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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.
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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
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Tavares D, da Silva Matos SLB, Duran LM, Castro SA, Taylor EW, Filogonio R, Fernandes MN, Leite CA. Baroreflex responses of decerebrate rattlesnakes (Crotalus durissus) are comparable to awake animals. Comp Biochem Physiol A Mol Integr Physiol 2022; 273:111286. [DOI: 10.1016/j.cbpa.2022.111286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/29/2022] [Accepted: 08/02/2022] [Indexed: 11/30/2022]
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Rocha GC, Castro SA, Taylor EW, Tavares D, Leite CAC. A Decerebrate Preparation of the Rattlesnake, Crotalus durissus, Provides an Experimental Model for Study of Autonomic Modulation of the Cardiovascular System in Reptiles. Physiol Biochem Zool 2021; 94:269-285. [PMID: 34142933 DOI: 10.1086/714973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractThe South American rattlesnake, Crotalus durissus, has been successfully used as an experimental model to study control of the cardiovascular system in squamate reptiles. Recent technical advances, including equipment miniaturization, have lessened the impact of instrumentation on in vivo recordings, and an increased range of anesthetic drugs has improved recording conditions for in situ preparations. Nevertheless, any animal-based experimental approach has to manage limitations regarding the avoidance of pain and stress the stability of the preparation and duration of experiments and the potentially overriding effects of anesthesia. To address such aspects, we tested a new experimental preparation, the decerebrate rattlesnake, in a study of the autonomic control of cardiovascular responses following the removal of general anesthesia. The preparation exhibited complex cardiovascular adjustments to deal with acute increases in venous return (caused by tail lifting), to compensate for blood flow reduction in the cephalic region (caused by head lifting), for body temperature control (triggered by an external heating source), and in response to stimulation of chemoreceptors (triggered by intravenous injection of NaCN). The decerebrate preparation retained extensive functional integrity of autonomic centers, and it was suitable for monitoring diverse cardiac and vascular variables. Furthermore, reanesthetizing the preparation markedly blunted cardiovascular performance. Isoflurane limited the maintenance of recovered cardiovascular variables in the prepared animal and reduced or abolished the observed cardiovascular reflexes. This preparation enables the recording of multiple concomitant cardiovascular variables for the study of mechanistic questions regarding the central integration of autonomic reflex responses in the absence of anesthesia.
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Armelin VA, Braga VHDS, Teixeira MT, Guagnoni IN, Wang T, Florindo LH. The baroreflex in aquatic and amphibious teleosts: Does terrestriality represent a significant driving force for the evolution of a more effective baroreflex in vertebrates? Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110916. [PMID: 33545361 DOI: 10.1016/j.cbpa.2021.110916] [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: 09/26/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 10/22/2022]
Abstract
All vertebrates have baroreflexes that provide fast regulation of arterial blood pressure (PA) to maintain adequate tissue perfusion and avoid vascular lesions from excessive pressures. The baroreflex is a negative feedback loop, where altered PA results in reciprocal changes in heart rate (fH) and systemic vascular conductance to restore pressure. In terrestrial environments, gravity usually leads to blood pooling in the lower body reducing venous return, cardiac filling, cardiac output and PA. Conversely, in aquatic environments, the hydrostatic pressure of surrounding water mitigates blood pooling and prevents vascular distensions. In this context, we aimed to test the hypothesis that vertebrate species that were exposed to gravity-induced hemodynamic disturbances throughout their evolutionary histories have a more effective barostatic reflex than those that were not. We examined the cardiac baroreflex of fish that perform (Clarias gariepinus and Hoplerythrinus unitaeniatus) and do not perform (Hoplias malabaricus and Oreochromis niloticus) voluntary terrestrial sojourns, using pharmacological manipulations of PA to characterize reflex changes in fH using a four-variable sigmoidal logistic function (i.e. the "Oxford technique"). Our results revealed that amphibious fish exhibit higher baroreflex gain and responsiveness to hypotension than strictly aquatic fish, suggesting that terrestriality and the gravitational circulatory stresses constitute a relevant driving force for the evolution of a more effective baroreflex in vertebrates. We also demonstrate that strictly aquatic teleosts have considerable baroreflex gain, supporting the view that the baroreflex is an ancient cardiovascular trait that appeared before vertebrates colonized the gravity-dominated realm of land.
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Affiliation(s)
- Vinicius Araújo Armelin
- Department of Physiology, Institute of Biosciences, University of São Paulo (USP), Rua do Matão, Travessa 14, 321, São Paulo, SP, 05508-090, Brazil; 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 - FAPESP/CNPq), São Paulo, 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 - FAPESP/CNPq), São Paulo, Brazil
| | - Mariana Teodoro Teixeira
- 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 - FAPESP/CNPq), São Paulo, 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 - FAPESP/CNPq), São Paulo, Brazil
| | - Tobias Wang
- Section for Zoophysiology, Department of Bioscience, Aarhus University (AU), C. F. Møllers Allé 3, Aarhus, 8000 Aarhus C, Denmark; National Institute of Science and Technology in Comparative Physiology (INCT - FAPESP/CNPq), São Paulo, 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; 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
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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.
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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.
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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.
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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
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Kodirov SA, Psyrakis D, Brachmann J, Zhuravlev VL. Limulus and heart rhythm. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 331:61-79. [PMID: 30251467 DOI: 10.1002/jez.2235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 01/08/2023]
Abstract
Great interest in the comparative physiology of hearts and their functions in Animalia has emerged with classic papers on Limulus polyphemus and mollusks. The recurrent cardiac activity-heart rate-is the most important physiological parameter and when present the kardia (Greek) is vital to the development of entire organs of the organisms in the animal kingdom. Extensive studies devoted to the regulation of cardiac rhythm in invertebrates have revealed that the basics of heart physiology are comparable to mammals. The hearts of invertebrates also beat spontaneously and are supplied with regulatory nerves: either excitatory or inhibitory or both. The distinct nerves and the source of excitation/inhibition at the level of single neurons are described for many invertebrate genera. The vertebrates and a majority of invertebrates have myogenic hearts, whereas the horseshoe crab L. polyphemus and a few other animals have a neurogenic cardiac rhythm. Nevertheless, the myogenic nature of heartbeat is precursor, because the contraction of native and stem-cell-derived cardiomyocytes does occur in the absence of any neural elements. Even in L. polyphemus, the heart rhythm is myogenic at embryonic stages.
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Affiliation(s)
- Sodikdjon A Kodirov
- Department of General Physiology, Saint Petersburg University, Saint Petersburg, Russia.,Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia.,Department of Molecular Biology and Genetics, Almazov Federal Heart, Blood and Endocrinology Centre, Saint Petersburg, Russia.,Laboratory of Emotions' Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.,Department of Cardiology, University Hospital, Heidelberg, Germany
| | - Dimitrios Psyrakis
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany
| | - Johannes Brachmann
- Department of Cardiology, Klinikum Coburg, Teaching Hospital of the University of Würzburg, Coburg, Germany.,Department of Cardiology, University Hospital, Heidelberg, Germany
| | - Vladimir L Zhuravlev
- Department of General Physiology, Saint Petersburg University, Saint Petersburg, Russia.,Department of Cardiology, University Hospital, Heidelberg, Germany
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