title: Calcium response of KCl-excited populations of ventricular myocytes from the European sea bass (Dicentrarchus labrax): a promising approach to integrate cell-to-cell heterogeneity in studying the cellular basis of fish cardiac performance.
abstract: 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 Ca(2+) 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 °C and changes in intracellular calcium concentration ([Ca(2+)]i) following KCl stimulation were measured using Fura-2, at 12 or 22 °C-test. The increase in [Ca(2+)]i resulted primarily from extracellular Ca(2+) 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 Ca(2+) response was observed between 12- and 22 °C-acclimated fish. In particular, a greater increase in [Ca(2+)]i at a high level of adrenaline was observed in 22 °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.
authors.affiliation: ORPHY, Université de Bretagne Occidentale, Brest, France. Helene.Ollivier@univ-brest.fr.
authors.forename: Hélène
authors.initials: H
authors.lastname: Ollivier
authors.affiliation: Unité PFOM-ARN, LEMAR, Centre Ifremer de Brest, Plouzané, France.
authors.forename: James
authors.initials: J
authors.lastname: Marchant
authors.affiliation: Unité PFOM-ARN, LEMAR, Centre Ifremer de Brest, Plouzané, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Le Bayon
authors.affiliation: Unité PFOM-ARN, LEMAR, Centre Ifremer de Brest, Plouzané, France.
authors.forename: Arianna
authors.initials: A
authors.lastname: Servili
authors.affiliation: Unité PFOM-ARN, LEMAR, Centre Ifremer de Brest, Plouzané, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Claireaux
mesh_terms: D000064:Acclimatization; D000818:Animals; D001492:Bass / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D056966:Excitation Contraction Coupling / Q000187:drug effects*; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D011189:Potassium Chloride; D002118:Calcium; D004837:Epinephrine
keywords: Calcium signaling; Cardiac plasticity; Inter-individual variability; Myocyte populations; Sea bass