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Auteur Blasco, F.R.; McKenzie, D.J.; Taylor, E.W.; Rantin, F.T. doi  openurl
  Titre The role of the autonomic nervous system in control of cardiac and air-breathing responses to sustained aerobic exercise in the African sharptooth catfish Clarias gariepinus Type Article scientifique
  Année 2017 Publication Revue Abrégée Comp. Biochem. Physiol. A-Mol. Integr. Physiol.  
  Volume 203 Numéro Pages 273-280  
  Mots-Clés Adrenergic tone; bass dicentrarchus-labrax; cardiorespiratory interactions; Cholinergic tone; Fishes; Heart rate; heart-rate; hoplerythrinus-unitaeniatus; Hypoxia; oxygen-tensions; rainbow-trout; salmo-gairdneri; Swimming; synbranchus-marmoratus  
  Résumé Clarias gariepinus is a facultative air-breathing catfish that exhibits changes in heart rate (f(H)) associated with air breaths (AB). A transient bradycardia prior to the AB is followed by sustained tachycardia during breath-hold. This study evaluated air-breathing and cardiac responses to sustained aerobic exercise in juveniles (total length similar to 20 cm), and how exercise influenced variations in f(H) associated with AB. In particular, it investigated the role of adrenergic and cholinergic control in cardiac responses, and effects of pharmacological abolition of this control on air-breathing responses. Sustained exercise at 15, 30 and 45 cm s(-1) in a swim tunnel caused significant increases in f(AB) and f(H), from approximately 5 breaths h(-1) and 60 heartbeats min(-1) at the lowest speed, to over 60 breaths h(-1) and 100 beats min(-1) at the highest, respectively. There was a progressive decline in the degree of variation in f(H), around each AB, as f(AB) increased with exercise intensity. Total autonomic blockade abolished all variation in fH during exercise, and around each AB, but f(AB) responses were the same as in untreated animals. Cardiac responses were exclusively due to modulation of inhibitory cholinergic tone, which varied from >100% at the lowest speed to <10% at the highest. Cholinergic blockade had no effect on f(AB) compared to untreated fish. Excitatory beta-adrenergic tone was approximately 20% and did not vary with swimming speed, but its blockade increased f(AB) at all speeds, compared to untreated animals. This reveals complex effects of autonomic control on air-breathing during exercise in C. gariepinus, which deserve further investigation. (C) 2016 Elsevier Inc. All rights reserved.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1095-6433 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1714  
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Auteur Iversen, N.K.; Dupont-Prinet, A.; Findorf, I.; McKenzie, D.J.; Wang, T. url  doi
openurl 
  Titre Autonomic regulation of the heart during digestion and aerobic swimming in the European sea bass (Dicentrarchus labrax) Type Article scientifique
  Année 2010 Publication Revue Abrégée Comp. Biochem. Physiol. A-Mol. Integr. Physiol.  
  Volume 156 Numéro 4 Pages 463-468  
  Mots-Clés Blood flow; Cardiovascular; Teleost; carassius-auratus; cardiac-performance; esox-lucius; fish; gadus-morhua; gastrointestinal blood-flow; metabolic-rate; metabolism; pressure control; rainbow-trout; salmo-gairdneri  
  Résumé The autonomic regulation of the heart was studied in European sea bass (Dicentrarchus labrax) during digestion and aerobic exercise by measuring cardiac output (Q), heart rate (f(H)), stroke volume (V(s)) and oxygen consumption (MO(2)) before and after pharmacological blockade by intraperitoneal injections of atropine and propranolol. The significant rise in MO(2) (134 +/- 14 to 174 +/- 14 mg kg(-1) h(-1)) 6 h after feeding (3% body mass) caused a significant tachycardia (47.7 +/- 10.9 to 72.6 +/- 7.2 beats min(-1)), but only a small elevation of Q. MO(2) of fasting fish increased progressively with swimming speed (0.7-2.1 BL s(-1)) causing a significant tachycardia (43 +/- 6 to 61 +/- 4 mL min(-1) kg(-1)) and increased Q but V(s) did not change. Inactive fish were characterized by a high vagal tone (98.3 +/- 21.7%), and the tachycardia during digestion and exercise was exclusively due to a reduction of vagal tone, while the adrenergic tone remained low during all conditions. Intrinsic f(H), revealed after double autonomic blockade, was not affected by digestion (71 +/- 4 and 70 +/- 6 min(-1), respectively), indicating that non-adrenergic, non-cholinergic (NANC) factors do not contribute to the tachycardia during digestion in sea bass. (C) 2010 Elsevier Inc. All rights reserved.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1095-6433 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 461  
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Auteur Jourdan-Pineau, H.; Dupont-Prinet, A.; Claireaux, G.; McKenzie, D.J. url  doi
openurl 
  Titre An Investigation of Metabolic Prioritization in the European Sea Bass, Dicentrarchus labrax Type Article scientifique
  Année 2010 Publication Revue Abrégée Physiol. Biochem. Zool.  
  Volume 83 Numéro 1 Pages 68-77  
  Mots-Clés Hypoxia; blood-flow; cardiac-performance; dynamic action; largemouth bass; oxygen-consumption; respiratory metabolism; salmo-gairdneri; swimming performance; trout oncorhynchus-mykiss  
  Résumé We investigated the ability of European sea bass (Dicentrarchus labrax) to respond simultaneously to the metabolic demands of specific dynamic action (SDA) and aerobic exercise and how this was influenced by moderate hypoxia (50% air saturation). At 3 h after feeding in normoxia at 20 degrees C, SDA raised the instantaneous oxygen uptake (Mo(2)) of sea bass by 47% +/- 18% (mean +/- SEM, N = 7) above their standard metabolic rate (SMR) when fasted. This metabolic load was sustained throughout an incremental exercise protocol until fatigue, with a 14% +/- 3% increase in their maximum aerobic metabolic rate (MMR) relative to their fasted rate. Their incremental critical swimming speed (U(crit)) did not differ between fasted and fed states. Thus, in normoxia, the bass were able to meet the combined oxygen demands of SDA and aerobic exercise. In hypoxia, the sea bass suffered a significant decline in MMR and U(crit) relative to their normoxic performance. The SDA response was similar to normoxia (84% +/- 24% above fasted SMR at 3 h after feeding), but although this load was sustained at low swimming speeds, it gradually disappeared as swimming speed increased. As a result, the hypoxic sea bass exhibited no difference in their fasted versus fed MMR. Hypoxic U(crit) did not, however, differ between fasted and fed states, indicating that the sea bass deferred their SDA to maintain exercise performance. The results demonstrate that, in normoxia, the sea bass possesses excess cardiorespiratory capacity beyond that required for maximal aerobic exercise. The excess capacity is lost when oxygen availability is limited in hypoxia, and, under these conditions, the sea bass prioritize exercise performance. Thus, environmental conditions (oxygen availability) had a significant effect on patterns of oxygen allocation in sea bass and revealed intrinsic prioritization among conflicting metabolic demands.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1522-2152 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 436  
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Auteur Riou, V.; Ndiaye, A.; Budzinski, H.; Dugue, R.; Le Menach, K.; Combes, Y.; Bossus, M.; Durand, J.D.; Charmantier, G.; Lorin-Nebel, C. url  doi
openurl 
  Titre Impact of environmental DDT concentrations on gill adaptation to increased salinity in the tilapia Sarotherodon melanotheron Type Article scientifique
  Année 2012 Publication Revue Abrégée Comp. Biochem. Physiol. C-Toxicol. Pharmacol.  
  Volume 156 Numéro 1 Pages 7-16  
  Mots-Clés DDTs; Na+/K+-ATPase; Osmoregulation; Rainbow trout; Teleost; cell responses; crucian carp; fish; gill; goldfish carassius-auratus; na-k-atpase; natural-populations; polychlorinated-biphenyls; salmo-gairdneri; water  
  Résumé Estuaries of tropical developing countries suffering from severe droughts induced by climate change are habitats to fish, which face drastic salinity variations and the contact with pollutants. The Western Africa tilapia Sarotherodon melanotheron is highly resistant to hypersalinity, but the effect of human-released xenobiotics on its adaptation is barely known. Controlled experiments were conducted to observe S. melanotheron gill adaptation to abrupt salinity variations in the presence of waterborne DDT, at concentrations detected in their natural habitat. The gills appeared as an important site of DDT conversion to DDD and/or depuration. A 12-days DDT exposure resulted in decreased gill epithelium thickness at all salinities (from fresh- to hypersaline-water), and the structure of gills from freshwater fish was particularly altered, relative to controls. No unbalance in tilapia blood osmolality was observed following DDT exposure, which however caused a decrease in branchial Na+-K+-ATPase (NKA) activity. Gill cellular NKA expression was reduced in salt-water, together with the expression of the CFTR chloride channel in hypersaline water. Although S. melanotheron seems very resistant (especially in seawater) to short-term waterborne DDT contamination, the resulting alterations of the gill tissue, cells and enzymes might affect longer term respiration, toxicant depuration and/or osmoregulation in highly fluctuating salinities. (C) 2012 Elsevier Inc. All rights reserved.  
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  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1532-0456 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 649  
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