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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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Campos R, Justo AFO, Jacintho FF, Mónica FZ, Rojas-Moscoso JA, Moreno RA, Napolitano M, Cogo JC, De Nucci G. Pharmacological and transcriptomic characterization of the nitric oxide pathway in aortic rings isolated from the tortoise Chelonoidis carbonaria. Comp Biochem Physiol C Toxicol Pharmacol 2019; 222:82-89. [PMID: 31028932 DOI: 10.1016/j.cbpc.2019.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 11/29/2022]
Abstract
In this study the nitric oxide (NO)-soluble guanylate cyclase (sGC) and phosphodiesterase-5 (PDE-5) pathway was characterized in tortoise Chelonoidis carbonaria aorta. Concentration response curves (CCR) to ATP, ADP, AMP, adenosine and histamine were performed in the presence and absence of L-NAME in aorta pre-contracted with ACh (3 μM). CCR to SNP, BAY 41-2272 (sGC stimulator), BAY 60-2770 (sGC activator) and tadalafil (PDE-5 inhibitor) were constructed in the presence and absence of ODQ (10 μM). ATP (pEC50 6.1 ± 0.1), ADP (pEC50 6.0 ± 0.2), AMP (pEC50 6.8 ± 0.1) and histamine (pEC50 6.8 ± 0.12) relaxed Chelonoidis aorta and the addition of L-NAME reduced their efficacy (p < .05). Adenosine effects (pEC50 6.6 ± 0.1) were not changed in the presence of L-NAME. SNP (pEC50 7.5 ± 0.7; Emax 102.2 ± 2.5%), BAY 41-2272 (pEC50 7.3 ± 0.2; Emax 130.3 ± 10.2%), BAY 60-2770 (pEC50 11.4 ± 0.1; Emax 130.3 ± 6.5%) and tadalafil (pEC50 6.7 ± 0.3; Emax 121.3 ± 15.3%) relaxed Chelonoidis aorta. The addition of ODQ reduced the SNP and tadalafil maximum response (p < .05) and promoted 63 fold right shift on BAY 41-2272 curve. In contrast, no alteration was observed on BAY 60-2770 response. Transcriptomic analysis for eNOS and sGC were found in aorta and brain libraries with high homology when compared with human transcripts. The NO-sGC-PDE-5 is functionally present in Chelonoidis aorta with a functional and genomic similarity to mammalian vessels. Unlike most of mammalian vessels, ACh did not cause endothelium-dependent relaxation in Chelonoidis carbonaria aortic rings.
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Affiliation(s)
- Rafael Campos
- Superior Institute of Biomedical Sciences, Ceará State University (UECE), Fortaleza, Brazil; Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil.
| | | | - Felipe Fernandes Jacintho
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Fabiola Z Mónica
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | | | - Ronilson Agnaldo Moreno
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Mauro Napolitano
- Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - José Carlos Cogo
- Faculty of Biomedical Engineering, Brazil University, Itaquera, Brazil
| | - Gilberto De Nucci
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil; Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
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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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Characterisation and vascular expression of nitric oxide synthase 3 in amphibians. Cell Tissue Res 2016; 366:679-692. [PMID: 27543051 DOI: 10.1007/s00441-016-2479-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 07/11/2016] [Indexed: 01/10/2023]
Abstract
In mammals, nitric oxide (NO) produced by nitric oxide synthase 3 (NOS3) localised in vascular endothelial cells is an important vasodilator but the presence of NOS3 in the endothelium of amphibians has been concluded to be absent, based on physiological studies. In this study, a nos3 cDNA was sequenced from the toad, Rhinella marina. The open reading frame of R. marina nos3 encoded an 1170 amino acid protein that showed 81 % sequence identity to the recently cloned Xenopus tropicalis nos3. Rhinella marina nos3 mRNA was expressed in a range of tissues and in the dorsal aorta and pulmonary, mesenteric, iliac and gastrocnemius arteries. Furthermore, nos3 mRNA was expressed in the aorta of Xenopus laevis and X. tropicalis. Quantitative real-time PCR showed that removal of the endothelium of the lateral aorta of R. marina significantly reduced the expression of nos3 mRNA compared to control aorta with the endothelium intact. However, in situ hybridisation was not able to detect any nos3 mRNA in the dorsal aorta of R. marina. Immunohistochemistry using a homologous R. marina NOS3 antibody showed immunoreactivity (IR) within the basal region of many endothelial cells of the dorsal aorta and iliac artery. NOS3-IR was also observed in the proximal tubules and collecting ducts of the kidney but not within the capillaries of the glomeruli. This is the first study to demonstrate that vascular endothelial cells of an amphibian express NOS3.
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The evolution of nitric oxide signalling in vertebrate blood vessels. J Comp Physiol B 2014; 185:153-71. [DOI: 10.1007/s00360-014-0877-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/06/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022]
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Mechanisms of acetylcholine-mediated vasodilation in systemic arteries from mourning doves (Zenaida macroura). J Comp Physiol B 2013; 183:959-67. [DOI: 10.1007/s00360-013-0757-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 01/07/2023]
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Mónica FZ, Rojas-Moscoso J, Porto M, Schenka AA, Antunes E, Cogo JC, De Nucci G. Immunohistochemical and functional characterization of nitric oxide signaling pathway in isolated aorta from Crotalus durissus terrificus. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:433-9. [PMID: 22134054 DOI: 10.1016/j.cbpc.2011.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/07/2011] [Accepted: 11/09/2011] [Indexed: 11/19/2022]
Abstract
We characterized the nitric oxide (NO)-cyclic GMP-phosphodiesterase-5 (PDE5) pathway in Crotalus durissus terrificus aorta. Concentration responses curves to acetylcholine (ACh), sodium nitroprusside (SNP), BAY41-2272 (soluble guanylyl cyclase [sGC] stimulator), BAY60-2770 (sGC activator) and tadalafil (PDE5 inhibitor) were constructed in phenylephrine (10 μM)-precontracted tissues with intact (E(+)) or denuded (E(-)) endothelium. ACh (0.0001-10 μM) and SNP (0.0001-10 μM) relaxed aorta, which were reduced by the NO synthase (L-NAME,100 μM) or the sGC inhibitors (ODQ, 10 μM). Tadalafil (0.0001-10 μM) relaxed E(+) rings with potency (pEC(50)) and maximal response (E(max)) values of 7.34±0.02 and 105±8%, respectively. E(-) or ODQ treatment significantly (P<0.05) reduced tadalafil relaxations (66±18% and 71±7%, respectively). BAY41-2272 (0.0001-300 nM) produced concentration-dependent relaxations in E(+) rings, which were reduced by addition of either ODQ or L-NAME (16.0- and 5.2-fold rightward shifts, respectively). The relaxation of BAY60-2770 was markedly potentiated by ODQ and L-NAME (41.0- and 9.7-fold leftward shifts, respectively), whereas in E(-) the pEC(50) values were shifted by 7-fold to the right. Immunohistochemistry, followed validation by transcriptomic analysis, revealed the presence of eNOS in endothelium, whereas nNOS was observed only in perivascular nerves. sGC and PDE5 were expressed in smooth muscle. Thus, NO-sGC-PDE5 pathway is evolutionarily present in Crotalus sp. vessels, and has a remarkable degree of functional similarity to mammalian vessels.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Aorta/physiology
- Carbolines/pharmacology
- Crotalus/genetics
- Crotalus/metabolism
- Crotalus/physiology
- Cyclic Nucleotide Phosphodiesterases, Type 5/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiology
- Gene Expression Profiling
- Guanylate Cyclase/antagonists & inhibitors
- Guanylate Cyclase/metabolism
- Immunohistochemistry/methods
- In Vitro Techniques
- Male
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type III/genetics
- Nitric Oxide Synthase Type III/metabolism
- Nitroprusside/pharmacology
- Phenylephrine/pharmacology
- Pyrazoles/pharmacology
- Pyridines/pharmacology
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/metabolism
- Signal Transduction
- Soluble Guanylyl Cyclase
- Tadalafil
- Vasodilation
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Affiliation(s)
- Fabíola Z Mónica
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), SP, Brazil.
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Trajanovska S, Donald JA. Endothelial nitric oxide synthase in the amphibian, Xenopus tropicalis. Comp Biochem Physiol B Biochem Mol Biol 2011; 158:274-81. [PMID: 21199680 DOI: 10.1016/j.cbpb.2010.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 12/19/2010] [Accepted: 12/22/2010] [Indexed: 11/19/2022]
Abstract
Nitric oxide (NO) is generated by NO synthase (NOS) of which there are three isoforms: neuronal NOS (nNOS, nos1), inducible NOS (iNOS, nos2), and endothelial NOS (eNOS, nos3). This study utilised the genome of Xenopus tropicalis to sequence a nos3 cDNA and determine if eNOS protein is expressed in blood vessels. A nos3 cDNA was sequenced that encoded a 1177 amino acid protein called XteNOS, which showed closest sequence identity to mammalian eNOS protein. The X. tropicalis nos3 gene and eNOS protein were determined to be an orthologue of mammalian nos3 and eNOS using gene synteny and phylogenetic analyses, respectively. In X. tropicalis, nos3 mRNA expression was highest in lung and skeletal muscle and lower in the liver, gut, kidney, heart and brain. Western analysis of kidney protein using an affinity-purified anti-XteNOS produced a single band at 140kDa. Immunohistochemistry showed XteNOS immunoreactivity in the proximal tubule of the kidney and endocardium of the heart, but not in the endothelium of blood vessels. Thus, X. tropicalis has a nos3 gene that appears not to be expressed in the vascular endothelium.
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Affiliation(s)
- Sofie Trajanovska
- School of Life and Environmental Sciences, Deakin University, Geelong, 3217, Australia.
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Olson KR, Donald JA. Nervous control of circulation--the role of gasotransmitters, NO, CO, and H2S. Acta Histochem 2009; 111:244-56. [PMID: 19128825 DOI: 10.1016/j.acthis.2008.11.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The origins and actions of gaseous signaling molecules, nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H(2)S) in the mammalian cardiovascular system have received considerable attention and it is evident that these three "gasotransmitters" perform a variety of homeostatic functions. The origins, actions and disposition of these gasotransmitters in the piscine vasculature are far from resolved. In most fish examined to date, NO or NO donors are generally in vitro and in vivo vasodilators acting via soluble guanylyl cyclase, although there is evidence for NO-mediated vasoconstriction. Injection of sodium nitroprusside into trout causes hypotension that is attributed to a reduction in systemic resistance. Unlike mammals, NO does not appear to have an endothelial origin in fish blood vessels as an endothelial NO synthase has not identified. However, neural NO synthase is prevalent in perivascular nerves and is the most likely source of NO for cardiovascular control in fish. CO is a vasodilator in lamprey and trout vessels, and it, like NO, appears to exert its action, at least in part, via guanylyl cyclase and potassium channel activation. Inhibition of CO production increases resting tone in trout vessels suggestive of tonic CO activity, but little else is known about the origin or control of CO in the fish vasculature. H(2)S is synthesized by fish vessels and its constrictory, dilatory, or even multi-phasic actions, are both species- and vessel-specific. A small component of H(2)S-mediated basal activity may be endothelial in origin, but to a large extent H(2)S affects vascular smooth muscle directly and the mechanisms are unclear. H(2)S injected into the dorsal aorta of unanesthetized trout often produces oscillations in arterial blood pressure suggestive of H(2)S activity in the central nervous system as well as peripheral vasculature. Collectively, these studies hint at significant involvement of the gasotransmitters in piscine cardiovascular function and hopefully provide a variety of avenues for future research.
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Affiliation(s)
- Kenneth R Olson
- Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA.
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Jennings BL, Donald JA. Neurally-derived nitric oxide regulates vascular tone in pulmonary and cutaneous arteries of the toad,Bufo marinus. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1640-6. [DOI: 10.1152/ajpregu.00057.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this study, the role of nitric oxide (NO) in regulation of the pulmocutaneous vasculature of the toad, Bufo marinus was investigated. In vitro myography demonstrated the presence of a neural NO signaling mechanism in both arteries. Vasodilation induced by nicotine was inhibited by the soluble guanylyl cyclase (GC) inhibitor, 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, and the NO synthase (NOS) inhibitor, Nω-nitro-l-arginine (l-NNA). Removal of the endothelium had no significant effect on the vasodilation. Furthermore, pretreatment with N5-(1-imino-3-butenyl)-l-ornithine (vinyl-l-NIO), a more specific inhibitor of neural NOS, caused a significant decrease in the nicotine-induced dilation. In the pulmonary artery only, a combination of l-NNA and the calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP(8-37), completely blocked the nicotine-induced dilation. In both arteries, the vasodilation was also significantly decreased by glibenclamide, an ATP-sensitive K+(K+ATP) channel inhibitor. Levcromakalim, a K+ATPchannel opener, caused a dilation that was blocked by glibenclamide in both arteries. In the pulmonary artery, NO donor-mediated dilation was significantly decreased by pretreatment with glibenclamide. The physiological data were supported by NADPH-diaphorase histochemistry and immunohistochemistry, which demonstrated NOS in perivascular nerve fibers but not the endothelium of the arteries. These results indicate that the pulmonary and cutaneous arteries of B. marinus are regulated by NO from nitrergic nerves rather than NO released from the endothelium. The nitrergic vasodilation in the arteries appears to be caused, in part, via activation of K+ATPchannels. Thus, NO could play an important role in determining pulmocutaneous blood flow and the magnitude of cardiac shunting.
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Skovgaard N, Zibrandtsen H, Laursen BE, Simonsen U, Wang T. Hypoxia-induced vasoconstriction in alligator (Alligator mississippiensis) intrapulmonary arteries: a role for endothelin-1? J Exp Biol 2008; 211:1565-70. [DOI: 10.1242/jeb.014662] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Hypoxic pulmonary vasoconstriction (HPV) is an adaptive response that diverts pulmonary blood flow from poorly ventilated and hypoxic areas of the lung to better ventilated parts, matching blood perfusion to ventilation. HPV is an ancient and highly conserved response expressed in the respiratory organs of all vertebrates. However, the underlying mechanism and the role of the endothelium remain elusive. Isolated intrapulmonary arteries (internal diameter <346 μm) from the American alligator Alligator mississippiensis were mounted in microvascular myographs for isometric tension recording. Resting vessels and vessels contracted with either serotonin (5-HT) or endothelin-1 (ET-1) were exposed to sustained (45 min)hypoxia (PO2<5 mmHg). In ET-1-contracted vessels, hypoxia induced a monophasic, sustained and fully reversible constriction, which was independent of the endothelium. In relaxed or in 5-HT-contracted vessels, hypoxia did not cause constriction. The effects of ET-1, ETA and ETB as well as the general ET-receptor antagonist were studied. ET-1 caused a contraction of the pulmonary arteries through stimulation of ETA-receptors. ETA and ETB immunoreactive staining revealed the location of both receptors in the smooth muscle layer and of ETB receptors in the endothelium. In conclusion, because precontraction with serotonin did not facilitate HPV,the required precontraction in alligators seems specific to ET-1, which implies that ET-1 plays an important permissive role for the HPV response in alligators.
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Affiliation(s)
- Nini Skovgaard
- Zoophysiology, Department of Biological Sciences, University of Aarhus,Building 1131, 8000 Aarhus C, Denmark
- Department of Pharmacology, University of Aarhus, Denmark
| | | | | | - Ulf Simonsen
- Department of Pharmacology, University of Aarhus, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Biological Sciences, University of Aarhus,Building 1131, 8000 Aarhus C, Denmark
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Merchant M, Williams S, Trosclair PL, Elsey RM, Mills K. Febrile response to infection in the American alligator (Alligator mississippiensis). Comp Biochem Physiol A Mol Integr Physiol 2007; 148:921-5. [DOI: 10.1016/j.cbpa.2007.09.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 09/27/2007] [Accepted: 09/27/2007] [Indexed: 10/22/2022]
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Jennings BL, Bell JD, Hyodo S, Toop T, Donald JA. Mechanisms of vasodilation in the dorsal aorta of the elephant fish, Callorhinchus milii (Chimaeriformes: Holocephali). J Comp Physiol B 2007; 177:557-67. [PMID: 17342492 DOI: 10.1007/s00360-007-0154-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 01/28/2007] [Accepted: 02/12/2007] [Indexed: 10/23/2022]
Abstract
This study investigated vasodilator mechanisms in the dorsal aorta of the elephant fish, Callorhinchus milii, using anatomical and physiological approaches. Nitric oxide synthase could only be located in the perivascular nerve fibres and not the endothelium of the dorsal aorta, using NADPH histochemistry and immunohistochemistry. In vitro organ bath experiments demonstrated that a NO/soluble guanylyl cyclase (GC) system appeared to be absent in the vascular smooth muscle, since the NO donors SNP (10(-4) mol l(-1)) and SIN-1 (10(-5) mol l(-1)) were without effect. Nicotine (3 x 10(-4) mol l(-1)) mediated a vasodilation that was not affected by ODQ (10(-5) mol l(-1)), L-NNA (10(-4) mol l(-1)), indomethacin (10(-5) mol l(-1)), or removal of the endothelium. In contrast, the voltage-gated sodium channel inhibitor, tetrodotoxin (10(-5) mol l(-1)), significantly decreased the dilation induced by nicotine, suggesting that it contained a neural component. Pre-incubation of the dorsal aorta with the calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP(8-37) (10(-6) mol l(-1)) also caused a significant decrease in the nicotine-induced dilation. We propose that nicotine is mediating a neurally-derived vasodilation in the dorsal aorta that is independent of NO, prostaglandins and the endothelium, and partly mediated by CGRP.
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Affiliation(s)
- Brett L Jennings
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC, 3217, Australia.
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