Responses of Action Potential and K+Currents to Temperature Acclimation in Fish Hearts: Phylogeny or Thermal Preferences?
- 1 September 2009
- journal article
- research article
- Published by University of Chicago Press in Physiological and Biochemical Zoology
- Vol. 82 (5), 468-482
- https://doi.org/10.1086/590223
Abstract
Electrical activity of the heart is assumed to be one of the key factors that set thermal tolerance limits for ectothermic vertebrates. Therefore, we hypothesized that in thermal acclimation--the duration of cardiac action potential and the repolarizing K+ currents that regulate action potential duration (APD)--the rapid component of the delayed rectifier K+ current (I(Kr)) and the inward rectifier K+ current (I(K1)) are more plastic in eurythermal than in stenothermal fish species. The hypothesis was tested in six freshwater teleosts representing four different fish orders (Cadiformes, Cypriniformes, Perciformes, Salmoniformes) acclimated at +4 degrees C (cold acclimation) or +18 degrees C (warm acclimation). In cold acclimation, a compensatory shortening of APD occurred in all species regardless of thermal tolerances, life styles, or phylogenies of the fish, suggesting that this response is a common characteristic of the teleost heart. The strength of the response did not, however, obey simple eurythermy-stenothermy gradation but differed among the phylogenetic groups. Salmoniformes fish showed the greatest acclimation capacity of cardiac electrical activity, whereas the weakest response appeared in the perch (Perciformes) heart. The underlying ionic mechanisms were also partly phylogeny dependent. Modification of the I(Kr) current was al- most ubiquitously involved in acclimation response of fish cardiac myocytes to temperature, while the ability to change the I(K1) current under chronic thermal stress was absent or showed inverse compensation in Salmoniformes species. Thus, in Salmoniformes fish, the thermal plasticity of APD is strongly based on I(Kr), while other fish groups rely on both I(Kr) and I(K1).Keywords
This publication has 39 references indexed in Scilit:
- Significance of Na+ current in the excitability of atrial and ventricular myocardium of the fish heartJournal Of Experimental Biology, 2006
- Temperature acclimation modifies Na+ current in fish cardiac myocytesJournal Of Experimental Biology, 2004
- Sonic Tracking of Burbot in Lake Opeongo, OntarioTransactions of the American Fisheries Society, 1995
- Environmental influences on cardiovascular variables in rainbow trout, Oncorhynchus mykiss (Walbaum)Journal of Fish Biology, 1992
- Effect of acute and chronic temperature transition on enzymes of cardiac metabolism in white perch (Morone americana), yellow perch (Perca flavescens), and smallmouth bass (Micropterus dolomieui)Canadian Journal of Zoology, 1991
- The cardiac excitation-contraction cyclePharmacology & Therapeutics, 1982
- Lethal and ‘disturbing’ temperatures in some fish species from lakes with normal and artificially elevated temperatureJournal of Fish Biology, 1973
- Isoenzymes and Short-term Temperature Compensation in Poikilotherms: Activation of Lactate Dehydrogenase Isoenzymes by Temperature DecreasesNature, 1969
- Thermal Resistance of Pike (Esox lucius L.), Muskellunge (E. masquinongy Mitchill), and their F1 HybridJournal of the Fisheries Research Board of Canada, 1964
- Upper Lethal Temperatures of Some British Columbia Freshwater FishesJournal of the Fisheries Research Board of Canada, 1953