1
|
Braga VHDS, Armelin VA, Noll IG, Florindo LH, Milsom WK. Cardiorespiratory reflexes in white sturgeon (Acipenser transmontanus): Lack of cardiac baroreflex response to blood pressure manipulation? Comp Biochem Physiol A Mol Integr Physiol 2024; 288:111554. [PMID: 37989399 DOI: 10.1016/j.cbpa.2023.111554] [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: 07/31/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 11/23/2023]
Abstract
Arterial pressure (Pa) regulation is essential to adequately distribute nutrients to metabolizing tissues, remove wastes and avoid lesions associated with hypertension. In vertebrates, short-term Pa regulation is achieved through the baroreflex, which elicits inversely proportional changes in heart rate (fH) and vascular resistance to restore Pa. The cardiac limb of this reflex has been reported in all vertebrate groups studied to date: teleosts, amphibians, snakes, lizards, crocodiles, birds and mammals - which led to the suggestion that the baroreflex is an ancient trait present in all vertebrate species. However, it is not clear whether more basal groups of vertebrates, such as cyclostomes, elasmobranchs and chondrosteans, manifest baroreflex regulation of fH. Thus, the aim of this study was to determine whether the white sturgeon (Acipenser transmontanus; Chondrostei: Acipenseridae) exhibits a cardiac baroreflex. To do so, we induced Pa perturbations through injections of phenylephrine, sodium nitroprusside (SNP) and saline solution (hypervolemia), and examined possible fH baroreflex responses. We also investigated whether fH responses triggered by fright and chemoreflex were present in this species, in order to confirm the potential of sturgeon to perform reflexive cardiac adjustments. The findings indicate that A. transmontanus exhibits reflex bradycardia in response to fright and chemoreceptor stimulation, illustrating its capacity for short-term cardiac regulation. However, this species does not display baroreflex control of fH across its physiological range. This dissociation suggests that while the nervous and cardiovascular systems of A. transmontanus are primed for rapid reflex responses, a cardiac baroreflex mechanism remains absent.
Collapse
Affiliation(s)
- 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. https://twitter.com/b07855682
| | - Vinicius Araújo Armelin
- Department of Physiology, University of São Paulo (USP), Rua do Matão - Travessa 14 - N. 101, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Igor Guagnoni Noll
- Department of Biological Sciences, São Paulo State University (UNESP), Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP 15054-000, 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; Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Rodovia Washington Luiz, km 235, São Carlos, SP 13565-905, Brazil; Aquaculture Centre (CAUNESP), São Paulo State University (UNESP), Rodovia Prof. Paulo Donato Castellane, n/n, Jaboticabal, SP 14884-900, Brazil.
| | - William Kenneth Milsom
- Department of Zoology, University of British Columbia (UBC), 4200 - 6270 University Blvd, V6T 1Z4 Vancouver, Canada
| |
Collapse
|
2
|
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]
|
3
|
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.
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Armelin VA, Braga VHDS, Teixeira MT, Guagnoni IN, Wang T, Florindo LH. The nonpharmacological sequence method provides a reliable evaluation of baroreflex sensitivity in fish. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:348-358. [PMID: 33503334 DOI: 10.1002/jez.2448] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/22/2020] [Accepted: 01/08/2021] [Indexed: 11/10/2022]
Abstract
The most commonly used technique to study the barostatic regulation of blood pressure in ectothermic vertebrates consists of determining the heart rate response to pharmacological manipulations of blood pressure, the so-called "Oxford method." Although well established, the Oxford method has some important limitations, such as induction of hypervolemia in small animals and undesired effects of vasoactive drugs on central and peripheral baroreflex components. As an alternative, the sequence method, which consists in the computerized evaluation of naturally-occurring baroreflex adjustments of heart rate without the need for pharmacological administrations, was developed to study baroreflexes. In the present study, we compare this sequence method with the Oxford technique in two teleost species with different life styles, and we assess the optimal software configuration for the employment of the sequence method in fish. Calculation of baroreflex gain through the sequence method was adequate and reliable when the software was configured to search for baroreflex sequences with a minimum length of three cardiac cycles with a delay of one cardiac cycle between fluctuations in mean ventral aortic blood pressure and reflex changes in pulse interval. When properly configured, the sequence and the Oxford methods yielded similar determinations of the baroreflex gain in fish.
Collapse
Affiliation(s)
- Vinicius A Armelin
- Department of Physiology, University of São Paulo (USP), São Paulo, SP, Brazil.,Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil
| | - Victor H da Silva Braga
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil
| | - Mariana T Teixeira
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil
| | - Igor N Guagnoni
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil
| | - Tobias Wang
- National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil.,Section for Zoophysiology, Department of Bioscience, Aarhus University (AU), Aarhus, Denmark
| | - Luiz H Florindo
- Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.,National Institute of Science and Technology in Comparative Physiology (INCT-FAPESP/CNPq), Rio Claro, SP, Brazil.,Aquaculture Center (CAUNESP), São Paulo State University (UNESP), Jaboticabal, SP, Brazil
| |
Collapse
|
6
|
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
|
7
|
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
|
8
|
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
|
9
|
Affiliation(s)
- James E. Bogan
- The Critter Fixer of Central Florida, LLC, 83 Geneva Drive, 621679, Oviedo, FL 32765, USA
| |
Collapse
|
10
|
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
|
11
|
Armelin VA, Braga VHDS, Teixeira MT, Rantin FT, Florindo LH, Kalinin AL. Gill denervation eliminates the barostatic reflex in a neotropical teleost, the tambaqui (Colossoma macropomum). FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:1213-1224. [PMID: 26932845 DOI: 10.1007/s10695-016-0211-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 02/18/2016] [Indexed: 06/05/2023]
Abstract
The baroreflex is one of the most important regulators of cardiovascular homeostasis in vertebrates. It begins with the monitoring of arterial pressure by baroreceptors, which constantly provide the central nervous system with afferent information about the status of this variable. Any change in arterial pressure relative to its normal state triggers autonomic responses, which are characterized by an inversely proportional change in heart rate and systemic vascular resistance and which tend to restore pressure normality. Although the baroreceptors have been located in mammals and other terrestrial vertebrates, their location in fish is still not completely clear and remains quite controversial. Thus, the objective of this study was to locate the baroreceptors in a teleost, the Colossoma macropomum. To do so, the occurrence and efficiency of the baroreflex were both analyzed when this mechanism was induced by pressure imbalancements in intact fish (IN), first-gill-denervated fish (G1), and total-gill-denervated fish (G4). The pressure imbalances were initiated through the administration of the α1-adrenergic agonist phenylephrine (100 µg kg(-1)) and the α1-adrenergic antagonist prazosin (1 mg kg(-1)). The baroreflex responses were then analyzed using an electrocardiogram that allowed for the measurement of the heart rate, the relationship between pre- and post-pharmacological manipulation heart rates, the time required for maximum chronotropic baroreflex response, and total heart rate variability. The results revealed that the barostatic reflex was attenuated in the G1 group and nonexistent in G4 group, findings which indicate that baroreceptors are exclusively located in the gill arches of C. macropomum.
Collapse
Affiliation(s)
- Vinicius Araújo Armelin
- 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
| | - 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
| | - 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, 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.
- Aquaculture Center (CAUNESP), São Paulo State University (UNESP), Rodovia Prof. Paulo Donato Castellane, n/n, Jaboticabal, SP, 14884-900, Brazil.
| | - Ana Lúcia Kalinin
- 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
| |
Collapse
|
12
|
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]
|