Transcript expression of inward rectifier potassium channels of Kir2 subfamily in Arctic marine and freshwater fish species

• Published in: Journal of Comparative Physiology B
• Main Authors: Hassinen, M., Korajoki, H., Abramochkin, D., Krivosheya, P., Vornanen, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Verlag 2019
• Subjects: FISH HEART; INWARD RECTIFIER POTASSIUM CHANNELS; KIR2 PARALOGUES; RT-QPCR; THERMAL ACCLIMATION; FRESH WATER; INWARDLY RECTIFYING POTASSIUM CHANNEL; ANIMAL; AQUATIC SPECIES; CLASSIFICATION; ECOSYSTEM; FISH; GENE EXPRESSION REGULATION; GENETICS; HEART ATRIUM; HEART VENTRICLE; METABOLISM; MOLECULAR CLONING; PHYSIOLOGY; SPECIES DIFFERENCE; TEMPERATURE; ANIMALS; AQUATIC ORGANISMS; CLONING; MOLECULAR; FISHES; HEART ATRIA; HEART VENTRICLES; POTASSIUM CHANNELS; INWARDLY RECTIFYING; SPECIES SPECIFICITY; Arctic; Arctic Ocean; Navaga; Boreogadus saida; Burbot; Esox lucius; Lota lota; polar cod; Salvelinus alpinus; lota
• Online Access: http://elar.urfu.ru/handle/10995/90489; https://link.springer.com/content/pdf/10.1007/s00360-019-01241-9.pdf; http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85074697998; https://doi.org/10.1007/s00360-019-01241-9

Inward rectifier K+ (Kir2) channels are critical for electrical excitability of cardiac myocytes. Here, we examine expression of Kir2 channels in the heart of three Gadiformes species, polar cod (Boreogadus saida) and navaga (Eleginus nawaga) of the Arctic Ocean and burbot (Lota lota) of the temperate lakes to find out the role of Kir2 channels in cardiac adaptation to cold. Five boreal freshwater species: brown trout (Salmo trutta fario), arctic char (Salvelinus alpinus), roach (Rutilus rutilus), perch (Perca fluviatilis) and pike (Esox lucius), and zebrafish (Danio rerio), were included for comparison. Transcript expression of genes encoding Kir2.1a, − 2.1b, − 2.2a, − 2.2b and − 2.4 was studied from atrium and ventricle of thermally acclimated or acclimatized fish by quantitative PCR. Kir2 composition in the polar cod was more diverse than in other species in that all Kir2 isoforms were relatively highly expressed. Kir2 composition of navaga and burbot differed from that of the polar cod as well as from those of other species. The relative expression of Kir2.2 transcripts, especially Kir2.2b, was higher in both atrium and ventricle of navaga and burbot (56–89% from the total Kir2 pool) than in other species (0.1–11%). Thermal acclimation induced only small changes in cardiac Kir2 transcript expression in Gadiformes species. However, Kir2.2b transcripts were upregulated in cold-acclimated navaga and burbot hearts. All in all, the cardiac Kir2 composition seems to be dependent on both phylogenetic position and thermal preference of the fish. © 2019, The Author(s). Academy of Finland: 14955 Open access funding provided by University of Eastern Finland (UEF) including Kuopio University Hospital. The authors thank Anita Kervinen for her assistance with the fish. This work was supported by the Academy of Finland (grant number 14955).