Acute and chronic cold exposure differentially affect cardiac control, but not cardiorespiratory function, in resting Atlantic salmon (S almo salar ).

Autor: Porter ES; Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada., Clow KA; Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada., Sandrelli RM; Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada., Gamperl AK; Dept. of Ocean Sciences, Memorial University of Newfoundland and Labrador, St. John's, NL, A1C 5S7, Canada.
Jazyk: angličtina
Zdroj: Current research in physiology [Curr Res Physiol] 2022 Mar 17; Vol. 5, pp. 158-170. Date of Electronic Publication: 2022 Mar 17 (Print Publication: 2022).
DOI: 10.1016/j.crphys.2022.03.002
Abstrakt: No studies have examined the effects of cold temperatures (∼0-1 °C) on in vivo cardiac function and control, and metabolism, in salmonids. Thus, we examined: 1) how acclimation to 8 °C vs. acclimation (>3 weeks) or acute exposure (8-1 °C at 1 °C h -1 ) to 1 °C influenced cardiorespiratory parameters in resting Atlantic salmon; and 2) if/how the control of cardiac function was affected. Oxygen consumption ( M ˙ O 2 ) and cardiac function [i.e., heart rate ( f H ) and cardiac output ( Q ˙ ) ] were 50% lower in the acutely cooled and 1 o C-acclimated salmon as compared to 8 °C fish, whereas stroke volume (V S ) was unchanged. Intrinsic f H was not affected by whether the fish were acutely exposed or acclimated to 1 °C (values ∼51, 24 and 21 beats min -1 in 8 and 1 °C-acclimated fish, and 8-1 °C fish, respectively), and in all groups f H was primarily under adrenergic control/tone (cholinergic tone 13-18%; adrenergic tone 37-70%). However, β-adrenergic blockade resulted in a 50% increase in V S in the 1 o C-acclimated group, and this was surprising as circulating catecholamine levels were ∼1-3 nM in all groups. Overall, the data suggest that this species has a limited capacity to acclimate to temperatures approaching 0 °C. However, we cannot exclude the possibility that cardiac and metabolic responses are evoked when salmon are cooled to ∼ 0-1 °C, and that this prevented further declines in these parameters (i.e., they 'reset' quickly). Our data also provide further evidence that V S is temperature insensitive, and strongly suggest that changes in adrenoreceptor mediated control of venous pressure/capacitance occur when salmon are acclimated to 1 °C.
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Gamperl reports financial support was provided by the 10.13039/501100000038Natural Sciences and Engineering Research Council of Canada.
(© 2022 The Authors.)
Databáze: MEDLINE
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