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Campo DC | Valor | Idioma |
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dc.contributor.author | Scott, Graham R. | - |
dc.contributor.author | Wood, Chris M. | - |
dc.contributor.author | Sloman, Katherine A. | - |
dc.contributor.author | Iftikar, Fathima I. | - |
dc.contributor.author | Boeck, Gudrun de | - |
dc.contributor.author | Val, Vera Maria Fonseca Almeida e | - |
dc.contributor.author | Val, Adalberto Luis | - |
dc.date.accessioned | 2020-06-15T22:02:05Z | - |
dc.date.available | 2020-06-15T22:02:05Z | - |
dc.date.issued | 2008 | - |
dc.identifier.uri | https://repositorio.inpa.gov.br/handle/1/18543 | - |
dc.description.abstract | This study determined the respiratory responses to progressive hypoxia in oscar, an extremely hypoxia-tolerant Amazonian cichlid. Oscar depressed oxygen consumption rates (over(M, ̇)O2), beginning at a critical O2 tension (Pcrit) of 46 Torr, to only 14% of normoxic rates at 10 Torr. Total ventilation (over(V, ̇)w) increased up to 4-fold, entirely due to a rise in ventilatory stroke volume (no change in ventilatory frequency), and water convection requirement (over(V, ̇)w / over(M, ̇)O2) increased substantially (up to 15-fold). Gill O2 extraction fell steadily, from 60% down to 40%. Although O2 transfer factor (an index of gill O2 diffusion capacity) increased transiently in moderate hypoxia, it decreased at 10 Torr, which may have caused the increased expired-arterial PO2 difference. Venous PO2 was always very low (≤7 Torr). Anaerobic metabolism made a significant contribution to ATP supply, indicated by a 3-fold increase in plasma lactate that resulted in an uncompensated metabolic acidosis. Respiration of isolated gill cells was not inhibited until below 5 Torr; because gill water PO2 always exceeded this value, hypoxic ion flux arrest in oscars [Wood et al., Am. J. Physiol. Reg. Integr. Comp. Physiol. 292, R2048-R2058, 2007] is probably not caused by O2 limitation in ionocytes. We conclude that metabolic depression and tolerance of anaerobic bi-products, rather than a superior capacity for O2 supply, allow oscar to thrive in extreme hypoxia in the Amazon. © 2008 Elsevier B.V. All rights reserved. | en |
dc.language.iso | en | pt_BR |
dc.relation.ispartof | Volume 162, Número 2, Pags. 109-116 | pt_BR |
dc.rights | Restrito | * |
dc.subject | Animals Experiment | en |
dc.subject | Breathing | en |
dc.subject | Cell Respiration | en |
dc.subject | Cichlid | en |
dc.subject | Controlled Study | en |
dc.subject | Fish | en |
dc.subject | Gas Exchange | en |
dc.subject | Gill | en |
dc.subject | Hypoxia | en |
dc.subject | Nonhuman | en |
dc.subject | Oxygen Consumption | en |
dc.subject | Priority Journal | en |
dc.subject | Adaptation, Physiological | en |
dc.subject | Anaerobic Threshold | en |
dc.subject | Animal | en |
dc.subject | Anoxia | en |
dc.subject | Cell Respiration | en |
dc.subject | Cichlids | en |
dc.subject | Energy Metabolism | en |
dc.subject | Gills | en |
dc.subject | Lactic Acid | en |
dc.subject | Oxygen Consumption | en |
dc.subject | Respiratory Mechanics | en |
dc.title | Respiratory responses to progressive hypoxia in the Amazonian oscar, Astronotus ocellatus | en |
dc.type | Artigo | pt_BR |
dc.identifier.doi | 10.1016/j.resp.2008.05.001 | - |
dc.publisher.journal | Respiratory Physiology and Neurobiology | pt_BR |
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