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OOTAWA T, WU S, SEKIO R, SMITH H, ISLAM MZ, NGUYEN HTT, UNO Y, SHIRAISHI M, MIYAMOTO A. Habu snakes (Protobothrops flavoviridis) show variation in thoracic aortic vasoreactivity between adjacent Japanese islands. J Vet Med Sci 2024; 86:202-206. [PMID: 38104972 PMCID: PMC10898993 DOI: 10.1292/jvms.23-0361] [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: 08/24/2023] [Accepted: 11/27/2023] [Indexed: 12/19/2023] Open
Abstract
Habu snakes (Protobothrops flavoviridis) are pit vipers found in the geographically adjacent but ecologically divergent islands of Tokunoshima and Amami-Oshima in southwestern Japan. Abiotic factors can cause variation in animal populations between the two islands, and Habu snakes may show such intraspecific physiological variation. We therefore evaluated the vasoreactivity in aortas isolated from the Habu of both islands. Tokunoshima Habu showed significantly greater contractile responses to angiotensin (Ang) II, acetylcholine (ACh) and noradrenaline, and significantly higher affinities (pEC50) for Ang II and ACh, than Amami-Oshima Habu. ACh caused contractions in aortas from both populations, a finding previously unreported in snakes. Our findings indicate that vasoreactivity may differ between Tokunoshima and Amami-Oshima Habu.
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Affiliation(s)
- Tomoki OOTAWA
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- Japan Wildlife Research Center, Tokyo, Japan
| | - Siyuan WU
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Ryoya SEKIO
- Department of Veterinary Pharmacology, Joint Faculty of
Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Henry SMITH
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Md Zahorul ISLAM
- Department of Pharmacology, Faculty of Veterinary Science,
Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Ha Thi Thanh NGUYEN
- Department of Veterinary Pharmacology and Toxicology,
Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi,
Vietnam
| | - Yasuhiro UNO
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- Department of Veterinary Pharmacology, Joint Faculty of
Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Mitsuya SHIRAISHI
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Atsushi MIYAMOTO
- Department of Basic Veterinary Science, Joint Graduate
School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- Department of Veterinary Pharmacology, Joint Faculty of
Veterinary Medicine, Kagoshima University, Kagoshima, Japan
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An overview of the phylogeny of cardiorespiratory control in vertebrates with some reflections on the 'Polyvagal Theory'. Biol Psychol 2022; 172:108382. [PMID: 35777519 DOI: 10.1016/j.biopsycho.2022.108382] [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: 03/14/2022] [Revised: 06/05/2022] [Accepted: 06/15/2022] [Indexed: 02/05/2023]
Abstract
Mammals show clear changes in heart rate linked to lung ventilation, characterized as respiratory sinus arrhythmia (RSA). These changes are controlled in part by variations in the level of inhibitory control exerted on the heart by the parasympathetic arm of the autonomic nervous system (PNS). This originates from preganglionic neurons in the nucleus ambiguous that supply phasic, respiration-related activity to the cardiac branch of the vagus nerve, via myelinated, efferent fibres with rapid conduction velocities. An elaboration of these central mechanisms, under the control of a 'vagal system' has been endowed by psychologists with multiple functions concerned with 'social engagement' in mammals and, in particular, humans. Long-term study of cardiorespiratory interactions (CRI) in other major groups of vertebrates has established that they all show both tonic and phasic control of heart rate, imposed by the PNS. This derives centrally from neurones located in variously distributed nuclei, supplying the heart via fast-conducting, myelinated, efferent fibres. Water-breathing vertebrates, which include fishes and larval amphibians, typically show direct, 1:1 CRI between heart beats and gill ventilation, controlled from the dorsal vagal motor nucleus. In air-breathing, ectothermic vertebrates, including reptiles, amphibians and lungfish, CRI mirroring RSA have been shown to improve oxygen uptake during phasic ventilation by changes in perfusion of their respiratory organs, due to shunting of blood over across their undivided hearts. This system may constitute the evolutionary basis of that generating RSA in mammals, which now lacks a major physiological role in respiratory gas exchange, due to their completely divided systemic and pulmonary circulations.
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Castro SA, Taylor ET, Tavares D, Filogonio R, Rodriges GJ, Leite CAC. Role of nitric oxide in the cardiovascular system of South American rattlesnakes (Crotalus durissus). Physiol Biochem Zool 2021; 95:168-182. [DOI: 10.1086/718292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Prenatal hypoxia affects scaling of blood pressure and arterial wall mechanics in the common snapping turtle, Chelydra serpentina. Comp Biochem Physiol A Mol Integr Physiol 2021; 260:111023. [PMID: 34224856 DOI: 10.1016/j.cbpa.2021.111023] [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: 03/09/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 11/24/2022]
Abstract
In reptiles, exposure to hypoxia during embryonic development affects several cardiovascular parameters. These modifications may impose different mechanical stress to the arterial system, and we speculated that the arterial wall of major outflow vessels would be modified accordingly. Since non-crocodilian reptiles possess a partially divided ventricle, ensuing similar systemic and pulmonary systolic pressures, we investigated how morphological and mechanical properties of segments from the left aortic arch (LAo) and the proximal and distal segments of the left pulmonary artery (LPAp and LPAd, respectively) change as body mass (Mb) increases. Eggs from common snapping turtles, Chelydra serpentina, were incubated under normoxia (21% O2; N21) or hypoxia (10% O2; H10), hatched and maintained in normoxia thereafter. Turtles (0.11-6.85 kg) were cannulated to measure arterial pressures, and an injection of adrenaline was used to increase pressures. Portions of the LAo, LPAp and LPAd were fixed under physiological hydrostatic pressures for histology and mechanical assessment. Arterial pressures increased with Mb for N21 but not for H10. Although mechanical and functional characteristics from the LPAp and LPAd were similar between N21 and H10, wall thickness from LAo did not change with Mb in the H10 group, thus wall stress increased in larger turtles. This indicates that larger H10 turtles probably experience an elevated probability of arterial wall rupture without concomitant changes in the cardiovascular system to prevent it. Finally, collagen content of the LPAp and LAo was smaller than in LPAd, suggesting a more distensible arterial wall could attenuate higher pressures from larger turtles.
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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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Filogonio R, Dubansky BD, Dubansky BH, Wang T, Elsey RM, Leite CAC, Crossley DA. Arterial wall thickening normalizes arterial wall tension with growth in American alligators, Alligator mississippiensis. J Comp Physiol B 2021; 191:553-562. [PMID: 33629153 DOI: 10.1007/s00360-021-01353-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/21/2021] [Accepted: 01/28/2021] [Indexed: 01/21/2023]
Abstract
Arterial wall tension increases with luminal radius and arterial pressure. Hence, as body mass (Mb) increases, associated increases in radius induces larger tension. Thus, it could be predicted that high tension would increase the potential for rupture of the arterial wall. Studies on mammals have focused on systemic arteries and have shown that arterial wall thickness increases with Mb and normalizes tension. Reptiles are good models to study scaling because some species exhibit large body size range associated with growth, thus, allowing for ontogenetic comparisons. We used post hatch American alligators, Alligator mississippiensis, ranging from 0.12 to 6.80 kg (~ 60-fold) to investigate how both the right aortic arch (RAo) and the left pulmonary artery (LPA) change with Mb. We tested two possibilities: (i) wall thickness increases with Mb and normalizes wall tension, such that stress (stress = tension/thickness) remains unchanged; (ii) collagen content scales with Mb and increases arterial strength. We measured heart rate and systolic and mean pressures from both systemic and pulmonary circulations in anesthetized animals. Once stabilized alligators were injected with adrenaline to induce a physiologically relevant increase in pressure. Heart rate decreased and systemic pressures increased with Mb; pulmonary pressures remained unchanged. Both the RAo and LPA were fixed under physiological hydrostatic pressures and displayed larger radius, wall tension and thickness as Mb increased, thus, stress was independent from Mb; relative collagen content was unchanged. We conclude that increased wall thickness normalizes tension and reduces the chances of arterial walls rupturing in large alligators.
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Affiliation(s)
- Renato Filogonio
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil.
| | - Benjamin D Dubansky
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX, 76203-5220, USA
| | - Brooke H Dubansky
- Department of Medical Laboratory Sciences and Public Health, Tarleton State University, Fort Worth, TX, USA
| | - Tobias Wang
- Section for Zoophysiology, Department of Biosciences, Aarhus University, 8000, Aarhus C, Denmark
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA, 70643, USA
| | - Cléo A C Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Dane A Crossley
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX, 76203-5220, USA
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