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Exploring nature's natural knockouts: cardiorespiratory performance of Antarctic fishes during acute warming.

TitleExploring nature's natural knockouts: cardiorespiratory performance of Antarctic fishes during acute warming.
Publication TypeJournal Article
Year of Publication2018
AuthorsJoyce, W, Egginton, S, Farrell, AP, Crockett, EL, O'Brien, KM, Axelsson, M
JournalJ Exp Biol
Date Published2018 Jul 02
ISSN1477-9145
Abstract

We tested the hypothesis that Blackfin icefish (), one of the six species in the family Channichthyidae (the icefishes) that do not express haemoglobin and myoglobin, lack regulatory cardiovascular flexibility during acute warming and activity. The experimental protocols were designed to optimize the surgical protocol and minimize stress. First, minimally invasive heart rate () measurements were made during a thermal ramp until cardiac failure in and compared with the closely related red-blooded Black rockcod (). Then, integrative cardiovascular adjustments were more extensively studied using flow probes and intravascular catheters in during acute warming (from 0 to 8°C) at rest and after imposed activity. had a lower routine than (9 min 14 min) and a lower peak during acute warming (38 min 55 min) with a similar cardiac breakpoint temperature (13 and 14°C, respectively). Routine cardiac output () for at ∼0°C was much lower (26.6 ml min kg) than previously reported, likely because fish in the present study had a low (12 min) indicative of a high routine vagal tone and low stress. increased oxygen consumption during acute warming and with activity. Correspondingly, increased considerably (maximally 86.3 ml min kg), as did vascular conductance (five-fold). Thus, unlike earlier suggestions, these data provide convincing evidence that icefish can mount a well-developed cardiovascular regulation of heart rate, cardiac output and vascular conductance, and this regulatory capacity provides flexibility during acute warming.

DOI10.1242/jeb.183160
Alternate JournalJ. Exp. Biol.
PubMed ID29967219
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