1
|
Zena LA, Ekström AT, Morgenroth D, McArley T, Axelsson M, Sundh H, Palmquist A, Johansen IB, Gräns A, Sandblom E. Beating the heart failure odds: long-term survival after myocardial ischemia in juvenile rainbow trout. Am J Physiol Regul Integr Comp Physiol 2024; 326:R484-R498. [PMID: 38406842 PMCID: PMC11381025 DOI: 10.1152/ajpregu.00005.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Salmonid fish include some of the most valued cultured fish species worldwide. Unlike most other fish, the hearts of salmonids, including Atlantic salmon and rainbow trout, have a well-developed coronary circulation. Consequently, their hearts' reliance on oxygenation through coronary arteries leaves them prone to coronary lesions, believed to precipitate myocardial ischemia. Here, we mimicked such coronary lesions by subjecting groups of juvenile rainbow trout to coronary ligation, assessing histomorphological myocardial changes associated with ischemia and scarring in the context of cardiac arrhythmias using electrocardiography (ECG). Notable ECG changes resembling myocardial ischemia-like ECG in humans, such as atrioventricular blocks and abnormal ventricular depolarization (prolonged and fragmented QRS complex), as well as repolarization (long QT interval) patterns, were observed during the acute phase of myocardial ischemia. A remarkable 100% survival rate was observed among juvenile trout subjected to coronary ligation after 24 wk. Recovery from coronary ligation occurred through adaptive ventricular remodeling, coupled with a fast cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health in salmonid fish, a family particularly susceptible to cardiac diseases. Furthermore, our results provide valuable insights into comparative studies on the evolution, pathophysiology, and ontogeny of vertebrate cardiac repair and restoration.NEW & NOTEWORTHY Juvenile rainbow trout exhibit a remarkable capacity to recover from cardiac injury caused by myocardial ischemia. Recovery from cardiac damage occurs through adaptive ventricular remodeling, coupled with a rapid cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health within salmonid fishes, which are particularly susceptible to cardiac diseases.
Collapse
Affiliation(s)
- Lucas A Zena
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Gothenburg, Sweden
| | - Andreas T Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anders Palmquist
- Department of Biomaterials, University of Gothenburg, Gothenburg, Sweden
| | - Ida B Johansen
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Albin Gräns
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
2
|
Guagnoni IN, Last KB, Rindom E, Wang T. The pancreas does not contribute to the non-adrenergic-non-cholinergic stimulation of heart rate in digesting pythons. Comp Biochem Physiol A Mol Integr Physiol 2024; 291:111608. [PMID: 38373589 DOI: 10.1016/j.cbpa.2024.111608] [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: 01/08/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
Vertebrates elevate heart rate when metabolism increases during digestion. Part of this tachycardia is due to a non-adrenergic-non-cholinergic (NANC) stimulation of the cardiac pacemaker, and it has been suggested these NANC factors are circulating hormones that are released from either gastrointestinal or endocrine glands. The NANC stimulation is particularly pronounced in species with large metabolic responses to digestion, such as reptiles. To investigate the possibility that the pancreas may release hormones that exert positive chronotropic effects on the digesting Burmese python heart, a species with very large postprandial changes in heart rate and oxygen uptake, we evaluate how pancreatectomy affects postprandial heart rate before and after autonomic blockade of the muscarinic and the beta-adrenergic receptors. We also measured the rates of oxygen consumption and evaluated the short-term control of the heart using the spectral analysis of heart rate variability and the baroreflex sequence method. Digestion caused the ubiquitous tachycardia, but the intrinsic heart rate (revealed after the combination of atropine and propranolol) was not affected by pancreatectomy and therefore hormones, such as glucagon and insulin, do not appear to contribute to the regulation of heart rate during digestion in Burmese pythons.
Collapse
Affiliation(s)
- Igor Noll Guagnoni
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark; Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil.
| | - Katja Bundgaard Last
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Emil Rindom
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Tobias Wang
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
3
|
Guagnoni IN, Armelin VA, da Silva Braga VH, Monteiro DA, Florindo LH. Cardiovascular responses and the role of the neurohumoral cardiac regulation during digestion in the herbivorous lizard Iguana iguana. J Exp Biol 2024; 227:jeb247105. [PMID: 38186316 DOI: 10.1242/jeb.247105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 12/27/2023] [Indexed: 01/09/2024]
Abstract
Carnivorous reptiles exhibit an intense metabolic increment during digestion, which is accompanied by several cardiovascular adjustments responsible for meeting the physiological demands of the gastrointestinal system. Postprandial tachycardia, a well-documented phenomenon in these animals, is mediated by the withdrawal of vagal tone associated with the chronotropic effects of non-adrenergic and non-cholinergic (NANC) factors. However, herbivorous reptiles exhibit a modest metabolic increment during digestion and there is no information about postprandial cardiovascular adjustments. Considering the significant impact of feeding characteristics on physiological responses, we investigated cardiovascular and metabolic responses, as well as the neurohumoral mechanisms of cardiac control, in the herbivorous lizard Iguana iguana during digestion. We measured oxygen consumption rate (O2), heart rate (fH), mean arterial blood pressure (MAP), myocardial activity, cardiac autonomic tone, fH/MAP variability and baroreflex efficiency in both fasting and digesting animals before and after parasympathetic blockade with atropine followed by double autonomic blockade with atropine and propranolol. Our results revealed that the peak of O2 in iguanas was reached 24 h after feeding, accompanied by an increase in myocardial activity and a subtle tachycardia mediated exclusively by a reduction in cardiac parasympathetic activity. This represents the first reported case of postprandial tachycardia in digesting reptiles without the involvement of NANC factors. Furthermore, this withdrawal of vagal stimulation during digestion may reduce the regulatory range for short-term fH adjustments, subsequently intensifying the blood pressure variability as a consequence of limiting baroreflex efficiency.
Collapse
Affiliation(s)
- Igor Noll Guagnoni
- Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - FAPESP/CNPq), São Paulo, SP 13506-900, Brazil
| | - Vinicius Araújo Armelin
- Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - FAPESP/CNPq), São Paulo, SP 13506-900, Brazil
- Department of Physiology, Institute of Biosciences (IB), University of São Paulo (USP), São Paulo, SP 05508-090, Brazil
| | - Victor Hugo da Silva Braga
- Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - FAPESP/CNPq), São Paulo, SP 13506-900, Brazil
| | - Diana Amaral Monteiro
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Rodovia Washington Luiz, km 235, São Carlos, SP 13565-905, Brazil
| | - Luiz Henrique Florindo
- Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - FAPESP/CNPq), São Paulo, SP 13506-900, Brazil
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Rodovia Washington Luiz, km 235, São Carlos, SP 13565-905, Brazil
| |
Collapse
|
4
|
Joyce W, Warwicker J, Shiels HA, Perry SF. Evolution and divergence of teleost adrenergic receptors: why sometimes 'the drugs don't work' in fish. J Exp Biol 2023; 226:jeb245859. [PMID: 37823524 DOI: 10.1242/jeb.245859] [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] [Indexed: 10/13/2023]
Abstract
Adrenaline and noradrenaline, released as hormones and/or neurotransmitters, exert diverse physiological functions in vertebrates, and teleost fishes are widely used as model organisms to study adrenergic regulation; however, such investigations often rely on receptor subtype-specific pharmacological agents (agonists and antagonists; see Glossary) developed and validated in mammals. Meanwhile, evolutionary (phylogenetic and comparative genomic) studies have begun to unravel the diversification of adrenergic receptors (ARs) and reveal that whole-genome duplications and pseudogenization events in fishes results in notable distinctions from mammals in their genomic repertoire of ARs, while lineage-specific gene losses within teleosts have generated significant interspecific variability. In this Review, we visit the evolutionary history of ARs (including α1-, α2- and β-ARs) to highlight the prominent interspecific differences in teleosts, as well as between teleosts and other vertebrates. We also show that structural modelling of teleost ARs predicts differences in ligand binding affinity compared with mammalian orthologs. To emphasize the difficulty of studying the roles of different AR subtypes in fish, we collate examples from the literature of fish ARs behaving atypically compared with standard mammalian pharmacology. Thereafter, we focus on specific case studies of the liver, heart and red blood cells, where our understanding of AR expression has benefited from combining pharmacological approaches with molecular genetics. Finally, we briefly discuss the ongoing advances in 'omics' technologies that, alongside classical pharmacology, will provide abundant opportunities to further explore adrenergic signalling in teleosts.
Collapse
Affiliation(s)
- William Joyce
- Department of Biology - Zoophysiology, Aarhus University, 8000 Aarhus C, Denmark
| | - Jim Warwicker
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, Manchester Institute of Biotechnology, The University of Manchester, Manchester, M1 7DN, UK
| | - Holly A Shiels
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PL, UK
| | - Steve F Perry
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| |
Collapse
|
5
|
Thermal acclimation and acute temperature effects on cardiac barostatic reflexes in rainbow trout (Oncorhynchus mykiss). J Therm Biol 2022; 109:103315. [DOI: 10.1016/j.jtherbio.2022.103315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/26/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
|
6
|
Porter E, Clow K, Sandrelli R, Gamperl A. Acute and chronic cold exposure differentially affect cardiac control, but not cardiorespiratory function, in resting Atlantic salmon (S almo salar). Curr Res Physiol 2022; 5:158-170. [PMID: 35359619 PMCID: PMC8960890 DOI: 10.1016/j.crphys.2022.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/19/2022] [Accepted: 03/14/2022] [Indexed: 02/07/2023] Open
Abstract
No studies have examined the effects of cold temperatures (∼0-1 °C) on in vivo cardiac function and control, and metabolism, in salmonids. Thus, we examined: 1) how acclimation to 8 °C vs. acclimation (>3 weeks) or acute exposure (8-1 °C at 1 °C h-1) to 1 °C influenced cardiorespiratory parameters in resting Atlantic salmon; and 2) if/how the control of cardiac function was affected. Oxygen consumption ( M ˙ O 2 ) and cardiac function [i.e., heart rate (f H) and cardiac output (Q ˙ ) ] were 50% lower in the acutely cooled and 1oC-acclimated salmon as compared to 8 °C fish, whereas stroke volume (VS) was unchanged. Intrinsic f H was not affected by whether the fish were acutely exposed or acclimated to 1 °C (values ∼51, 24 and 21 beats min-1 in 8 and 1 °C-acclimated fish, and 8-1 °C fish, respectively), and in all groups f H was primarily under adrenergic control/tone (cholinergic tone 13-18%; adrenergic tone 37-70%). However, β-adrenergic blockade resulted in a 50% increase in VS in the 1oC-acclimated group, and this was surprising as circulating catecholamine levels were ∼1-3 nM in all groups. Overall, the data suggest that this species has a limited capacity to acclimate to temperatures approaching 0 °C. However, we cannot exclude the possibility that cardiac and metabolic responses are evoked when salmon are cooled to ∼ 0-1 °C, and that this prevented further declines in these parameters (i.e., they 'reset' quickly). Our data also provide further evidence that VS is temperature insensitive, and strongly suggest that changes in adrenoreceptor mediated control of venous pressure/capacitance occur when salmon are acclimated to 1 °C.
Collapse
Affiliation(s)
- E.S. Porter
- Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada
| | - K.A. Clow
- Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada
| | - R.M. Sandrelli
- Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada
| | - A.K. Gamperl
- Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada
| |
Collapse
|
7
|
Joyce W, Wang T. Regulation of heart rate in vertebrates during hypoxia: A comparative overview. Acta Physiol (Oxf) 2022; 234:e13779. [PMID: 34995393 DOI: 10.1111/apha.13779] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/12/2021] [Accepted: 01/01/2022] [Indexed: 12/18/2022]
Abstract
Acute exposure to low oxygen (hypoxia) places conflicting demands on the heart. Whilst an increase in heart rate (tachycardia) may compensate systemic oxygen delivery as arterial oxygenation falls, the heart itself is an energetically expensive organ that may benefit from slowing (bradycardia) to reduce work when oxygen is limited. Both strategies are apparent in vertebrates, with tetrapods (mammals, birds, reptiles, and amphibians) classically exhibiting hypoxic tachycardia and fishes displaying characteristic hypoxic bradycardia. With a richer understanding of the ontogeny and evolution of the responses, however, we see similarities in the underlying mechanisms between vertebrate groups. For example, in adult mammals, primary bradycardia results from the hypoxic stimulation of carotid body chemoreceptors that are overwhelmed by mechano-sensory feedback from the lung associated with hyperpnoea. Fish-like bradycardia prevails in the mammalian foetus (which, at this stage, is incapable of pulmonary ventilation), and in fish and foetus alike, the bradycardia ensues despite an elevation of circulating catecholamines. In both cases, the reduced heart rate may primarily serve to protect the heart. Thus, the comparative perspective offers fundamental insight into how and why different vertebrates regulate heart rate in different ways during periods of hypoxia.
Collapse
Affiliation(s)
- William Joyce
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
| | - Tobias Wang
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
| |
Collapse
|
8
|
Mignucci A, Bourjea J, Forget F, Allal H, Dutto G, Gasset E, McKenzie DJ. Cardiac and behavioural responses to hypoxia and warming in free-swimming gilthead seabream, Sparus aurata. J Exp Biol 2021; 224:271040. [PMID: 34308993 DOI: 10.1242/jeb.242397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/16/2021] [Indexed: 11/20/2022]
Abstract
Gilthead seabream were equipped with intraperitoneal biologging tags to investigate cardiac responses to hypoxia and warming, comparing when fish were either swimming freely in a tank with conspecifics or confined to individual respirometers. After tag implantation under anaesthesia, heart rate (fH) required 60 h to recover to a stable value in a holding tank. Subsequently, when undisturbed under control conditions (normoxia, 21°C), mean fH was always significantly lower in the tank than in the respirometers. In progressive hypoxia (100% to 15% oxygen saturation), mean fH in the tank was significantly lower than in the respirometers at oxygen levels down to 40%, with significant bradycardia in both holding conditions below this level. Simultaneous logging of tri-axial body acceleration revealed that spontaneous activity, inferred as the variance of external acceleration (VARm), was low and invariant in hypoxia. Warming (21 to 31°C) caused progressive tachycardia with no differences in fH between holding conditions. Mean VARm was, however, significantly higher in the tank during warming, with a positive relationship between VARm and fH across all temperatures. Therefore, spontaneous activity contributed to raising fH of fish in the tank during warming. Mean fH in respirometers had a highly significant linear relationship with mean rates of oxygen uptake, considering data from hypoxia and warming together. The high fH of confined seabream indicates that respirometry techniques may bias estimates of metabolic traits in some fishes, and that biologging on free-swimming fish will provide more reliable insight into cardiac and behavioural responses to environmental stressors by fish in their natural environment.
Collapse
Affiliation(s)
- Alexandre Mignucci
- MARBEC, Université de Montpelier, CNRS, IRD, Ifremer, 34200 Sète, France
| | - Jérôme Bourjea
- MARBEC, Université de Montpelier, CNRS, IRD, Ifremer, 34200 Sète, France
| | - Fabien Forget
- MARBEC, Université de Montpelier, CNRS, IRD, Ifremer, 34200 Sète, France
| | - Hossein Allal
- CHU de Montpellier, Service Chirurgie Pédiatrique, 34000 Montpellier, France
| | - Gilbert Dutto
- MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 34250, Palavas-les-Flots, France
| | - Eric Gasset
- MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 34250, Palavas-les-Flots, France
| | - David J McKenzie
- MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 34095 Montpellier, France
| |
Collapse
|
9
|
Adrenergic tone benefits cardiac performance and warming tolerance in two teleost fishes that lack a coronary circulation. J Comp Physiol B 2021; 191:701-709. [PMID: 33738526 PMCID: PMC8241749 DOI: 10.1007/s00360-021-01359-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/04/2021] [Accepted: 02/22/2021] [Indexed: 01/14/2023]
Abstract
Tolerance to acute environmental warming in fish is partly governed by the functional capacity of the heart to increase systemic oxygen delivery at high temperatures. However, cardiac function typically deteriorates at high temperatures, due to declining heart rate and an impaired capacity to maintain or increase cardiac stroke volume, which in turn has been attributed to a deterioration of the electrical conductivity of cardiac tissues and/or an impaired cardiac oxygen supply. While autonomic regulation of the heart may benefit cardiac function during warming by improving myocardial oxygenation, contractility and conductivity, the role of these processes for determining whole animal thermal tolerance is not clear. This is in part because interpretations of previous pharmacological in vivo experiments in salmonids are ambiguous and were confounded by potential compensatory increases in coronary oxygen delivery to the myocardium. Here, we tested the previously advanced hypothesis that cardiac autonomic control benefits heart function and acute warming tolerance in perch (Perca fluviatilis) and roach (Rutilus rutilus); two species that lack coronary arteries and rely entirely on luminal venous oxygen supplies for cardiac oxygenation. Pharmacological blockade of β-adrenergic tone lowered the upper temperature where heart rate started to decline in both species, marking the onset of cardiac failure, and reduced the critical thermal maximum (CTmax) in perch. Cholinergic (muscarinic) blockade had no effect on these thermal tolerance indices. Our findings are consistent with the hypothesis that adrenergic stimulation improves cardiac performance during acute warming, which, at least in perch, increases acute thermal tolerance.
Collapse
|
10
|
Nørgaard S, Joyce W, Jensen MF, Enok S, Skovgaard N, Wang T. Histamine exerts both direct H 2-mediated and indirect catecholaminergic effects on heart rate in pythons. J Comp Physiol B 2021; 191:347-355. [PMID: 33474644 DOI: 10.1007/s00360-020-01338-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/22/2020] [Accepted: 12/30/2020] [Indexed: 11/25/2022]
Abstract
The vertebrate heart is regulated by excitatory adrenergic and inhibitory cholinergic innervations, as well as non-adrenergic non-cholinergic (NANC) factors that may be circulating in the blood or released from the autonomic nerves. As an example of NANC signaling, an increased histaminergic tone, acting through stimulation of H2 receptors, contributes markedly to the rise in heart rate during digestion in pythons. In addition to the direct effects of histamine, it is also known that histamine can reinforce the cholinergic and adrenergic signaling. Thus, to further our understanding of the histaminergic regulation of the cardiovascular response in pythons, we designed a series of in vivo experiments complemented by in vitro experiments on sinoatrial and vascular ring preparations. We demonstrate the tachycardic mechanism of histamine works partly through a direct binding of cardiac H2 receptors and in part through a myocardial histamine-induced catecholamine release, which strengthens the sympathetic adrenergic signaling pathway.
Collapse
Affiliation(s)
- Simon Nørgaard
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark
| | - William Joyce
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark
| | - Maja Fuhlendorff Jensen
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark
| | - Sanne Enok
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark
| | - Nini Skovgaard
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark
| | - Tobias Wang
- Department of Biology, Aarhus University, C.F. Møllers Allé 3, building 1131, 8000, Aarhus C, Denmark.
| |
Collapse
|
11
|
Guagnoni IN, Armelin VA, da Silva Braga VH, Rantin FT, Florindo LH. Postprandial cardiorespiratory responses and the regulation of digestion-associated tachycardia in Nile tilapia (Oreochromis niloticus). J Comp Physiol B 2020; 191:55-67. [PMID: 33005989 DOI: 10.1007/s00360-020-01317-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 08/29/2020] [Accepted: 09/20/2020] [Indexed: 11/25/2022]
Abstract
Cardiorespiratory adjustments that occur after feeding are essential to supply the demands of digestion in vertebrates. The well-documented postprandial tachycardia is triggered by an increase in adrenergic activity and by non-adrenergic non-cholinergic (NANC) factors in mammals and crocodilians, while it is linked to a withdrawal of vagal drive and NANC factors in non-crocodilian ectotherms-except for fish, in which the sole investigation available indicated no participation of NANC factors. On the other hand, postprandial ventilatory adjustments vary widely among air-breathing vertebrates, with different species exhibiting hyperventilation, hypoventilation, or even no changes at all. Regarding fish, which live in an environment with low oxygen capacitance that requires great ventilatory effort for oxygen uptake, data on the ventilatory consequences of feeding are also scarce. Thus, the present study sought to investigate the postprandial cardiorespiratory adjustments and the mediation of digestion-associated tachycardia in the unimodal water-breathing teleost Oreochromis niloticus. Heart rate (fH), cardiac autonomic tones, ventilation rate (fV), ventilation amplitude, total ventilation and fH/fV variability were assessed both in fasting and digesting animals under untreated condition, as well as after muscarinic cholinergic blockade with atropine and double autonomic blockade with atropine and propranolol. The results revealed that digestion was associated with marked tachycardia in O. niloticus, determined by a reduction in cardiac parasympathetic activity and by circulating NANC factors-the first time such positive chronotropes were detected in digesting fish. Unexpectedly, postprandial ventilatory alterations were not observed, although digestion triggered mechanisms that were presumed to increase oxygen uptake, such as cardiorespiratory synchrony.
Collapse
Affiliation(s)
- Igor Noll Guagnoni
- Department of Zoology and Botany, Institute of Biosciences, Languages and Exact Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, 15054-000, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT, FAPESP/CNPq), São Paulo, Brazil
| | - Vinicius Araújo Armelin
- Department of Zoology and Botany, Institute of Biosciences, Languages and Exact Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, 15054-000, Brazil.,Department of Physiology, Institute of Biosciences, University of São Paulo (USP), Rua do Matão, Travessa 14, 321, São Paulo, SP, 05508-090, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT, FAPESP/CNPq), São Paulo, Brazil
| | - Victor Hugo da Silva Braga
- Department of Zoology and Botany, Institute of Biosciences, Languages and Exact Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, 15054-000, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT, FAPESP/CNPq), São Paulo, Brazil
| | - Francisco Tadeu Rantin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Rodovia Washington Luiz, km 235, São Carlos, SP, 13565‑905, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT, FAPESP/CNPq), São Paulo, Brazil
| | - Luiz Henrique Florindo
- Department of Zoology and Botany, Institute of Biosciences, Languages and Exact Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, 15054-000, Brazil. .,Aquaculture Center (CAUNESP), São Paulo State University (UNESP), Rodovia Prof. Paulo Donato Castellane, n/n, Jaboticabal, SP, 14884-900, Brazil. .,National Institute of Science and Technology in Comparative Physiology (INCT, FAPESP/CNPq), São Paulo, Brazil.
| |
Collapse
|
12
|
Abstract
In the 1950s, Arthur C. Guyton removed the heart from its pedestal in cardiovascular physiology by arguing that cardiac output is primarily regulated by the peripheral vasculature. This is counterintuitive, as modulating heart rate would appear to be the most obvious means of regulating cardiac output. In this Review, we visit recent and classic advances in comparative physiology in light of this concept. Although most vertebrates increase heart rate when oxygen demands rise (e.g. during activity or warming), experimental evidence suggests that this tachycardia is neither necessary nor sufficient to drive a change in cardiac output (i.e. systemic blood flow, Q̇ sys) under most circumstances. Instead, Q̇ sys is determined by the interplay between vascular conductance (resistance) and capacitance (which is mainly determined by the venous circulation), with a limited and variable contribution from heart function (myocardial inotropy). This pattern prevails across vertebrates; however, we also highlight the unique adaptations that have evolved in certain vertebrate groups to regulate venous return during diving bradycardia (i.e. inferior caval sphincters in diving mammals and atrial smooth muscle in turtles). Going forward, future investigation of cardiovascular responses to altered metabolic rate should pay equal consideration to the factors influencing venous return and cardiac filling as to the factors dictating cardiac function and heart rate.
Collapse
Affiliation(s)
- William Joyce
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark .,Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| |
Collapse
|
13
|
Duran LM, Taylor EW, Sanches PVW, Cruz AL, Tavares D, Sartori MR, Abe AS, Leite CAC. Heart rate variability in the tegu lizard, Salvator merianae, its neuroanatomical basis and role in the assessment of recovery from experimental manipulation. Comp Biochem Physiol A Mol Integr Physiol 2019; 240:110607. [PMID: 31707060 DOI: 10.1016/j.cbpa.2019.110607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 10/25/2022]
Abstract
Using long-term, remote recordings of heart rate (fH) on fully recovered, undisturbed lizards, we identified several components of heart rate variability (HRV) associated with respiratory sinus arrhythmia (RSA): 1.) A peak in the spectral representation of HRV at the frequency range of ventilation. 2.) These cardiorespiratory interactions were shown to be dependent on the parasympathetic arm of the autonomic nervous system. 3.) Vagal preganglionic neurons are located in discrete groups located in the dorsal motor nucleus of the vagus and also, in a ventro-lateral group, homologous to the nucleus ambiguus of mammals. 4.) Myelinated nerve fibers in the cardiac vagus enabling rapid communication between the central nervous system and the heart. Furthermore, the study of the progressive recovery of fH in tegu following anesthesia and instrumentation revealed that 'resting' levels of mean fH and reestablishment of HRV occurred over different time courses. Accordingly, we suggest that, when an experiment is designed to study a physiological variable reliant on autonomic modulation at its normal, resting level, then postsurgical reestablishment of HRV should be considered as the index of full recovery, rather than mean fH.
Collapse
Affiliation(s)
- Livia M Duran
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13.565-905, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - Edwin W Taylor
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13.565-905, SP, Brazil
| | - Pollyana V W Sanches
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13.565-905, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - André L Cruz
- Institute of Biology, Federal University of Bahia (UFBA), Salvador 40.140-310, BA, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - Driele Tavares
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13.565-905, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - Marina R Sartori
- Department of Zoology, São Paulo State University (UNESP), Rio Claro 13.506-900, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - Augusto S Abe
- Department of Zoology, São Paulo State University (UNESP), Rio Claro 13.506-900, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil
| | - Cleo A C Leite
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13.565-905, SP, Brazil; National Institute of Science and Technology in Comparative Physiology, INCT, FISC, FAPESP/CNPq, Rio Claro 13.506-900, SP, Brazil.
| |
Collapse
|
14
|
Leo S, Gattuso A, Mazza R, Filice M, Cerra MC, Imbrogno S. Cardiac influence of the β3-adrenoceptor in the goldfish ( Carassius auratus): a protective role under hypoxia? ACTA ACUST UNITED AC 2019; 222:jeb.211334. [PMID: 31527180 DOI: 10.1242/jeb.211334] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/11/2019] [Indexed: 12/18/2022]
Abstract
The goldfish (Carassius auratus) exhibits a remarkable capacity to survive and remain active under prolonged and severe hypoxia, making it a good model for studying cardiac function when oxygen availability is a limiting factor. Under hypoxia, the goldfish heart increases its performance, representing a putative component of hypoxia tolerance; however, the underlying mechanisms have not yet been elucidated. Here, we aimed to investigate the role of β3-adrenoreceptors (ARs) in the mechanisms that modulate goldfish heart performance along with the impact of oxygen levels. By western blotting analysis, we found that the goldfish heart expresses β3-ARs, and this expression increases under hypoxia. The effects of β3-AR stimulation were analysed by using an ex vivo working heart preparation. Under normoxia, the β3-AR-selective agonist BRL37344 (10-12 to 10-7 mol l-1) elicited a concentration-dependent increase of contractility that was abolished by a specific β3-AR antagonist (SR59230A; 10-8 mol l-1), but not by α/β1/β2-AR inhibitors (phentolamine, nadolol and ICI118,551; 10-7 mol l-1). Under acute hypoxia, BRL37344 did not affect goldfish heart performance. However, SR59230A, but not phentolamine, nadolol or ICI118,551, abolished the time-dependent enhancement of contractility that characterizes the hypoxic goldfish heart. Under both normoxia and hypoxia, adenylate cyclase and cAMP were found to be involved in the β3-AR-dependent downstream transduction pathway. In summary, we show the presence of functional β3-ARs in the goldfish heart, whose activation modulates basal performance and contributes to a hypoxia-dependent increase of contractility.
Collapse
Affiliation(s)
- Serena Leo
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Alfonsina Gattuso
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Rosa Mazza
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Mariacristina Filice
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Maria Carmela Cerra
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| | - Sandra Imbrogno
- Dept of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Arcavacata di Rende (CS), Italy
| |
Collapse
|
15
|
Cardiovascular and ventilatory interactions in the facultative air-breathing teleost Pangasianodon hypophthalmus. J Comp Physiol B 2019; 189:425-440. [DOI: 10.1007/s00360-019-01225-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/20/2019] [Accepted: 06/24/2019] [Indexed: 02/07/2023]
|
16
|
Gilbert MJH, Rani V, McKenzie SM, Farrell AP. Autonomic cardiac regulation facilitates acute heat tolerance in rainbow trout: in situ and in vivo support. ACTA ACUST UNITED AC 2019; 222:jeb.194365. [PMID: 31015284 DOI: 10.1242/jeb.194365] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/10/2019] [Indexed: 12/27/2022]
Abstract
Acute warming in fish increases heart rate (f H) and cardiac output to peak values, after which performance plateaus or declines and arrhythmia may occur. This cardiac response can place a convective limitation on systemic oxygen delivery at high temperatures. To test the hypothesis that autonomic cardiac regulation protects cardiac performance in rainbow trout during acute warming, we investigated adrenergic and cholinergic regulation during the onset and progression of cardiac limitations. We explored the direct effects of adrenergic stimulation by acutely warming an in situ working perfused heart until arrhythmia occurred, cooling the heart to restore rhythmicity and rewarming with increasing adrenergic stimulation. Adrenergic stimulation produced a clear, dose-dependent increase in the temperature and peak f H achieved prior to the onset of arrhythmia. To examine how this adrenergic protection functions in conjunction with cholinergic vagal inhibition in vivo, rainbow trout fitted with ECG electrodes were acutely warmed in a respirometer until they lost equilibrium (CTmax) with and without muscarinic (atropine) and β-adrenergic (sotalol) antagonists. Trout exhibited roughly equal and opposing cholinergic and adrenergic tone on f H that persisted up to critical temperatures. β-Adrenergic blockade significantly lowered peak f H by 14-17%, while muscarinic blockade significantly lowered the temperature for peak f H by 2.0°C. Moreover, muscarinic and β-adrenergic blockers injected individually or together significantly reduced CTmax by up to 3°C, indicating for the first time that cardiac adrenergic stimulation and cholinergic inhibition can enhance acute heat tolerance in rainbow trout at the level of the heart and the whole animal.
Collapse
Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Varsha Rani
- Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Sean M McKenzie
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.,Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| |
Collapse
|
17
|
Joyce W, Egginton S, Farrell AP, Axelsson M. Adrenergic and adenosinergic regulation of the cardiovascular system in an Antarctic icefish: Insight into central and peripheral determinants of cardiac output. Comp Biochem Physiol A Mol Integr Physiol 2019; 230:28-38. [DOI: 10.1016/j.cbpa.2018.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 01/27/2023]
|
18
|
Armelin VA, da Silva Braga VH, Guagnoni IN, Crestani AM, Abe AS, Florindo LH. Autonomic control of cardiovascular adjustments associated with orthostasis in the scansorial snake Boa constrictor. ACTA ACUST UNITED AC 2019; 222:jeb.197848. [PMID: 30760553 DOI: 10.1242/jeb.197848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/04/2019] [Indexed: 11/20/2022]
Abstract
Orthostatic hypotension is a phenomenon triggered by a change in the position or posture of an animal, from a horizontal to a vertical head-up orientation, characterised by a blood pooling in the lower body and a reduction in central and cranial arterial blood pressure (P A). This hypotension elicits systemic vasoconstriction and tachycardia, which generally reduce blood pooling and increase P A Little is known about the mediation and importance of such cardiovascular adjustments that counteract the haemodynamic effects of orthostasis in ectothermic vertebrates, and some discrepancies exist in the information available on this subject. Thus, we sought to expand our knowledge on this issue by investigating it in a more elaborate way, through an in vivo pharmacological approach considering temporal circulatory changes during head-up body inclinations in unanaesthetised Boa constrictor To do so, we analysed temporal changes in P A, heart rate (f H) and cardiac autonomic tone associated with 30 and 60 deg inclinations, before and after muscarinic blockade with atropine, double blockade with atropine and propranolol, and α1-adrenergic receptor blockade with prazosin. Additionally, the animals' f H variability was analysed. The results revealed that, in B. constrictor: (1) the orthostatic tachycardia is initially mediated by a decrease in cholinergic tone followed by an increase in adrenergic tone, a pattern that may be evolutionarily conserved in vertebrates; (2) the orthostatic tachycardia is important for avoiding an intense decrease in P A at the beginning of body inclinations; and (3) α1-adrenergic orthostatic vasomotor responses are important for the maintenance of P A at satisfactory values during long-term inclinations.
Collapse
Affiliation(s)
- Vinicius Araújo Armelin
- Department of Zoology and Botany, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil .,National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil
| | - Victor Hugo da Silva Braga
- Department of Zoology and Botany, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil
| | - Igor Noll Guagnoni
- Department of Zoology and Botany, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil
| | - Ariela Maltarolo Crestani
- Department of Zoology and Botany, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil
| | - Augusto Shinya Abe
- National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil.,Department of Zoology, São Paulo State University (UNESP), Avenida 24A, 1515, Rio Claro, SP 13506-900, Brazil.,Aquaculture Centre (CAUNESP), São Paulo State University (UNESP), Rodovia Prof. Paulo Donato Castellane, n/n, Jaboticabal, SP 14884-900, Brazil
| | - Luiz Henrique Florindo
- Department of Zoology and Botany, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, Brazil .,National Institute of Science and Technology in Comparative Physiology (INCT - FISC - FAPESP/CNPq), Rio Claro, SP 13506-900, Brazil.,Aquaculture Centre (CAUNESP), São Paulo State University (UNESP), Rodovia Prof. Paulo Donato Castellane, n/n, Jaboticabal, SP 14884-900, Brazil
| |
Collapse
|
19
|
The effects of embryonic hypoxic programming on cardiovascular function and autonomic regulation in the American alligator (Alligator mississippiensis) at rest and during swimming. J Comp Physiol B 2018; 188:967-976. [DOI: 10.1007/s00360-018-1181-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/25/2018] [Accepted: 09/06/2018] [Indexed: 02/08/2023]
|
20
|
Acharya-Patel N, Deck CA, Milsom WK. Cardiorespiratory interactions in the Pacific spiny dogfish, Squalus suckleyi. ACTA ACUST UNITED AC 2018; 221:jeb.183830. [PMID: 30012576 DOI: 10.1242/jeb.183830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/09/2018] [Indexed: 11/20/2022]
Abstract
Elasmobranchs are a group of cartilaginous fish with no direct sympathetic innervation of the heart or gills. Fast cardiorespiratory regulation is controlled solely by the parasympathetic branch of the autonomic nervous system. Cardiovascular changes associated with ventilation are commonly present in the form of respiratory sinus arrhythmia (RSA) and as cardiorespiratory synchrony (CRS, in which there is a 1:1 beat to breath ratio). The latter has been hypothesized to maximize oxygen uptake, coupling the pulsatile flows of blood and water in the gills. Given this, we hypothesized that CRS should be more prevalent in situations of low oxygen supply and RSA should be abolished by vagotomy. To test this, we investigated the role of the vagus nerve in mediating cardiorespiratory responses to changing environmental oxygen conditions in the elasmobranch Squalus suckleyi Hypoxia and hyperoxia had little effect on heart rate but did alter breathing frequency and amplitude. Atropine yielded an overall tachycardia in all oxygen conditions and abolished all heart rate variability (HRV), suggesting that HRV solely reflects fluctuating vagal tonus on the heart. Regardless of the presence of atropine, hypoxia still induced an increase in ventilation rate and depth. CRS was only found during progressive hyperoxia post-atropine, when heart rate was uninhibited and ventilation was slowed owing to the increase in oxygen supply, suggesting that in S. suckleyi, CRS is an epiphenomenon and not actively regulated to maximize gas exchange efficiency.
Collapse
Affiliation(s)
- Neha Acharya-Patel
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, Canada V6T 1Z4
| | - Courtney A Deck
- Department of Biological Sciences, North Carolina State University, Box 7617, Raleigh, NC, 27695-7617 USA
| | - William K Milsom
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, Canada V6T 1Z4
| |
Collapse
|
21
|
Troiano NM, Armelin VA, Braga VHDS, Abe AS, Rantin FT, Florindo LH. The autonomic control of upright posture tachycardia in the arboreal lizard Iguana iguana. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2018; 329:130-139. [PMID: 29992754 DOI: 10.1002/jez.2213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 11/11/2022]
Abstract
In terrestrial environments, upright spatial orientation can dramatically influence animals' hemodynamics. Generally, large and elongated species are particularly sensitive to such influence due to the greater extent of their vascular beds being verticalized, favoring the establishment of blood columns in their bodies along with caudal blood pooling, and thus jeopardizing blood circulation through a cascade effect of reductions in venous return, cardiac filling, stroke volume, cardiac output, and arterial blood pressure. This hypotension triggers an orthostatic-(baroreflex)-tachycardia to normalize arterial pressure, and despite the extensive observation of this heart rate (fH ) adjustment in experiments on orthostasis, little is known about its mediation and importance in ectothermic vertebrates. In addition, most of the knowledge on this subject comes from studies on snakes. Thus, our objective was to expand the knowledge on this issue by investigating it in an arboreal lizard (Iguana iguana). To do so, we analyzed fH , cardiac autonomic tones, and fH variability in horizontalized and tilted iguanas (0°, 30°. and 60°) before and after muscarinic blockade with atropine and double autonomic blockade with atropine and propranolol. The results revealed that I. Iguana exhibits significant orthostatic-tachycardia only at 60o inclinations-a condition that is primarily elicited by a withdrawal of vagal drive. Also, as in humans, increases in low-frequency fH oscillations and decreases in high-frequency fH oscillations were observed along with orthostatic-tachycardia, suggesting that the mediation of this fH adjustment may be evolutionarily conserved in vertebrates.
Collapse
Affiliation(s)
- Natalia Miriã Troiano
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
| | - Vinicius Araújo Armelin
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
| | - Victor Hugo da Silva Braga
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
| | - Augusto Shinya Abe
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
- Department of Zoology, São Paulo State University (UNESP), Rio Claro, Brazil
- Aquaculture Center (CAUNESP), São Paulo State University (UNESP), Jaboticabal, Brazil
| | - Francisco Tadeu Rantin
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, Brazil
| | - Luiz Henrique Florindo
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, Brazil
- Aquaculture Center (CAUNESP), São Paulo State University (UNESP), Jaboticabal, Brazil
| |
Collapse
|
22
|
The influence of midazolam on heart rate arises from cardiac autonomic tones alterations in Burmese pythons, Python molurus. Auton Neurosci 2017; 208:103-112. [PMID: 29104018 DOI: 10.1016/j.autneu.2017.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 11/22/2022]
Abstract
The GABAA receptor agonist midazolam is a compound widely used as a tranquilizer and sedative in mammals and reptiles. It is already known that this benzodiazepine produces small to intermediate heart rate (HR) alterations in mammals, however, its influence on reptiles' HR remains unexplored. Thus, the present study sought to verify the effects of midazolam on HR and cardiac modulation in the snake Python molurus. To do so, the snakes' HR, cardiac autonomic tones, and HR variability were evaluated during four different experimental stages. The first stage consisted on the data acquisition of animals under untreated conditions, in which were then administered atropine (2.5mgkg-1; intraperitoneal), followed later by propranolol (3.5mgkg-1; intraperitoneal) (cardiac double autonomic blockade). The second stage focused on the data acquisition of animals under midazolam effect (1.0mgkg-1; intramuscular), which passed through the same autonomic blockade protocol of the first stage. The third and fourth stages consisted of the same protocol of stages one and two, respectively, with the exception that atropine and propranolol injections were reversed. By comparing the HR of animals that received midazolam (second and fourth stages) with those that did not (first and third stages), it could be observed that this benzodiazepine reduced the snakes' HR by ~60%. The calculated autonomic tones showed that such cardiac depression was elicited by an ~80% decrease in cardiac adrenergic tone and an ~620% increase in cardiac cholinergic tone - a finding that was further supported by the results of HR variability analysis.
Collapse
|
23
|
Longhini LS, Zena LA, da Silva GSF, Bícego KC, Gargaglioni LH. Temperature effects on the cardiorespiratory control of American bullfrog tadpoles based on a non-invasive methodology. ACTA ACUST UNITED AC 2017; 220:3763-3770. [PMID: 28819055 DOI: 10.1242/jeb.160911] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 08/14/2017] [Indexed: 11/20/2022]
Abstract
Temperature effects on cardiac autonomic tonus in amphibian larval stages have never been investigated. Therefore, we evaluated the effect of different temperatures (15, 25 and 30°C) on the cardiorespiratory rates and cardiac autonomic tonus of premetamorphic tadpoles of the bullfrog, Lithobates catesbeianus To this end, a non-invasive method was developed to permit measurements of electrocardiogram (ECG) and buccal movements (fB; surface electromyography of the buccal floor). For evaluation of autonomic regulation, intraperitoneal injections of Ringer solution (control), atropine (cholinergic muscarinic antagonist) and sotalol (β-adrenergic antagonist) were performed. Ringer solution injections did not affect heart rate (fH) or fB across temperatures. Cardiorespiratory parameters were significantly augmented by temperature (fH: 24.5±1.0, 54.5±2.0 and 75.8±2.8 beats min-1 at 15, 25 and 30°C, respectively; fB: 30.3±1.1, 73.1±4.0 and 100.6±3.7 movements min-1 at 15, 25 and 30°C, respectively). A predominant vagal tone was observed at 15°C (32.0±3.2%) and 25°C (27.2±6.7%) relative to the adrenergic tone. At 30°C, the adrenergic tone increased relative to the lower temperature. In conclusion, the cholinergic and adrenergic tones seem to be independent of temperature for colder thermal intervals (15-25°C), while exposure to a hotter ambient temperature (30°C) seems to be followed by a significant increase in adrenergic tone and may reflect cardiovascular adjustments made to match oxygen delivery to demand. Furthermore, while excluding the use of implantable electrodes or cannulae, this study provides a suitable non-invasive method for investigating cardiorespiratory function (cardiac and respiratory rates) in water-breathing animals such as the tadpole.
Collapse
Affiliation(s)
- Leonardo S Longhini
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil
| | - Lucas A Zena
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil .,National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil
| | - Glauber S F da Silva
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil .,National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil
| |
Collapse
|
24
|
Johansen IB, Sandblom E, Skov PV, Gräns A, Ekström A, Lunde IG, Vindas MA, Zhang L, Höglund E, Frisk M, Sjaastad I, Nilsson GE, Øverli Ø. Bigger is not better: cortisol-induced cardiac growth and dysfunction in salmonids. ACTA ACUST UNITED AC 2017; 220:2545-2553. [PMID: 28476893 DOI: 10.1242/jeb.135046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/02/2017] [Indexed: 01/04/2023]
Abstract
Stress and elevated cortisol levels are associated with pathological heart growth and cardiovascular disease in humans and other mammals. We recently established a link between heritable variation in post-stress cortisol production and cardiac growth in salmonid fish too. A conserved stimulatory effect of the otherwise catabolic steroid hormone cortisol is probably implied, but has to date not been established experimentally. Furthermore, whereas cardiac growth is associated with failure of the mammalian heart, pathological cardiac hypertrophy has not previously been described in fish. Here, we show that rainbow trout (Oncorhynchus mykiss) treated with cortisol in the diet for 45 days have enlarged hearts with lower maximum stroke volume and cardiac output. In accordance with impaired cardiac performance, overall circulatory oxygen-transporting capacity was diminished as indicated by reduced aerobic swimming performance. In contrast to the well-known adaptive/physiological heart growth observed in fish, cortisol-induced growth is maladaptive. Furthermore, the observed heart growth was associated with up-regulated signature genes of mammalian cardiac pathology, suggesting that signalling pathways mediating cortisol-induced cardiac remodelling in fish are conserved from fish to mammals. Altogether, we show that excessive cortisol can induce pathological cardiac remodelling. This is the first study to report and integrate the etiology, physiology and molecular biology of cortisol-induced pathological remodelling in fish.
Collapse
Affiliation(s)
- Ida B Johansen
- Department of Biosciences, University of Oslo, Blindern, 0316 Oslo, Norway .,Bjørknes College, 0456 Oslo, Norway.,Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Peter V Skov
- National Institute of Aquatic Resources, Technical University of Denmark, North Sea Science Centre, Section for Aquaculture, 9850 Hirtshals, Denmark
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 532 23 Skara, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Ida G Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0424 Oslo, Norway.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Marco A Vindas
- Department of Biosciences, University of Oslo, Blindern, 0316 Oslo, Norway
| | - Lili Zhang
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0424 Oslo, Norway
| | - Erik Höglund
- Norwegian Institute of Water Research (NIVA), Gaustadalléen 21, 0349 Oslo, Norway.,Centre of Coastal Research, University of Agder, PO Box 422, 4604 Kristiansand, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0424 Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0424 Oslo, Norway
| | - Göran E Nilsson
- Department of Biosciences, University of Oslo, Blindern, 0316 Oslo, Norway
| | - Øyvind Øverli
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| |
Collapse
|
25
|
The role of the autonomic nervous system in control of cardiac and air-breathing responses to sustained aerobic exercise in the African sharptooth catfish Clarias gariepinus. Comp Biochem Physiol A Mol Integr Physiol 2017; 203:273-280. [DOI: 10.1016/j.cbpa.2016.09.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 01/24/2023]
|
26
|
|
27
|
Abramochkin DV, Vornanen M. Seasonal changes of cholinergic response in the atrium of Arctic navaga cod (Eleginus navaga). J Comp Physiol B 2016; 187:329-338. [PMID: 27672043 DOI: 10.1007/s00360-016-1032-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 08/26/2016] [Accepted: 09/13/2016] [Indexed: 11/24/2022]
Abstract
Fishes of north-temperate latitudes exhibit marked seasonal changes in electrical excitability of the heart partly as an outcome of temperature-dependent changes in the density of major K+ ion currents: delayed rectifiers (IKr, IKs) and background inward rectifier (IK1). In the arctic teleost, navaga cod (Eleginus navaga), IKr and IK1 are strongly up-regulated in winter. The current study tests the hypothesis that the ligand-gated K+ current, the acetylcholine-activated inward rectifier, IKACh, is also modified by seasonal acclimatization in atrial myocytes of navaga. In sinoatrial preparations of the summer-acclimatized (SA) navaga, 10-6 M carbamylcholine chloride (CCh) caused slowing of heart rate, shortening of atrial action potential (AP) duration and a drastic reduction of AP amplitude, eventually resulting in inexcitability. In winter-acclimatized (WA) atria CCh slowed HR and reduced AP duration, but reduction of AP amplitude was modest and never resulted in inexcitability. The difference in cholinergic response between SA and WA navaga is explained by seasonal changes in IKACh density. The peak density of IKACh, induced by 10-5 M CCh, at the common experimental temperature (+6 °C) was 0.97 ± 0.28 pA/pF in SA navaga but only 0.183 ± 0.013 pA/pF in WA navaga (a 5.3-fold difference, P < 0.05). At acclimatization temperatures of the fish IKACh density was 2.8 ± 0.50 (at +12 °C) and 0.11 ± 0.06 pA/pF (at +3 °C) (a 26-fold difference, P < 0.05) for SA and WA navaga, respectively. Thus, acclimatization to summer induces a drastic up-regulation of the atrial IKACh, which effectively shortens atrial AP. The reverse temperature compensation of the atrial IKACh may be advantageous in summer under variable water temperatures and oxygen concentrations by reducing workload of the heart.
Collapse
Affiliation(s)
- Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia. .,Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russia.
| | - Matti Vornanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| |
Collapse
|
28
|
Braga VHDS, Armelin VA, Teixeira MT, Abe AS, Rantin FT, Florindo LH. The Effects of Feeding on Cardiac Control of the Broad-Nosed Caiman (Caiman latirostris): The Role of the Autonomic Nervous System and NANC Factors. ACTA ACUST UNITED AC 2016; 325:524-531. [DOI: 10.1002/jez.2036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/06/2016] [Accepted: 08/05/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Victor Hugo Da Silva Braga
- Department of Zoology and Botany; São Paulo State University (UNESP); São José do Rio Preto São Paulo Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
| | - Vinicius Araújo Armelin
- Department of Zoology and Botany; São Paulo State University (UNESP); São José do Rio Preto São Paulo Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
| | - Mariana Teodoro Teixeira
- Department of Zoology and Botany; São Paulo State University (UNESP); São José do Rio Preto São Paulo Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
| | - Augusto Shinya Abe
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
- Department of Zoology; São Paulo State University (UNESP); Rio Claro São Paulo Brazil
- Aquaculture Center (CAUNESP); São Paulo State University (UNESP); Jaboticabal São Paulo Brazil
| | - Francisco Tadeu Rantin
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos, São Paulo Brazil
| | - Luiz Henrique Florindo
- Department of Zoology and Botany; São Paulo State University (UNESP); São José do Rio Preto São Paulo Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq); São Paulo Brazil
- Aquaculture Center (CAUNESP); São Paulo State University (UNESP); Jaboticabal São Paulo Brazil
| |
Collapse
|
29
|
Carravieri A, Müller MS, Yoda K, Hayama SI, Yamamoto M. Dominant Parasympathetic Modulation of Heart Rate and Heart Rate Variability in a Wild-Caught Seabird. Physiol Biochem Zool 2016; 89:263-76. [PMID: 27327178 DOI: 10.1086/686894] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Heart rate (HR) and heart rate variability (HRV) provide noninvasive measures of the relative activity of the parasympathetic nervous system (PNS), which promotes self-maintenance and restoration, and the sympathetic nervous system (SNS), which prepares an animal for danger. The PNS decreases HR, whereas the SNS increases HR. The PNS and SNS also contribute to oscillations in heartbeat intervals at different frequencies, producing HRV. HRV promotes resilience and adjustment capacity in the organism to intrinsic and extrinsic changes. Measuring HRV can reveal the condition and emotional state of animals, including aspects of their stress physiology. Until now, the functioning of the PNS and SNS and their relationship with other physiological systems have been studied almost exclusively in humans. In this study, we tested their influence on HR and HRV for the first time in a wild-caught seabird, the streaked shearwater (Calonectris leucomelas). We analyzed electrocardiograms collected from birds carrying externally attached HR loggers and that received injections that pharmacologically blocked the PNS, the SNS, or both, as well as those that received a saline (sham) injection or no injection (control). The PNS strongly dominated modulation of HR and also HRV across all frequencies, whereas the SNS contributed only slightly to low-frequency oscillations. The saline injection itself acted as a stressor, causing a dramatic drop in PNS activity in HRV and an increase in HR, though PNS activity continued to dominate even during acute stress. Dominant PNS activity is expected for long-lived species, which should employ physiological strategies that minimize somatic deterioration coming from stress.
Collapse
|
30
|
Vanegas G, Lancien F, Leprince J, Vaudry H, Le Mével JC. Effects of peripherally administered urotensin II and arginine vasotocin on the QT interval of the electrocardiogram in trout. Comp Biochem Physiol C Toxicol Pharmacol 2016; 183-184:53-60. [PMID: 26902806 DOI: 10.1016/j.cbpc.2016.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/27/2016] [Accepted: 01/27/2016] [Indexed: 11/20/2022]
Abstract
The QT interval of the electrocardiogram (ECG) is a measure of the duration of the ventricular depolarization and repolarization. In fish as in human, the QT interval is positively correlated with the RR interval of the ECG, a measure of the cardiac cycle length. Urotensin II (UII) is a neuropeptide that has been highly conserved from fish to human, and UII and its receptor (UT) are expressed in cardiovascular tissues including the heart. Although UII exerts potent cardiovascular actions, its possible effects on the QT interval have never been investigated. The goal of the present study was to provide insight into the potential effect of UII on the QT interval in an established in vivo trout model. To this end, the effects of UII on dorsal aortic blood pressure (PDA), RR, QT intervals and corrected QT (QTc) for RR interval, were investigated after intra-arterial (IA) injection of 5, 50 and 100 pmol UII. The effects of UII were compared to those of two structurally UII-related peptides (URPs), URP1 and URP2, and to those of arginine vasotocin (AVT), homolog of the mammalian arginine vasopressin. IA injection of vehicle or 5 pmol UII had no effect on the various parameters. At the 50-pmol dose, UII evoked its usual increase in PDA with a peak value observed 15 min after the injection (+22% from baseline, P<0.001). This hypertensive effect of UII was accompanied by a significant increase in the RR interval (+18%, P<0.001), i.e. a bradycardia, and these effects remained constant until the end of the recording. The highest dose of UII evoked similar hypertensive and bradycardic effects. Of interest, the QT interval did not change during the bradycardic action of UII (50 and 100 pmol) but the QTc interval significantly decreased. In trout pre-treated with urantide, a peptidic antagonist of UT, the hypertensive and bradycardic actions of 50 pmol UII were reduced 3-fold and no change occurred in the QT and QTc intervals. In trout pre-treated with blockers of the autonomic nervous system, the hypertensive effect of UII was maintained but no change appeared in RR, QT and QTc intervals. IA injections of 50 pmol URPs were without action on the preceding parameters. IA administration of 50 pmol AVT provoked quite similar increase in PDA, and elevation of the RR interval to those evoked by IA injection of UII but, in contrast to UII, AVT injection induced a highly significant and sustained prolongation of the QT interval compared to baseline (+7%, P<0.001) without change in QTc. Our results are indicative of a lack of QT interval change during UII-evoked bradycardia but not after AVT-induced bradycardia and suggest for the first time that some compensatory mechanism specific for the UII peptide is working to stabilize the QT interval. Further research is needed to elucidate the mechanism involved in this action of UII. The potential for UII to prevent detrimental prolongation of cardiac ventricular repolarization might be questioned.
Collapse
Affiliation(s)
- Gilmer Vanegas
- INSERM UMR1101, Laboratoire de Neurophysiologie, SFR ScInBioS, Université de Brest, France
| | - Frédéric Lancien
- INSERM UMR1101, Laboratoire de Neurophysiologie, SFR ScInBioS, Université de Brest, France
| | - Jérôme Leprince
- INSERM U982, UA CNRS, Différenciation et Communication Neuronale et Neuroendocrine, Université de Rouen, Mont-Saint-Aignan, France
| | - Hubert Vaudry
- INSERM U982, UA CNRS, Différenciation et Communication Neuronale et Neuroendocrine, Université de Rouen, Mont-Saint-Aignan, France
| | - Jean-Claude Le Mével
- INSERM UMR1101, Laboratoire de Neurophysiologie, SFR ScInBioS, Université de Brest, France.
| |
Collapse
|
31
|
Zena LA, Dantonio V, Gargaglioni LH, Andrade DV, Abe AS, Bícego KC. Winter metabolic depression does not change arterial baroreflex control of heart rate in the tegu lizard (Salvator merianae). J Exp Biol 2016; 219:725-33. [DOI: 10.1242/jeb.129130] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 12/17/2015] [Indexed: 11/20/2022]
Abstract
Baroreflex regulation of blood pressure (BP) is important for maintaining appropriate tissue perfusion. Although temperature affects heart rate (fH) reflex regulation in some reptiles and toads, no data are available on the influence of temperature-independent metabolic states on baroreflex. The South American tegu lizard Salvator merianae exhibits a clear seasonal cycle of activity decreasing fH along with winter metabolic downregulation, independent of body temperature. Through pharmacological interventions (phenylephrine and sodium nitroprusside), the baroreflex control of fH was studied at ∼25°C in spring-summer and winter-acclimated tegus.
In winter lizards, resting and minimum fH were lower than in spring-summer animals (respectively, 13.3±0.82 vs 10.3±0.81 and 11.2±0.65 vs 7.97±0.88 beats.min−1), while no acclimation differences occurred in resting BP (5.14±0.38 vs 5.06±0.56 kPa), baroreflex gain (94.3±10.7 vs 138.7±30.3 %.kPa−1) and rate-pressure product (an index of myocardial activity). Vagal tone exceeded the sympathetic tone of fH especially in the winter group. Therefore, despite the lower fH, winter acclimation does not diminish the fH baroreflex responses nor rate-pressure product possibly because of increased stroke volume that may arise due to heart hypertrophy. Independent of acclimation, fH responded more to hypotension than to hypertension. This should imply that tegus, which have no pressure separation within the single heart ventricle, must have other protection mechanisms against pulmonary hypertension or oedema, presumably through lymphatic drainage and/or vagal vasoconstriction of pulmonary artery. Such a predominant fH reflex response to hypothension, previously observed in anurans, crocodilians and mammals, may be a common feature of tetrapods.
Collapse
Affiliation(s)
- Lucas A. Zena
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | - Valter Dantonio
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | - Luciane H. Gargaglioni
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | - Denis V. Andrade
- Department of Zoology, Institute of Bioscience, São Paulo State University, Rio Claro, São Paulo, 13506-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | - Augusto S. Abe
- Department of Zoology, Institute of Bioscience, São Paulo State University, Rio Claro, São Paulo, 13506-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | - Kênia C. Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
- National Institute of Science and Technology – Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| |
Collapse
|
32
|
Sandblom E, Ekström A, Brijs J, Sundström LF, Jutfelt F, Clark TD, Adill A, Aho T, Gräns A. Cardiac reflexes in a warming world: Thermal plasticity of barostatic control and autonomic tones in a temperate fish. J Exp Biol 2016; 219:2880-2887. [DOI: 10.1242/jeb.140319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/04/2016] [Indexed: 12/24/2022]
Abstract
Thermal plasticity of cardiorespiratory function allows ectotherms like fish to cope with seasonal temperature changes and is critical for resilience to climate change. Yet, the chronic thermal effects on cardiovascular homeostatic reflexes in fish are little understood although this may have important implications for physiological performance and overall resilience to climate warming. We compared cardiac autonomic control and baroreflex regulation of heart rate in perch (Perca fluviatilis L.) from a reference area in the Baltic Sea at 18–19°C with conspecifics from the ‘Biotest enclosure’, a chronically heated ecosystem receiving warmed effluent water (24–25°C) from a nuclear power plant. Resting heart rates of Biotest fish displayed clear thermal compensation and were 58.3±2.3 beats min−1 compared with 52.4±2.6 beats min−1 in reference fish at their respective environmental temperatures (Q10: 1.2). The thermally-compensated heart rate of Biotest fish was a combined effect of elevated inhibitory cholinergic tone (105% in Biotest fish versus 70% in reference fish) and reduced intrinsic cardiac pacemaker rate. A barostatic response was evident in both groups, as pharmacologically-induced increases and decreases in blood pressure resulted in atropine-sensitive bradycardia and tachycardia, respectively. Yet, the tachycardia in Biotest fish was significantly greater, presumably due to the larger scope for vagal release. Acclimation of Biotest fish to 18°C for 3 weeks abolished differences in intrinsic heart rate and autonomic tones, suggesting considerable short-term thermal plasticity of cardiovascular control in this species. The heightened hypotensive tachycardia in Biotest perch may represent an important mechanism of ectothermic vertebrates that safeguards tissue perfusion pressure when tissue oxygen demand is elevated by environmental warming.
Collapse
Affiliation(s)
- E. Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - A. Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - J. Brijs
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - L. F. Sundström
- Department of Animal Ecology/Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - F. Jutfelt
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - T. D. Clark
- Australian Institute of Marine Science, Townsville, Queensland, Australia (current affiliation: University of Tasmania and CSIRO Agriculture Flagship, Hobart, Tasmania, Australia)
| | - A. Adill
- Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden
| | - T. Aho
- Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden
| | - A. Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| |
Collapse
|
33
|
Ekström A, Hellgren K, Gräns A, Pichaud N, Sandblom E. Dynamic changes in scope for heart rate and cardiac autonomic control during warm acclimation in rainbow trout. J Exp Biol 2016; 219:1106-9. [DOI: 10.1242/jeb.134312] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/04/2016] [Indexed: 11/20/2022]
Abstract
Time course studies are critical to understand regulatory mechanisms and temporal constraints in ectothermic animals acclimating to warmer temperatures. Therefore, we investigated the dynamics of heart rate and its neuro-humoral control in rainbow trout (Onchorhynchus mykiss L.) acclimating to 16°C for 39 days after being acutely warmed from 9°C. Resting heart rate was 39 bpm at 9°C, and increased significantly when acutely warmed to 16°C (Q10: 1.9), but then declined during acclimation (Q10 of 1.2 at day 39); mainly due to increased cholinergic inhibition while the intrinsic heart rate and adrenergic tone were little affected. Maximum heart rate also increased with warming, although a partial modest decrease occurred during the acclimation period. Consequently, heart rate scope exhibited a complex pattern with an initial increase with acute warming, followed by a steep decline and then a subsequent increase, which was primarily explained by cholinergic inhibition of resting heart rate.
Collapse
Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kim Hellgren
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Nicolas Pichaud
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
34
|
Sartori MR, Leite CA, Abe AS, Crossley DA, Taylor EW. The progressive onset of cholinergic and adrenergic control of heart rate during development in the green iguana, Iguana iguana. Comp Biochem Physiol A Mol Integr Physiol 2015; 188:1-8. [DOI: 10.1016/j.cbpa.2015.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 11/25/2022]
|
35
|
Teixeira MT, Armelin VA, Abe AS, Rantin FT, Florindo LH. Autonomic control of post-air-breathing tachycardia in Clarias gariepinus (Teleostei: Clariidae). J Comp Physiol B 2015; 185:669-76. [DOI: 10.1007/s00360-015-0910-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 03/27/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
|
36
|
Henriksen PS, Enok S, Overgaard J, Wang T. Food composition influences metabolism, heart rate and organ growth during digestion in Python regius. Comp Biochem Physiol A Mol Integr Physiol 2015; 183:36-44. [DOI: 10.1016/j.cbpa.2014.12.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/10/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
|
37
|
Tate KB, Kohl ZF, Eme J, Rhen T, Crossley DA. Critical Windows of Cardiovascular Susceptibility to Developmental Hypoxia in Common Snapping Turtle (Chelydra serpentina) Embryos. Physiol Biochem Zool 2015; 88:103-15. [DOI: 10.1086/677683] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
38
|
Taylor EW, Leite CAC, Sartori MR, Wang T, Abe AS, Crossley DA. The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates. ACTA ACUST UNITED AC 2014; 217:690-703. [PMID: 24574385 DOI: 10.1242/jeb.086199] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Heart rate in vertebrates is controlled by activity in the autonomic nervous system. In spontaneously active or experimentally prepared animals, inhibitory parasympathetic control is predominant and is responsible for instantaneous changes in heart rate, such as occur at the first air breath following a period of apnoea in discontinuous breathers like inactive reptiles or species that surface to air breathe after a period of submersion. Parasympathetic control, exerted via fast-conducting, myelinated efferent fibres in the vagus nerve, is also responsible for beat-to-beat changes in heart rate such as the high frequency components observed in spectral analysis of heart rate variability. These include respiratory modulation of the heartbeat that can generate cardiorespiratory synchrony in fish and respiratory sinus arrhythmia in mammals. Both may increase the effectiveness of respiratory gas exchange. Although the central interactions generating respiratory modulation of the heartbeat seem to be highly conserved through vertebrate phylogeny, they are different in kind and location, and in most species are as yet little understood. The heart in vertebrate embryos possesses both muscarinic cholinergic and β-adrenergic receptors very early in development. Adrenergic control by circulating catecholamines seems important throughout development. However, innervation of the cardiac receptors is delayed and first evidence of a functional cholinergic tonus on the heart, exerted via the vagus nerve, is often seen shortly before or immediately after hatching or birth, suggesting that it may be coordinated with the onset of central respiratory rhythmicity and subsequent breathing.
Collapse
Affiliation(s)
- Edwin W Taylor
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Campus Rio Claro, São Paulo 13506-900, Brazil
| | | | | | | | | | | |
Collapse
|
39
|
Autonomic control of heart rate during orthostasis and the importance of orthostatic-tachycardia in the snake Python molurus. J Comp Physiol B 2014; 184:903-12. [DOI: 10.1007/s00360-014-0841-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/10/2014] [Accepted: 06/20/2014] [Indexed: 10/25/2022]
|
40
|
Ekström A, Jutfelt F, Sandblom E. Effects of autonomic blockade on acute thermal tolerance and cardioventilatory performance in rainbow trout, Oncorhynchus mykiss. J Therm Biol 2014; 44:47-54. [PMID: 25086973 DOI: 10.1016/j.jtherbio.2014.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 10/25/2022]
Abstract
Predicted future increases in global temperature may impose challenges for ectothermic animals like fish, but the physiological mechanisms determining the critical thermal maximum (CTmax) are not well understood. One hypothesis suggests that impaired cardiac performance, limited by oxygen supply, is an important underlying mechanism. Since vagal bradycardia is suggested to improve cardiac oxygenation and adrenergic stimulation may improve cardiac contractility and protect cardiac function at high temperatures, we predicted that pharmacological blockade of cardiac autonomic control would lower CTmax. Rainbow trout was instrumented with a flow probe and a ventilation catheter for cardioventilatory recordings and exposed to an acute thermal challenge until CTmax following selective pharmacological blockade of muscarinic or β-adrenergic receptors. Contrary to our prediction, CTmax (~26°C) was unchanged between treatments. While β-adrenergic blockade reduced heart rate it did not impair cardiac stroke volume across temperatures suggesting that compensatory increases in cardiac filling pressure may serve to maintain cardiac output. While warming resulted in significant tachycardia and increased cardiac output, a high cholinergic tone on the heart was observed at temperatures approaching CTmax. This may represent a mechanism to maintain scope for heart rate and possibly to improve myocardial contractility and oxygen supply at high temperatures. This is the first study evaluating the importance of autonomic cardiac control on thermal tolerance in fish. While no effects on CTmax were observed, this study raises important questions about the underlying mechanisms determining thermal tolerance limits in ectothermic animals.
Collapse
Affiliation(s)
- Andreas Ekström
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg Sweden.
| | - Fredrik Jutfelt
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg Sweden; The Sven Lovén Centre for Marine Sciences, Kristineberg, Fiskebäckskil, Sweden
| | - Erik Sandblom
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg Sweden
| |
Collapse
|
41
|
Swart J, Tate K, Crossley DA. Development of adrenergic and cholinergic receptor cardiovascular regulatory capacity in the Canada goose (Branta canadensis) and domestic goose (Anser anser domesticus). Comp Biochem Physiol A Mol Integr Physiol 2014; 167:59-67. [DOI: 10.1016/j.cbpa.2013.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 11/30/2022]
|
42
|
Enok S, Simonsen LS, Wang T. The contribution of gastric digestion and ingestion of amino acids on the postprandial rise in oxygen consumption, heart rate and growth of visceral organs in pythons. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:46-53. [DOI: 10.1016/j.cbpa.2013.01.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 01/25/2013] [Accepted: 01/29/2013] [Indexed: 11/28/2022]
|
43
|
Crossley DA, Sartori MR, Abe AS, Taylor EW. A role for histamine in cardiovascular regulation in late stage embryos of the red-footed tortoise, Chelonoidis carbonaria Spix, 1824. J Comp Physiol B 2013; 183:811-20. [PMID: 23377695 DOI: 10.1007/s00360-013-0746-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 12/24/2012] [Accepted: 01/09/2013] [Indexed: 11/27/2022]
Abstract
A chorioallantoic membrane artery in embryos of the red-footed tortoise, Chelonoidis carbonaria was occlusively cannulated for measurement of blood pressure and injection of drugs. Two age groups of embryos in the final 10 % of incubation were categorized by the ratio of embryonic body to yolk mass. All embryos first received cholinergic and β-adrenergic blockade. This revealed that β-adrenergic control was established in both groups whereas cholinergic control was only established in the older group immediately prior to hatching. The study then progressed as two series. Series one was conducted in a subset of embryos treated with histamine before or after injection of ranitidine, the antagonist of H2 receptors. Injection of histamine caused an initial phasic hypertension which recovered, followed by a longer lasting hypertensive response accompanied by a tachycardia. Injection of the H2 receptor antagonist ranitidine itself caused a hypotensive tachycardia with subsequent recovery of heart rate. Ranitidine also abolished the cardiac effects of histamine injection while leaving the initial hypertensive response intact. In series, two embryos were injected with histamine after injection of diphenhydramine, the antagonist to H1 receptors. This abolished the whole of the pressor response to histamine injection but left the tachycardic response intact. These data indicate that histamine acts as a non-adrenergic, non-cholinergic factor, regulating the cardiovascular system of developing reptilian embryos and that its overall effects are mediated via both H1 and H2 receptor types.
Collapse
Affiliation(s)
- Dane A Crossley
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX 76203-5017, USA.
| | | | | | | |
Collapse
|
44
|
Petersen LH, Needham SL, Burleson ML, Overturf MD, Huggett DB. Involvement of β3-adrenergic receptors in in vivo cardiovascular regulation in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol A Mol Integr Physiol 2013; 164:291-300. [DOI: 10.1016/j.cbpa.2012.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/30/2012] [Accepted: 11/01/2012] [Indexed: 01/10/2023]
|
45
|
Slay C, Enok S, Hicks J, Wang T. Reduction of blood oxygen levels enhances postprandial cardiac hypertrophy in Burmese python (Python molurus). J Exp Biol 2013; 217:1784-9. [DOI: 10.1242/jeb.092841] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Summary
Physiological cardiac hypertrophy is characterized by reversible enlargement of cardiomyocytes and changes in chamber architecture, which increase stroke volume and VO2 max via augmented convective oxygen transport. Cardiac hypertrophy is known to occur in response to repeated elevations of O2 demand and/or reduced O2 supply in several species of vertebrate ectotherms, including postprandial Burmese pythons (Python molurus). Recent data suggest postprandial cardiac hypertrophy in P. molurus is a facultative rather than obligatory response to digestion, though the triggers of this response are unknown. Here we hypothesize that an O2 supply-demand mismatch stimulates postprandial cardiac enlargement in Burmese pythons. To test this hypothesis, we rendered animals anemic prior to feeding, essentially halving blood oxygen content during the postprandial period. Fed anemic animals had heart rates 126% higher than fasted controls, which, coupled with a 71% increase in mean arterial pressure suggests fed anemic animals were experiencing significantly elevated cardiac work. We found significant cardiac hypertrophy in fed anemic animals, which exhibited ventricles 39% larger than fasted controls and 28% larger than fed controls. These findings support our hypothesis that those animals with a greater magnitude of O2 supply-demand mismatch exhibit the largest hearts. The "low O2 signal" stimulating postprandial cardiac hypertrophy is likely mediated by elevated ventricular wall stress associated with postprandial hemodynamics.
Collapse
|
46
|
Taylor EW, Skovgaard N, Leite CA, Sartori M, de Paula GS, Abe AS. Autonomic control of heart rate is virtually independent of temperature but seems related to the neuroanatomy of the efferent vagal supply to the heart in the bullfrog, Lithobathes catesbeianus. J Therm Biol 2012. [DOI: 10.1016/j.jtherbio.2012.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
47
|
Casselman MT, Anttila K, Farrell AP. Using maximum heart rate as a rapid screening tool to determine optimum temperature for aerobic scope in Pacific salmon Oncorhynchus spp. JOURNAL OF FISH BIOLOGY 2012; 80:358-377. [PMID: 22268435 DOI: 10.1111/j.1095-8649.2011.03182.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The mean ±s.e. optimum temperature (T(opt)) for aerobic scope in juvenile coho salmon Oncorhynchus kisutch was determined to be 17·0 ± 0·7° C. The repeated measures protocol took 3 weeks to complete the T(opt) determination using 12 fish tested at five temperatures separated by 2° C increments. This experiment also demonstrated that the T(opt) was associated with maximum heart rate (f(H)) failing to maintain a Q(10) -related increase with temperature. When maximum f(H) was produced in anaesthetized fish with pharmacological stimulation and f(H) measured from electrocardiogram recordings during acute warming, the Arrhenius break temperature (ABT) for Q(10) discontinuities in maximum f(H) (mean ±s.e. = 17·1 ± 0·5° C for 15 ppm clove oil and 16·5 ± 0·2° C for 50 ppm MS-222) was statistically indistinguishable from the T(opt) measured using aerobic scope. Such a determination took only 3 days rather than 3 weeks. Therefore, it is proposed that determining ABT for discontinuities in maximum f(H) in anaesthetized fish presents itself as a valuable, high-throughput screening tool to assess T(opt) in fishes, a metric that has become recognized as being extremely valuable in fish biology and fisheries management.
Collapse
Affiliation(s)
- M T Casselman
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada.
| | | | | |
Collapse
|
48
|
Lurman GJ, Petersen LH, Gamperl AK. Atlantic cod (Gadus morhua L.) in situ cardiac performance at cold temperatures: long-term acclimation, acute thermal challenge and the role of adrenaline. J Exp Biol 2012; 215:4006-14. [DOI: 10.1242/jeb.069849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
The resting and maximum in situ cardiac performance of Newfoundland Atlantic cod (Gadus morhua L.) acclimated to 10, 4 and 0°C were measured at their respective acclimation temperatures, and when acutely exposed to temperature changes: i.e. hearts from 10°C fish cooled to 4°C, and hearts from 4°C fish measured at 10°C and 0°C. Intrinsic heart rate (fH) decreased from 41 beats min-1 (bpm) at 10°C to 33 bpm at 4°C and to 25 bpm at 0°C. However, this degree of thermal dependency was not reflected in maximal cardiac output. Qmax values were ~44, ~37 and ~34 ml min-1 kg-1 at 10, 4 and 0°C, respectively. Further, cardiac scope showed a slight positive compensation between 4 and 0°C (Q10 = 1.7), and full, if not a slight over compensation between 10 and 4°C (Q10 = 0.9). The maximal performance of hearts exposed to an acute decrease in temperature (i.e. from 10°C to 4°C and 4°C to 0°C) was comparable to that measured for hearts from 4 and 0°C acclimated fish, respectively. In contrast, 4°C acclimated hearts significantly out-performed 10°C acclimated hearts when tested at a common temperature of 10°C (in terms of both Qmax and power output). Only minimal differences in cardiac function were seen between hearts stimulated with basal (5 nM) vs. maximal (200 nM) levels of adrenaline, the effects of which were not temperature dependant. These results: 1) show that maximum performance of the isolated cod heart is not compromised by exposure to cold temperatures; and 2) support data from other studies which show that, in contrast to salmonids, cod cardiac performance/myocardial contractility is not dependent upon humoral adrenergic stimulation.
Collapse
|
49
|
Autonomic control of circulation in fish: A comparative view. Auton Neurosci 2011; 165:127-39. [DOI: 10.1016/j.autneu.2011.08.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 08/10/2011] [Accepted: 08/11/2011] [Indexed: 11/20/2022]
|
50
|
Miller SC, Gillis TE, Wright PA. The ontogeny of regulatory control of the rainbow trout (Oncorhynchus mykiss) heart and how this is influenced by chronic hypoxia exposure. J Exp Biol 2011; 214:2065-72. [DOI: 10.1242/jeb.054825] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Salmonid embryos develop in cool waters over relatively long periods of time. Interestingly, hypoxic conditions have been found to be relatively common in some nesting sites (redds). The goals of this study were to determine the ontogeny of cardiac regulation in rainbow trout early life stages and how this is influenced by chronic hypoxia. The heart rate response to cholinergic and adrenergic receptor stimulation or inhibition was measured in individuals reared in normoxic (100% O2 saturation) or hypoxic (30% O2 saturation) conditions from fertilization to embryonic stages 22, 26 and 29, and larval stages 30 and 32. In normoxia, heart rate increased in response to β-adrenergic receptor stimulation (isoproterenol) as early as embryonic stage 22, and decreased with the antagonist propranolol after this stage. Cholinergic stimulation (acetylcholine) was ineffective at all stages, but atropine (acetylcholine antagonist) increased heart rate at larval stage 32. This demonstrates that cardiac β-adrenergic receptors are functional at early life stages, while cholinergic receptors are not responsive until after hatching. Collectively, embryos had cardio-acceleration control mechanisms in place just after the heartbeat stage, while cardio-inhibitory control was not functional until after hatching. Chronic hypoxia exposure triggered bradycardia, increased the response to adrenergic stimulation in embryos and larvae, and delayed the onset of cholinergic control in larvae. In non-motile stages, therefore, survival in chronic low oxygen may depend on the ability to alter the cardiac ontogenic program to meet the physiological requirements of the developing fish.
Collapse
Affiliation(s)
- Silvana C. Miller
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Todd E. Gillis
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Patricia A. Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| |
Collapse
|