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Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia

Citation

Ekstrom, A and Brijs, J and Clark, TD and Grans, A and Jutfelt, F and Sandblom, E, Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia, American Journal of Physiology, 311 pp. 440-449. ISSN 0002-9513 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 the American Physiological Society

DOI: doi:10.1152/ajpregu.00530.2015

Abstract

Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring venous oxygen tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 510C above ambient (24C at the time of experiments). While CTmax was 2.2C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.34.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac oxygen supply appears critical to elevate stroke volume at high temperatures, oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax. Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial oxygen limitations, and likely involves limiting factors on multiple organizational levels.

Item Details

Item Type:Refereed Article
Keywords:climate change, thermal distribution
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal Physiological Ecology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Coastal and Estuarine Flora, Fauna and Biodiversity
Author:Clark, TD (Dr Timothy Clark)
ID Code:112356
Year Published:2016
Web of Science® Times Cited:4
Deposited By:Office of the DVC-R
Deposited On:2016-11-04
Last Modified:2017-06-20
Downloads:0

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