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Auteur Iversen, N.K.; McKenzie, D.J.; Malte, H.; Wang, T.
Titre Reflex bradycardia does not influence oxygen consumption during hypoxia in the European eel (Anguilla anguilla) Type Article scientifique
Année 2010 Publication Revue Abrégée J. Comp. Physiol. B-Biochem. Syst. Environ. Physiol.
Volume 180 Numéro 4 Pages 495-502
Mots-Clés Anguilla anguilla; Cardiac output; Critical oxygen tension; Hypoxic bradycardia; Oxygen; Teleost; atlantic cod; cardiac vagotomy; circulation; consumption; dogfish scyliorhinus-canicula; fish; heart-rate; rainbow-trout; responses; temperature; tolerance
Résumé Most teleost fish reduce heart rate when exposed to acute hypoxia. This hypoxic bradycardia has been characterised for many fish species, but it remains uncertain whether this reflex contributes to the maintenance of oxygen uptake in hypoxia. Here we describe the effects of inhibiting the bradycardia on oxygen consumption (MO(2)), standard metabolic rate (SMR) and the critical oxygen partial pressure for regulation of SMR in hypoxia (Pcrit) in European eels Anguilla anguilla (mean +/- A SEM mass 528 +/- A 36 g; n = 14). Eels were instrumented with a Transonic flow probe around the ventral aorta to measure cardiac output (Q) and heart rate (f (H)). MO(2) was then measured by intermittent closed respirometry during sequential exposure to various levels of increasing hypoxia, to determine Pcrit. Each fish was studied before and after abolition of reflex bradycardia by intraperitoneal injection of the muscarinic antagonist atropine (5 mg kg(-1)). In the untreated eels, f (H) fell from 39.0 +/- A 4.3 min(-1) in normoxia to 14.8 +/- A 5.2 min(-1) at the deepest level of hypoxia (2 kPa), and this was associated with a decline in Q, from 7.5 +/- A 0.8 mL min(-1) kg(-1) to 3.3 +/- A 0.7 mL min(-1) kg(-1) in normoxia versus deepest hypoxia, respectively. Atropine had no effect on SMR, which was 16.0 +/- A 1.8 mu mol O(2) kg(-1) min(-1) in control versus 16.8 +/- A 0.8 mu mol O(2) kg(-1) min(-1) following treatment with atropine. Atropine also had no significant effect on normoxic f (H) or Q in the eel, but completely abolished the bradycardia and associated decline in Q during progressive hypoxia. This pharmacological inhibition of the cardiac responses to hypoxia was, however, without affect on Pcrit, which was 11.7 +/- A 1.3 versus 12.5 +/- A 1.5 kPa in control versus atropinised eels, respectively. These results indicate, therefore, that reflex bradycardia does not contribute to maintenance of MO(2) and regulation of SMR by the European eel in hypoxia.
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Auteur Jorgensen, C.; Peck, M.A.; Antognarelli, F.; Azzurro, E.; Burrows, M.T.; Cheung, W.W.L.; Cucco, A.; Holt, R.E.; Huebert, K.B.; Marras, S.; McKenzie, D.; Metcalfe, J.; Perez-Ruzafa, A.; Sinerchia, M.; Steffensen, J.F.; Teal, L.R.; Domenici, P.
Titre Conservation physiology of marine fishes: advancing the predictive capacity of models Type Article scientifique
Année 2012 Publication Revue Abrégée Biol. Lett.
Volume 8 Numéro 6 Pages 900-903
Mots-Clés atlantic cod; body-mass; climate-change; climate effects; conservation physiology; gadus-morhua; metabolic scope; modelling; ocean; species distribution; temperature
Résumé At the end of May, 17 scientists involved in an EU COST Action on Conservation Physiology of Marine Fishes met in Oristano, Sardinia, to discuss how physiology can be better used in modelling tools to aid in management of marine ecosystems. Current modelling approaches incorporate physiology to different extents, ranging from no explicit consideration to detailed physiological mechanisms, and across scales from a single fish to global fishery resources. Biologists from different sub-disciplines are collaborating to rise to the challenge of projecting future changes in distribution and productivity, assessing risks for local populations, or predicting and mitigating the spread of invasive species.
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ISSN 1744-9561 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1432
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