosenstiel School of Marine and Atmospheric Science , 4600 Rickenbacker Causeway , Miami , Florida 33149 , United States
| | - Dane A Crossley Ii
- Department of Biological Sciences , University of North Texas , 1511 W. Sycamore Street , Denton Texas 76203 , United States
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6
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The electrocardiogram of vertebrates: Evolutionary changes from ectothermy to endothermy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 144:16-29. [DOI: 10.1016/j.pbiomolbio.2018.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 12/11/2022]
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7
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Fanter CE, Campbell KS, Warren DE. The effects of pH and P i on tension and Ca 2+ sensitivity of ventricular myofilaments from the anoxia-tolerant painted turtle. ACTA ACUST UNITED AC 2017; 220:4234-4241. [PMID: 28939564 DOI: 10.1242/jeb.164137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/17/2017] [Indexed: 11/20/2022]
Abstract
We aimed to determine how increases in intracellular H+ and inorganic phosphate (Pi) to levels observed during anoxic submergence affect contractility in ventricular muscle of the anoxia-tolerant Western painted turtle, Chrysemys picta bellii Skinned multicellular preparations were exposed to six treatments with physiologically relevant levels of pH (7.4, 7.0, 6.6) and Pi (3 and 8 mmol l-1). Each preparation was tested in a range of calcium concentrations (pCa 9.0-4.5) to determine the pCa-tension relationship for each treatment. Acidosis significantly decreased contractility by decreasing Ca2+ sensitivity (pCa50) and tension development (P<0.001). Increasing [Pi] also decreased contractility by decreasing tension development at every pH level (P<0.001) but, alone, did not affect Ca2+ sensitivity (P=0.689). Simultaneous increases in [H+] and [Pi] interacted to attenuate the decreased tension development and Ca2+ sensitivity (P<0.001), possibly reflecting a decreased sensitivity to Pi when it is present as the dihydrogen phosphate form, which increases as pH decreases. Compared with that of mammals, the ventricle of turtles exhibits higher Ca2+ sensitivity, which is consistent with previous studies of ectothermic vertebrates.
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Affiliation(s)
- Cornelia E Fanter
- Department of Biology, Saint Louis University, St Louis, MO 63109, USA
| | - Kenneth S Campbell
- University of Kentucky, Department of Physiology and Division of Cardiovascular Medicine, Lexington, KY 40536, USA
| | - Daniel E Warren
- Department of Biology, Saint Louis University, St Louis, MO 63109, USA
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8
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Young BA, Dumais J, John N, Lyons B, Macduff A, Most M, Reiser NA, Reiser PJ. Functional Segregation within the Muscles of Aquatic Propulsion in the Asiatic Water Monitor (Varanus salvator). Front Physiol 2016; 7:380. [PMID: 27660612 PMCID: PMC5014869 DOI: 10.3389/fphys.2016.00380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/22/2016] [Indexed: 11/26/2022] Open
Abstract
Water monitor lizards (Varanus salvator) swim using sinusoidal oscillations generated at the base of their long (50% of total body length) tail. In an effort to determine which level of the structural/organizational hierarchy of muscle is associated with functional segregation between the muscles of the tail base, an array of muscle features-myosin heavy chain profiles, enzymatic fiber types, twitch and tetanic force production, rates of fatigue, muscle compliance, and electrical activity patterns-were quantitated. The two examined axial muscles, longissimus, and iliocaudalis, were generally similar at the molecular, biochemical, and physiological levels, but differed at the biomechanics level and in their activation pattern. The appendicular muscle examined, caudofemoralis, differed from the axial muscles particularly at the molecular and physiological levels, and it exhibited a unique compliance profile and pattern of electrical activation. There were some apparent contradictions between the different structural/organizational levels examined. These contradictions, coupled with a unique myosin heavy chain profile, lead to the hypothesis that there are previously un-described molecular/biochemical specializations within varanid skeletal muscles.
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Affiliation(s)
- Bruce A. Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University of Health SciencesKirksville, MO, USA
| | - Jessica Dumais
- Department of Physical Therapy, University of Massachusetts LowellLowell, MA, USA
| | - Nicholas John
- Department of Physical Therapy, University of Massachusetts LowellLowell, MA, USA
| | - Brandon Lyons
- Department of Physical Therapy, University of Massachusetts LowellLowell, MA, USA
| | - Andrew Macduff
- Department of Physical Therapy, University of Massachusetts LowellLowell, MA, USA
| | - Matthew Most
- Department of Physical Therapy, University of Massachusetts LowellLowell, MA, USA
| | - Nathan A. Reiser
- Department of Biosciences, College of Dentistry, Ohio State UniversityColumbus, OH, USA
| | - Peter J. Reiser
- Department of Biosciences, College of Dentistry, Ohio State UniversityColumbus, OH, USA
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9
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Jensen B, Moorman AFM, Wang T. Structure and function of the hearts of lizards and snakes. Biol Rev Camb Philos Soc 2013; 89:302-36. [DOI: 10.1111/brv.12056] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 06/26/2013] [Accepted: 07/30/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Bjarke Jensen
- Department of Bioscience, Zoophysiology; Aarhus University; Aarhus C 8000 Denmark
- Department of Anatomy, Embryology & Physiology, Academic Medical Center; University of Amsterdam; Amsterdam 1105 The Netherlands
| | - Antoon F. M. Moorman
- Department of Anatomy, Embryology & Physiology, Academic Medical Center; University of Amsterdam; Amsterdam 1105 The Netherlands
| | - Tobias Wang
- Department of Bioscience, Zoophysiology; Aarhus University; Aarhus C 8000 Denmark
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Cerra MC, Imbrogno S. Phospholamban and cardiac function: a comparative perspective in vertebrates. Acta Physiol (Oxf) 2012; 205:9-25. [PMID: 22463608 DOI: 10.1111/j.1748-1716.2012.02389.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phospholamban (PLN) is a small phosphoprotein closely associated with the cardiac sarcoplasmic reticulum (SR). Dephosphorylated PLN tonically inhibits the SR Ca-ATPase (SERCA2a), while phosphorylation at Ser16 by PKA and Thr17 by Ca(2+) /calmodulin-dependent protein kinase (CaMKII) relieves the inhibition, and this increases SR Ca(2+) uptake. For this reason, PLN is one of the major determinants of cardiac contractility and relaxation. In this review, we attempted to highlight the functional significance of PLN in vertebrate cardiac physiology. We will refer to the huge literature on mammals in order to describe the molecular characteristics of this protein, its interaction with SERCA2a and its role in the regulation of the mechanic and the electric performance of the heart under basal conditions, in the presence of chemical and physical stresses, such as β-adrenergic stimulation, response to stretch, force-frequency relationship and intracellular acidosis. Our aim is to provide the basis to discuss the role of PLN also on the cardiac function of nonmammalian vertebrates, because so far this aspect has been almost neglected. Accordingly, when possible, the literature on PLN will be analysed taking into account the nonuniform cardiac structural and functional characteristics encountered in ectothermic vertebrates, such as the peculiar and variable organization of the SR, the large spectrum of response to stresses and the disaptive absence of crucial proteins (i.e. haemoglobinless and myoglobinless species).
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Affiliation(s)
| | - S. Imbrogno
- Department of Cell Biology; University of Calabria; Arcavacata di Rende (CS); Italy
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Cerra MC, Imbrogno S. Phospholamban and cardiac function: a comparative perspective in vertebrates. Acta Physiol (Oxf) 2012. [DOI: 10.1111/j.1748-1716.2011.02389.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - S. Imbrogno
- Department of Cell Biology; University of Calabria; Arcavacata di Rende (CS); Italy
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