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Proaño-Bolaños C, Blasco-Zúñiga A, Almeida JR, Wang L, Llumiquinga MA, Rivera M, Zhou M, Chen T, Shaw C. Unravelling the Skin Secretion Peptides of the Gliding Leaf Frog, Agalychnis spurrelli (Hylidae). Biomolecules 2019; 9:E667. [PMID: 31671555 PMCID: PMC6920962 DOI: 10.3390/biom9110667] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022] Open
Abstract
Frog skin secretions contain medically-valuable molecules, which are useful for the discovery of new biopharmaceuticals. The peptide profile of the skin secretion of Agalychnis spurrelli has not been investigated; therefore, the structural and biological characterization of its compounds signify an inestimable opportunity to acquire new biologically-active chemical scaffolds. In this work, skin secretion from this amphibian was analysed by molecular cloning and tandem mass spectrometry. Although the extent of this work was not exhaustive, eleven skin secretion peptides belonging to five peptide families were identified. Among these, we report the occurrence of two phyllokinins, and one medusin-SP which were previously reported in other related species. In addition, eight novel peptides were identified, including four dermaseptins, DRS-SP2 to DRS-SP5, one phylloseptin-SP1, and three orphan peptides. Phylloseptin-SP1 and dermaseptins-SP2 were identified in HPLC fractions based on their molecular masses determined by MALDI-TOF MS. Among the antimicrobial peptides, dermaseptin-SP2 was the most potent, inhibiting Escherichia coli, Staphylococcus aureus, and ORSA with a minimum inhibitory concentration (MIC) of 2.68 μM, and Candida albicans with an MIC of 10.71 μM, without haemolytic effects. The peptides described in this study represent but a superficial glance at the considerable structural diversity of bioactive peptides produced in the skin secretion of A. spurrelli.
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Affiliation(s)
- Carolina Proaño-Bolaños
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK.
- Biomolecules Discovery Group, Laboratory of Molecular Biology and Biochemistry, Universidad Regional Amazónica Ikiam, km 7 ½ vía Muyuna, Tena 150150, Ecuador.
| | - Ailín Blasco-Zúñiga
- Laboratorio de Investigación en Citogenética y Biomoléculas de Anfibios (LICBA), Centro de Investigación para la Salud en América Latina (CISeAL), Pontificia Universidad Católica del Ecuador, Av 12 de Octubre 1076 y Roca, Quito 170150, Ecuador.
| | - José Rafael Almeida
- Biomolecules Discovery Group, Laboratory of Molecular Biology and Biochemistry, Universidad Regional Amazónica Ikiam, km 7 ½ vía Muyuna, Tena 150150, Ecuador.
| | - Lei Wang
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK.
| | - Miguel Angel Llumiquinga
- Laboratorio de Investigación en Citogenética y Biomoléculas de Anfibios (LICBA), Centro de Investigación para la Salud en América Latina (CISeAL), Pontificia Universidad Católica del Ecuador, Av 12 de Octubre 1076 y Roca, Quito 170150, Ecuador.
| | - Miryan Rivera
- Laboratorio de Investigación en Citogenética y Biomoléculas de Anfibios (LICBA), Centro de Investigación para la Salud en América Latina (CISeAL), Pontificia Universidad Católica del Ecuador, Av 12 de Octubre 1076 y Roca, Quito 170150, Ecuador.
| | - Mei Zhou
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK.
| | - Tianbao Chen
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK.
| | - Chris Shaw
- Natural Drug Discovery Group, School of Pharmacy, Queen's University, Belfast 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK.
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Larouche CB, Johnson R, Beaudry F, Mosley C, Gu Y, Zaman KA, Beaufrère H, Dutton C. Pharmacokinetics of midazolam and its major metabolite 1-hydroxymidazolam in the ball python (Python regius) after intracardiac and intramuscular administrations. J Vet Pharmacol Ther 2019; 42:722-731. [PMID: 31469454 DOI: 10.1111/jvp.12806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/07/2019] [Accepted: 07/31/2019] [Indexed: 11/28/2022]
Abstract
Midazolam is a benzodiazepine with sedative, muscle relaxant, anxiolytic, and anticonvulsant effects. Twelve ball pythons (Python regius) were used in a parallel study evaluating the pharmacokinetics of 1 mg/kg midazolam following a single intracardiac (IC) or intramuscular (IM) administration. Blood was collected from a central venous catheter placed 7 days prior, or by cardiocentesis, at 15 time points starting just prior to and up to 72 hr after drug administration. Plasma concentrations of midazolam and 1-hydroxymidazolam were determined by the use of high-performance liquid chromatography tandem-mass spectrometry and pharmacokinetic parameters were estimated using noncompartmental analysis. The mean ± SD terminal half-lives of IC and IM midazolam were 12.04 ± 3.25 hr and 16.54 ± 7.10 hr, respectively. The area under the concentration-time curve extrapolated to infinity, clearance, and apparent volume of distribution in steady-state of IC midazolam were 19,112.3 ± 3,095.9 ng*hr/ml, 0.053 ± 0.008 L hr-1 kg-1 , and 0.865 ± 0.289 L/kg, respectively. The bioavailability of IM midazolam was estimated at 89%. Maximum plasma concentrations following an IM administration were reached 2.33 ± 0.98 hr and 24.00 ± 14.12 hr postinjection for midazolam and 1-hydroxymidazolam, respectively, and 22.33 ± 20.26 hr postinjection for 1-hydroxymidazolam following IC administration.
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Affiliation(s)
- Cédric B Larouche
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.,Toronto Zoo, Toronto, Ontario, Canada
| | - Ron Johnson
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animale du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Craig Mosley
- VCA Canada, 404 Veterinary Emergency and Referral Hospital, Newmarket, Ontario, Canada
| | - Yu Gu
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Kristopher Afshaun Zaman
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Hugues Beaufrère
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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Yaw TJ, Mans C, Johnson SM, Doss GA, Sladky KK. Effect of injection site on alfaxalone-induced sedation in ball pythons (Python regius
). J Small Anim Pract 2018; 59:747-751. [DOI: 10.1111/jsap.12918] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/04/2018] [Accepted: 06/15/2018] [Indexed: 11/30/2022]
Affiliation(s)
- T. J. Yaw
- Department of Surgical Sciences, School of Veterinary Medicine; University of Wisconsin-Madison; 2015 Linden Drive, Madison Wisconsin 53706 USA
| | - C. Mans
- Department of Surgical Sciences, School of Veterinary Medicine; University of Wisconsin-Madison; 2015 Linden Drive, Madison Wisconsin 53706 USA
| | - S. M. Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine; University of Wisconsin-Madison; 2015 Linden Drive, Madison Wisconsin 53706 USA
| | - G. A. Doss
- Department of Surgical Sciences, School of Veterinary Medicine; University of Wisconsin-Madison; 2015 Linden Drive, Madison Wisconsin 53706 USA
| | - K. K. Sladky
- Department of Surgical Sciences, School of Veterinary Medicine; University of Wisconsin-Madison; 2015 Linden Drive, Madison Wisconsin 53706 USA
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Affiliation(s)
- James E. Bogan
- The Critter Fixer of Central Florida, LLC, 83 Geneva Drive, 621679, Oviedo, FL 32765, USA
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Crossley DA, Burggren WW, Reiber CL, Altimiras J, Rodnick KJ. Mass Transport: Circulatory System with Emphasis on Nonendothermic Species. Compr Physiol 2016; 7:17-66. [PMID: 28134997 DOI: 10.1002/cphy.c150010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mass transport can be generally defined as movement of material matter. The circulatory system then is a biological example given its role in the movement in transporting gases, nutrients, wastes, and chemical signals. Comparative physiology has a long history of providing new insights and advancing our understanding of circulatory mass transport across a wide array of circulatory systems. Here we focus on circulatory function of nonmodel species. Invertebrates possess diverse convection systems; that at the most complex generate pressures and perform at a level comparable to vertebrates. Many invertebrates actively modulate cardiovascular function using neuronal, neurohormonal, and skeletal muscle activity. In vertebrates, our understanding of cardiac morphology, cardiomyocyte function, and contractile protein regulation by Ca2+ highlights a high degree of conservation, but differences between species exist and are coupled to variable environments and body temperatures. Key regulators of vertebrate cardiac function and systemic blood pressure include the autonomic nervous system, hormones, and ventricular filling. Further chemical factors regulating cardiovascular function include adenosine, natriuretic peptides, arginine vasotocin, endothelin 1, bradykinin, histamine, nitric oxide, and hydrogen sulfide, to name but a few. Diverse vascular morphologies and the regulation of blood flow in the coronary and cerebral circulations are also apparent in nonmammalian species. Dynamic adjustments of cardiovascular function are associated with exercise on land, flying at high altitude, prolonged dives by marine mammals, and unique morphology, such as the giraffe. Future studies should address limits of gas exchange and convective transport, the evolution of high arterial pressure across diverse taxa, and the importance of the cardiovascular system adaptations to extreme environments. © 2017 American Physiological Society. Compr Physiol 7:17-66, 2017.
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Affiliation(s)
- Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Warren W Burggren
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Carl L Reiber
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Jordi Altimiras
- AVIAN Behavioral Genomics and Physiology, IFM Biology, Linköping University, Linköping, Sweden
| | - Kenneth J Rodnick
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
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Enok S, Leite GSPC, Leite CAC, Gesser H, Hedrick MS, Wang T. Improved cardiac filling facilitates the postprandial elevation of stroke volume in Python regius. ACTA ACUST UNITED AC 2016; 219:3009-3018. [PMID: 27445352 DOI: 10.1242/jeb.142729] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/18/2016] [Indexed: 01/10/2023]
Abstract
To accommodate the pronounced metabolic response to digestion, pythons increase heart rate and elevate stroke volume, where the latter has been ascribed to a massive and fast cardiac hypertrophy. However, numerous recent studies show that heart mass rarely increases, even upon ingestion of large meals, and we therefore explored the possibility that a rise in mean circulatory filling pressure (MCFP) serves to elevate venous pressure and cardiac filling during digestion. To this end, we measured blood flows and pressures in anaesthetized Python regius The anaesthetized snakes exhibited the archetypal tachycardia as well as a rise in both venous pressure and MCFP that fully account for the approximate doubling of stroke volume. There was no rise in blood volume and the elevated MCFP must therefore stem from increased vascular tone, possibly by means of increased sympathetic tone on the veins. Furthermore, although both venous pressure and MCFP increased during volume loading, there was no evidence that postprandial hearts were endowed with an additional capacity to elevate stroke volume. In vitro measurements of force development of paced ventricular strips also failed to reveal signs of increased contractility, but the postprandial hearts had higher activities of cytochrome oxidase and pyruvate kinase, which probably serves to sustain the rise in cardiac work during digestion.
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Affiliation(s)
- Sanne Enok
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus 8000, Denmark
| | - Gabriella S P C Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Paulo 13565-905, Brazil
| | - Cléo A C Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Paulo 13565-905, Brazil
| | - Hans Gesser
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus 8000, Denmark
| | - Michael S Hedrick
- Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, USA
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus 8000, Denmark
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7
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Zhang H, Wei L, Zou C, Bai JJ, Song Y, Liu H. Purification and Characterization of a Tachykinin-Like Peptide from Skin Secretions of the Tree Frog,Theloderma kwangsiensis. Zoolog Sci 2013; 30:529-33. [DOI: 10.2108/zsj.30.529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Barreto S, Chaguri L, Prezoto B, Lebrun I. Characterization of two vasoactive peptides isolated from the plasma of the snake Crotalus durissus terrificus. Biomed Pharmacother 2012; 66:256-65. [DOI: 10.1016/j.biopha.2011.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 10/31/2011] [Indexed: 11/26/2022] Open
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Barboza PS, Bennett A, Lignot JH, Mackie RI, McWhorter TJ, Secor SM, Skovgaard N, Sundset MA, Wang T. Digestive challenges for vertebrate animals: microbial diversity, cardiorespiratory coupling, and dietary specialization. Physiol Biochem Zool 2010; 83:764-74. [PMID: 20578844 DOI: 10.1086/650472] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The digestive system is the interface between the supply of food for an animal and the demand for energy and nutrients to maintain the body, to grow, and to reproduce. Digestive systems are not morphologically static but rather dynamically respond to changes in the physical and chemical characteristics of the diet and the level of food intake. In this article, we discuss three themes that affect the ability of an animal to alter digestive function in relation to novel substrates and changing food supply: (1) the fermentative digestion in herbivores, (2) the integration of cardiopulmonary and digestive functions, and (3) the evolution of dietary specialization. Herbivores consume, digest, and detoxify complex diets by using a wide variety of enzymes expressed by bacteria, predominantly in the phyla Firmicutes and Bacteroidetes. Carnivores, such as snakes that feed intermittently, sometimes process very large meals that require compensatory adjustments in blood flow, acid secretion, and regulation of acid-base homeostasis. Snakes and birds that specialize in simple diets of prey or nectar retain their ability to digest a wider selection of prey. The digestive system continues to be of interest to comparative physiologists because of its plasticity, both phenotypic and evolutionary, and because of its widespread integration with other physiological systems, including thermoregulation, circulation, ventilation, homeostasis, immunity, and reproduction.
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Affiliation(s)
- P S Barboza
- Department of Biology and Wildlife, University of Alaska, Fairbanks, AK 99775, USA.
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Jourdan‐Pineau H, Dupont‐Prinet A, Claireaux G, McKenzie D. An Investigation of Metabolic Prioritization in the European Sea Bass, Dicentrarchus labrax. Physiol Biochem Zool 2010; 83:68-77. [DOI: 10.1086/648485] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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11
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Barreto SA, Chaguri LCAG, Prezoto BC, Lebrun I. Effects of three vasoactive peptides isolated from the plasma of the snake Bothrops jararaca. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:552-8. [PMID: 19358335 DOI: 10.1016/j.cbpc.2008.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Incubation of plasma from the snake Bothrops jararaca (BJP) with trypsin generated two hypotensive peptides. The primary structure of the peptides was established for three sequences as: Asn-Pro-Phe-Val-Asp-Ala (fraction 13), Ser-Lys-Pro-Asn-Met-Ser-Asp-Glu-Ser-Leu-Ala-Val-Ala-Ile (fraction 14), Asn-Pro-Phe- Val-Asp-Ala (fraction 15). These peptides display homology with fragments of albumin from Trimeresurus flavoviridis. A bolus intra-arterial injection of the purified or the synthetic peptide produced a strong and sustained vasopressor response in the anaesthetized snake B. jararaca and Wistar rats; this hypotensive effect was also potentiated by captopril, an angiotensin-converting enzyme inhibitor (0.1 mg/kg). The natural concentrations of these peptides in plasma need to be determined and could play a physiological role in snake blood pressure regulation.
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Affiliation(s)
- S A Barreto
- Biochemistry and Biophysics Laboratory, Butantan Institute, São Paulo, SP, Brazil
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12
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Skovgaard N, Møller K, Gesser H, Wang T. Histamine induces postprandial tachycardia through a direct effect on cardiac H2-receptors in pythons. Am J Physiol Regul Integr Comp Physiol 2009; 296:R774-85. [DOI: 10.1152/ajpregu.90466.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intrinsic heart rate of most vertebrates studied, including humans, is elevated during digestion, suggesting that a nonadrenergic-noncholinergic factor contributes to the postprandial tachycardia. The regulating factor, however, remains elusive and difficult to identify. Pythons can ingest very large meals, and digestion is associated with a marked rise in metabolism that is sustained for several days. The metabolic rise causes more than a doubling of heart rate and a fourfold rise in cardiac output. This makes the python an interesting model to investigate the postprandial tachycardia. We measured blood pressure and heart rate in fasting Python regius, and at 24 and 48 h after ingestion of a meal amounting to 25% of body wt. Digestion caused heart rate to increase from 25 to 56 min, whereas blood pressure was unchanged. The postprandial rise in heart rate was partially due to a doubling of intrinsic heart rate. The H2-antagonist did not affect heart rate of fasting snakes but decreased heart rate by 15–20 min at 24 h into digestion, whereas it had no effects at 48 h. Thus, the histaminergic tone on the heart rose from none to 30% at 24 h but vanished after 48 h. In anesthetized snakes, histamine caused a systemic vasodilatation and a marked increase in heart rate and cardiac output mediated through a direct effect on H2- receptors. Our study strongly indicates that histamine regulates heart rate during the initial phase of digestion in pythons. This study describes a novel regulation of the vertebrate heart.
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13
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Olesen MG, Bertelsen MF, Perry SF, Wang T. Effects of preoperative administration of butorphanol or meloxicam on physiologic responses to surgery in ball pythons. J Am Vet Med Assoc 2008; 233:1883-8. [DOI: 10.2460/javma.233.12.1883] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Breno MC, Prezoto BC, Borgheresi RAMB, Lazari MFM, Yamanouye N. Characteristics of neural and humoral systems involved in the regulation of blood pressure in snakes. Comp Biochem Physiol A Mol Integr Physiol 2007; 147:766-778. [PMID: 17046304 DOI: 10.1016/j.cbpa.2006.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 09/04/2006] [Accepted: 09/05/2006] [Indexed: 12/22/2022]
Abstract
Cardiovascular function is affected by many mechanisms, including the autonomic system, the kallikrein-kinin system (KKS), the renin-angiotensin system (RAS) and the endothelin system. The function of these systems seems to be fairly well preserved throughout the vertebrate scale, but evolution required several adaptations. Snakes are particularly interesting for studies related to the cardiovascular function because of their elongated shape, their wide variation in size and length, and because they had to adapt to extremely different habitats and gravitational influences. To keep the normal cardiovascular control the snakes developed anatomical and functional adaptations and interesting structural peculiarities are found in their autonomic, KKS, RAS and endothelin systems. Our laboratory has characterized some biochemical, pharmacological and physiological properties of these systems in South American snakes. This review compares the components and function of these systems in snakes and other vertebrates, and focuses on differences found in snakes, related with receptor or ligand structure and/or function in autonomic system, RAS and KKS, absence of components in KKS and the intriguing identity between a venom and a plasma component in the endothelin system.
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Affiliation(s)
- Maria Cristina Breno
- Laboratório de Farmacologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil.
| | - Benedito Carlos Prezoto
- Laboratório de Farmacologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
| | - Rosa A M B Borgheresi
- Laboratório de Farmacologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
| | - Maria Fátima M Lazari
- Departamento de Farmacologia, Setor Endocrinologia Experimental, Universidade Federal de São Paulo, Rua 3 de maio,100, 04044-020, São Paulo, SP, Brazil
| | - Norma Yamanouye
- Laboratório de Farmacologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
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15
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Conlon JM, Jouenne T, Cosette P, Cosquer D, Vaudry H, Taylor CK, Abel PW. Bradykinin-related peptides and tryptophyllins in the skin secretions of the most primitive extant frog, Ascaphus truei. Gen Comp Endocrinol 2005; 143:193-9. [PMID: 15922344 DOI: 10.1016/j.ygcen.2005.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 03/10/2005] [Accepted: 04/12/2005] [Indexed: 10/25/2022]
Abstract
The tailed frog Ascaphus truei occupies a unique position in phylogeny as the most primitive extant anuran and is regarded as the sister taxon to the clade of all other living frogs. A previous study led to the isolation of eight antimicrobial peptides, termed ascaphins, from norepinephrine-stimulated skin secretions. Peptidomic analysis (HPLC separation followed by MALDI mass spectrometry and Edman degradation) of these secretions has led to the identification and structural characterization of 13 additional peptides present in relatively high concentration. In addition to bradykinin (BK; RPPGFSPFR), a C-terminally extended bradykinin (peptide RD-11; RPPGFSPFRVD), a bradykinin-like peptide (peptide AR-10; APVPGLSPFR), and a C-terminally extended form of this peptide (peptide AV-12; APVPGLSPFRVV) were obtained in pure form. These peptides produced concentration-dependent relaxation of precontracted mouse tracheal rings with a rank order of potency of BK>RD-11>AR-10>AV-12 but only RD-11 caused the same maximal relaxation as bradykinin. Four small peptides were also isolated from the skin secretions that contain the Pro-Trp motif that is a characteristic of the tryptophyllin family of peptides previously identified in skins of frogs of the family Hylidae. The data show that the synthesis of dermal peptides that may play a role in defense against predators arose early in the evolution of anurans.
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Affiliation(s)
- J Michael Conlon
- Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al-Ain, United Arab Emirates.
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16
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Galli GLJ, Skovgaard N, Abe AS, Taylor EW, Conlon JM, Wang T. Cardiovascular actions of rattlesnake bradykinin ([Val1,Thr6]bradykinin) in the anesthetized South American rattlesnakeCrotalus durissus terrificus. Am J Physiol Regul Integr Comp Physiol 2005; 288:R456-65. [PMID: 15498967 DOI: 10.1152/ajpregu.00417.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Incubation of heat-denatured plasma from the rattlesnake Crotalus atrox with trypsin generated a bradykinin (BK) that contained two amino acid substitutions (Arg1→ Val and Ser6→ Thr) compared with mammalian BK. Bolus intra-arterial injections of synthetic rattlesnake BK (0.01–10 nmol/kg) into the anesthetized rattlesnake, Crotalus durissus terrificus, produced a pronounced and concentration-dependent increase in systemic vascular conductance (Gsys). This caused a fall in systemic arterial blood pressure (Psys) and an increase in blood flow. Heart rate and stroke volume also increased. This primary response was followed by a significant rise in Psys and pronounced tachycardia (secondary response). Pretreatment with NG-nitro-l-arginine methyl ester reduced the NK-induced systemic vasodilatation, indicating that the effect is mediated through increased NO synthesis. The tachycardia associated with the late primary and secondary response to BK was abolished with propranolol and the systemic vasodilatation produced in the primary phase was also significantly attenuated by pretreatment, indicating that the responses are caused, at least in part, by release of cathecholamines and subsequent stimulation of β-adrenergic receptors. In contrast, the pulmonary circulation was relatively unresponsive to BK.
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Affiliation(s)
- Gina L J Galli
- Department of Zoophysiology, Aarhus University, Aarhus, Denmark.
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17
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Wang T, Altimiras J, Axelsson M. Intracardiac flow separation in anin situperfused heart from Burmese pythonPython molurus. J Exp Biol 2002; 205:2715-23. [PMID: 12151377 DOI: 10.1242/jeb.205.17.2715] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe heart of non-crocodilian reptiles has two separate atria that receive blood from the systemic and pulmonary circulations. The ventricle is not fully divided, but is compartmentalised into two chambers (cavum dorsale and cavum pulmonale) by a muscular ridge that runs from the apex to the base of the ventricle. The muscular ridge is small in turtles, but is well developed in varanid lizards and many species of snakes. These anatomical differences correlate with an effective blood flow separation in varanid lizards, whereas turtles can exhibit very large cardiac shunts. Very little is known about the cardiac shunt patterns in other groups of reptiles.Here we characterise cardiac performance and flow dynamics in the Burmese python (Python molurus) using an in situ perfused heart preparation. The pericardium remained intact and the two atria were perfused separately (Ringer solution), and the two systemic and the pulmonary outflows were independently cannulated. Right and left atrial filling pressures and ventricular outflow pressures of the pulmonary and systemic vessels could be manipulated independently, permitting the establishment of large experimental intraventricular pressure gradients across the muscular ridge. The maximal power output generated by the systemic side of the ventricle exceeded the maximal power output that was generated by the cavum pulmonale that perfuse the pulmonary circulation. Furthermore, systemic flow could be generated against a higher outflow pressure than pulmonary flow. Perfusate entering the right atrium was preferentially distributed into the pulmonary circulation,whereas perfusate into the left atrium was distributed to the systemic circulation.Our study indicates that the well-developed muscular ridge can separate the cavum systemic and pulmonary sides of the heart to prevent mixing of systemic and pulmonary flows. Therefore, the heart of Python appears to exhibit a large degree of ventricular flow separation as previously described for varanid lizards. We speculate that the ventricular separation has evolved in response to the need of maintaining high oxygen delivery while protecting the pulmonary circulation from oedema as result of high vascular pressures.
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Affiliation(s)
- Tobias Wang
- Department of Zoophysiology, University of Aarhus, 8000 Aarhus C, Denmark.
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Wang T, Taylor EW, Andrade D, Abe AS. Autonomic control of heart rate during forced activity and digestion in the snakeBoa constrictor. J Exp Biol 2001; 204:3553-60. [PMID: 11707504 DOI: 10.1242/jeb.204.20.3553] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
SUMMARYReptiles, particularly snakes, exhibit large and quantitatively similar increments in metabolic rate during muscular exercise and following a meal, when they are apparently inactive. The cardiovascular responses are similar during these two states, but the underlying autonomic control of the heart remains unknown. We describe both adrenergic and cholinergic tonus on the heart during rest, during enforced activity and during digestion (24–36 h after ingestion of 30 % of their body mass) in the snake Boa constrictor. The snakes were equipped with an arterial catheter for measurements of blood pressure and heart rate, and autonomic tonus was determined following infusion of the β-adrenergic antagonist propranolol (3 mg kg–1) and the muscarinic cholinoceptor antagonist atropine (3 mg kg–1).The mean heart rate of fasting animals at rest was 26.4±1.4 min–1, and this increased to 36.1±1.4 min–1 (means ± s.e.m.; N=8) following double autonomic block (atropine and propranolol). The calculated cholinergic and adrenergic tones were 60.1±9.3 % and 19.8±2.2 %, respectively. Heart rate increased to 61.4±1.5 min–1 during enforced activity, and this response was significantly reduced by propranolol (maximum values of 35.8±1.6 min–1), but unaffected by atropine. The cholinergic and adrenergic tones were 2.6±2.2 and 41.3±1.9 % during activity, respectively. Double autonomic block virtually abolished tachycardia associated with enforced activity (heart rate increased significantly from 36.1±1.4 to 37.6±1.3 min–1), indicating that non-adrenergic, non-cholinergic effectors are not involved in regulating heart rate during activity. Blood pressure also increased during activity.Digestion was accompanied by an increase in heart rate from 25.6±1.3 to 47.7±2.2 min–1 (N=8). In these animals, heart rate decreased to 44.2±2.7 min–1 following propranolol infusion and increased to 53.9±1.8 min–1 after infusion of atropine, resulting in small cholinergic and adrenergic tones (6.0±3.5 and 11.1±1.1 %, respectively). The heart rate of digesting snakes was 47.0±1.0 min–1 after double autonomic blockade, which is significantly higher than the value of 36.1±1.4 min–1 in double-blocked fasting animals at rest. Therefore, it appears that some other factor exerts a positive chronotropic effect during digestion, and we propose that this factor may be a circulating regulatory peptide, possibly liberated from the gastrointestinal system in response to the presence of food.
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Affiliation(s)
- T Wang
- Department of Zoology, UNESP Rio Claro, Brazil.
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Takei Y, Tsuchida T, Li Z, Conlon JM. Antidipsogenic effects of eel bradykinins in the eel Anguilla japonica. Am J Physiol Regul Integr Comp Physiol 2001; 281:R1090-6. [PMID: 11557614 DOI: 10.1152/ajpregu.2001.281.4.r1090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A peptide with bradykinin (BK)-like immunoreactivity was isolated from an incubate of heat-denatured eel plasma with porcine pancreatic kallikrein. The purified peptide had the following amino acid sequence: Arg-Arg-Pro-Pro-Gly-Ser-Trp-Pro-Leu-Arg. This decapeptide, named eel [Arg(0)]BK, was identical to two previously identified BK homologs from cod and trout. High conservation of the BK sequence among distant teleost species suggests an important function in this vertebrate group. Bolus intra-arterial injections of eel [Arg(0)]BK, BK, and [Arg(0)]-des-Arg(9)-BK (1-10 nmol/kg) caused significant (P < 0.05) inhibition of drinking in seawater-adapted eels. The potency of the inhibition was ranked in the following order: [Arg(0)]BK > [Arg(0)]-des-Arg(9)-BK = BK. The BK peptides also produced an immediate, transient increase followed by a sustained increase in arterial blood pressure and an initial decrease followed by an increase in heart rate. Strong tachyphylaxis occurred for the cardiovascular effect but not for the antidipsogenic effect. The order of the potency of the cardiovascular actions, [Arg(0)]BK > BK > [Arg(0)]-des-Arg(9)-BK, was different from that of the antidipsogenic action. Slow infusions of eel [Arg(0)]BK in the dose range 1-1,000 pmol x kg(-1) x min(-1) produced concentration-dependent inhibition of drinking without changes in arterial pressure, plasma osmolality, and hematocrit. At the infusion rate of >100 pmol x kg(-1) x min(-1), plasma concentrations of angiotensin II, a potent dipsogenic hormone in eels, increased, suggesting an interaction of the kallikrein-kinin and renin-angiotensin systems. In mammals, BK is dipsogenic and vasodepressor, so that our data demonstrate opposite effects on fluid and cardiovascular regulation of BK in the eel and suggest a new physiological role for the kallikrein-kinin system in teleost fish.
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Affiliation(s)
- Y Takei
- Department of Marine Bioscience, Ocean Research Institute, University of Tokyo, Nakano, Tokyo 164-8639, Japan.
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