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Longhini LS, Zena LA, Polymeropoulos ET, Rocha ACG, da Silva Leandro G, Prado CPA, Bícego KC, Gargaglioni LH. Thermal Acclimation to the Highest Natural Ambient Temperature Compromises Physiological Performance in Tadpoles of a Stream-Breeding Savanna Tree Frog. Front Physiol 2021; 12:726440. [PMID: 34690802 PMCID: PMC8531205 DOI: 10.3389/fphys.2021.726440] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Amphibians may be more vulnerable to climate-driven habitat modification because of their complex life cycle dependence on land and water. Considering the current rate of global warming, it is critical to identify the vulnerability of a species by assessing its potential to acclimate to warming temperatures. In many species, thermal acclimation provides a reversible physiological adjustment in response to temperature changes, conferring resilience in a changing climate. Here, we investigate the effects of temperature acclimation on the physiological performance of tadpoles of a stream-breeding savanna tree frog (Bokermannohyla ibitiguara) in relation to the thermal conditions naturally experienced in their microhabitat (range: 18.8-24.6°C). We quantified performance measures such as routine and maximum metabolic rate at different test (15, 20, 25, 30, and 34°C) and acclimation temperatures (18 and 25°C). We also measured heart rate before and after autonomic blockade with atropine and sotalol at the respective acclimation temperatures. Further, we determined the critical thermal maximum and warming tolerance (critical thermal maximum minus maximum microhabitat temperature), which were not affected by acclimation. Mass-specific routine and mass-specific maximum metabolic rate, as well as heart rate, increased with increasing test temperatures; however, acclimation elevated mass-specific routine metabolic rate while not affecting mass-specific maximum metabolic rate. Heart rate before and after the pharmacological blockade was also unaffected by acclimation. Aerobic scope in animals acclimated to 25°C was substantially reduced, suggesting that physiological performance at the highest temperatures experienced in their natural habitat is compromised. In conclusion, the data suggest that the tadpoles of B. ibitiguara, living in a thermally stable environment, have a limited capacity to physiologically adjust to the highest temperatures found in their micro-habitat, making the species more vulnerable to future climate change.
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Affiliation(s)
- Leonardo S. Longhini
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
| | - Lucas A. Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | | | - Aline C. G. Rocha
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
| | - Gabriela da Silva Leandro
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
| | - Cynthia P. A. Prado
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
| | - Kênia C. Bícego
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
| | - Luciane H. Gargaglioni
- Departamento de Morfologia e Fisiologia Animal, Universidade Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, Brazil
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Zena LA, Leite CAC, Longhini LS, Dias DPM, da Silva GSF, Hartzler LK, Gargaglioni LH, Bícego KC. Analysis of the respiratory component of heart rate variability in the Cururu toad Rhinella schneideri. Sci Rep 2017; 7:16119. [PMID: 29170531 PMCID: PMC5701079 DOI: 10.1038/s41598-017-16350-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
Beat-to-beat variation in heart rate (f H ) has been used as a tool for elucidating the balance between sympathetic and parasympathetic modulation of the heart. A portion of the temporal changes in f H is evidenced by a respiratory influence (cardiorespiratory interaction) on heart rate variability (HRV) with heartbeats increasing and decreasing within a respiratory cycle. Nevertheless, little is known about respiratory effects on HRV in lower vertebrates. By using frequency domain analysis, we provide the first evidence of a ventilatory component in HRV similar to mammalian respiratory sinus arrhythmia in an amphibian, the toad Rhinella schneideri. Increases in the heartbeats arose synchronously with each lung inflation cycle, an intermittent breathing pattern comprised of a series of successive lung inflations. A well-marked peak in the HRV signal matching lung inflation cycle was verified in toads whenever lung inflation cycles exhibit a regular rhythm. The cardiac beat-to-beat variation evoked at the moment of lung inflation accounts for both vagal and sympathetic influences. This cardiorespiratory interaction may arise from interactions between central and peripheral feedback mechanisms governing cardiorespiratory control and may underlie important cardiorespiratory adjustments for gas exchange improvement especially under extreme conditions like low oxygen availability.
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Affiliation(s)
- Lucas A Zena
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, SP, Brazil.
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil.
| | - Cléo A C Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil
| | - Leonardo S Longhini
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, SP, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil
| | - Daniel P M Dias
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, 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, SP, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil
| | - Lynn K Hartzler
- Department of Biological Sciences, Wright State University, Dayton, OH, USA
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, SP, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, SP, Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, SP, Brazil
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