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Neto AVGS, Filogonio R, Leite CAC. Recovery of the baroreflex and autonomic modulation after anesthesia with MS-222 in bullfrogs. Comp Biochem Physiol A Mol Integr Physiol 2024; 295:111654. [PMID: 38729257 DOI: 10.1016/j.cbpa.2024.111654] [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: 03/15/2024] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024]
Abstract
The time course for recovery after anesthesia is poorly described for tricaine methanesulfonate (MS-222). We suggest that the baroreflex and the heart rate variability (HRV) could be used to index the recovery of the autonomic modulation after anesthesia. We analyzed the recovery profile of behavioral and physiological parameters over time to analyze the progression of recovery after anesthesia of American bullfrogs with MS-222. Mean heart rate stabilized after 17 h, whereas the baroreflex efficiency index took 23 h and the baroreflex operating gain, 29 h. Mean arterial pressure recovered after 26 h. Power spectral density peaked at 23 h and again after 40 h. Baroreflex was a relevant component of the first phase of HRV, while autonomic modulation for resting may take longer than 40 h. We suggest that physiological recovery is a complex phenomenon with multiple progressive phases, and the baroreflex may be a useful tool to observe the first substantial recovery of post-instrumentation capacity for autonomic modulation.
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Affiliation(s)
- Antônio V G S Neto
- Department of Physiological Sciences, Federal University of São Carlos, SP, Brazil
| | - Renato Filogonio
- Department of Physiological Sciences, Federal University of São Carlos, SP, Brazil
| | - Cléo A C Leite
- Department of Physiological Sciences, Federal University of São Carlos, SP, Brazil.
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Bagnall-Hare H, McLoone VI, Ringwood JV. On the accuracy of sequence methods for baroreflex sensitivity estimation. Phys Eng Sci Med 2024; 47:503-516. [PMID: 38564152 PMCID: PMC11166763 DOI: 10.1007/s13246-023-01380-y] [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: 03/27/2023] [Accepted: 12/22/2023] [Indexed: 04/04/2024]
Abstract
In the absence of a true gold standard for non-invasive baroreflex sensitivity estimation, it is difficult to quantify the accuracy of the variety of techniques used. A popular family of methods, usually entitled 'sequence methods' involves the extraction of (apparently) correlated sequences from blood pressure and RR-interval data and the subsequent fitting of a regression line to the data. This paper discusses the accuracy of sequence methods from a system identification perspective, using both data generated from a known mathematical model and spontaneous baroreflex data. It is shown that sequence methods can introduce significant bias in the baroreflex sensitivity estimate, even when great care is taken in sequence selection.
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Affiliation(s)
- Hasana Bagnall-Hare
- Department of Electronic Engineering, Maynooth University, Maynooth, Co. Kildare, Ireland.
| | - Violeta I McLoone
- Department of Aero, Mechanical and Electronic Engineering, South East Technological University, Waterford, Co. Carlow, Ireland
| | - John V Ringwood
- Department of Electronic Engineering, Maynooth University, Maynooth, Co. Kildare, Ireland
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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.
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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
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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.
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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
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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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Baroreflex responses to activity at different temperatures in the South American rattlesnake, Crotalus durissus. J Comp Physiol B 2021; 191:917-925. [PMID: 34363512 DOI: 10.1007/s00360-021-01396-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/15/2021] [Accepted: 07/30/2021] [Indexed: 10/20/2022]
Abstract
In humans, physical exercise imposes narrower limits for the heart rate (fH) response of the baroreflex, and vascular modulation becomes largely responsible for arterial pressure regulation. In undisturbed reptiles, the baroreflex-related fH alterations at the operating point (Gop) decreases at elevated body temperatures (Tb) and the vascular regulation changes accordingly. We investigated how the baroreflex of rattlesnakes, Crotalus durissus, is regulated during an activity at different Tb, expecting that activity would reduce the capacity of the cardiac baroreflex neural pathway to buffer arterial pressure fluctuations while being compensated by the vascular neural pathway regulation. Snakes were catheterized for blood pressure assessment at three different Tb: 15, 20 and 30 °C. Data were collected before and after activity at each Tb. Baroreflex gain (Gop) was assessed with the sequence method; the vascular limb, with the time constant of pressure decay (τ), using the two-element Windkessel equation. Both Gop and τ reduced when Tb increased. Activity also reduced Gop and τ in all Tb. The relationship between τ and pulse interval (τ/PI) was unaffected by the temperature at resting snakes, albeit it reduced after activity at 20 °C and 30 °C. The unchanged τ/PI and normalized Gop at different Tb indicated those variables are actively adjusted to work at different fH and pressure conditions at rest. Our data suggest that during activity, the baroreflex-related fH response is attenuated and hypertension is buffered by a disproportional increase in the rate which pressure decays during diastole. This compensation seems especially important at higher Tb where Gop is already low.
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