In vitro cardiac performance in triploid brown trout at two acclimation temperatures |
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Authors: | C. Mercier,M. Axelsson,,N. Imbert,,G. Claireaux,,C. Lefranç ois,,J. Altimiras,A. P. Farrell |
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Affiliation: | LBEM, Institut de la Mer et du Littoral, Avenue Lazaret, 17 000, La Rochelle, France;CREMA-L'Houmeau, Place du Séeminaire, BP5, L'Houmeau 17137, France;Department of Zoology, University of Göteborg, Box 463, 40530 Göteborg, Sweden;Department of Biological Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada |
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Abstract: | The maximum values for heart rate ( f H), stroke volume ( V H), cardiac output ( Q ) and myocardial power output, measured in vitro with a perfused heart preparation, as well as the isometric force-frequency relationship for atrial and ventricular muscle strips, in triploid brown trout Salmo trutta were all comparable with established information for diploid rainbow trout Oncorhynchus mykiss . Therefore, it was concluded that triploidy is not associated with a major deficiency in maximum cardiac performance. However, a heightened sensitivity to ryanodine was discovered, which indicated an enhanced role for the sarcoplasmic reticulum in excitation-contraction coupling in these triploid fish. It is suspected that the enhanced role of the ryanodine receptor may be a cellular compensation related to larger cardiac myocytes. It was also clearly established that there was a plateau in maximum cardiac performance between 14 and 18° C and this plateau might be a contributing factor to the reduced factorial aerobic scope and increased fish mortality observed at 18° C. |
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Keywords: | triploidy temperature cardiac power output heart rate cardiac output myocytes contractility adrenaline ryanodine |
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