||Ollivier Helene1, Marchant James2, Le Bayon Nicolas2, Servili Arianna2, Claireaux Guy2
||1 : Univ Bretagne Occidentale, ORPHY, Brest, France.
2 : Ctr Ifremer Brest, LEMAR, Unite PFOM ARN, Plouzane, France.
||Journal Of Comparative Physiology B-Biochemical Systemic And Environmental Physiology (0174-1578) (Springer Heidelberg), 2015-10 , Vol. 185 , N. 7 , P. 755-765
|WOS© Times Cited
||Sea bass, Myocyte populations, Calcium signaling, Cardiac plasticity, Inter-individual variability
||Climate change challenges the capacity of fishes to thrive in their habitat. However, through phenotypic diversity, they demonstrate remarkable resilience to deteriorating conditions. In fish populations, inter-individual variation in a number of fitness-determining physiological traits, including cardiac performance, is classically observed. Information about the cellular bases of inter-individual variability in cardiac performance is scarce including the possible contribution of excitation-contraction (EC) coupling. This study aimed at providing insight into EC coupling-related Ca2+ response and thermal plasticity in the European sea bass (Dicentrarchus labrax). A cell population approach was used to lay the methodological basis for identifying the cellular determinants of cardiac performance. Fish were acclimated at 12 and 22 A degrees C and changes in intracellular calcium concentration ([Ca2+](i)) following KCl stimulation were measured using Fura-2, at 12 or 22 A degrees C-test. The increase in [Ca2+](i) resulted primarily from extracellular Ca2+ entry but sarcoplasmic reticulum stores were also shown to be involved. As previously reported in sea bass, a modest effect of adrenaline was observed. Moreover, although the response appeared relatively insensitive to an acute temperature change, a difference in Ca2+ response was observed between 12- and 22 A degrees C-acclimated fish. In particular, a greater increase in [Ca2+](i) at a high level of adrenaline was observed in 22 A degrees C-acclimated fish that may be related to an improved efficiency of adrenaline under these conditions. In conclusion, this method allows a rapid screening of cellular characteristics. It represents a promising tool to identify the cellular determinants of inter-individual variability in fishes' capacity for environmental adaptation.
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