Warm-induced bradycardia and cold-induced tachycardia: mechanisms of cardiac and ventilatory control in a warm-acclimated Antarctic fish
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Colleges, School and Institutes
While many Antarctic organisms possess only limited ability to respond to environmental temperature change, there is now substantial evidence to confirm that the notothenioid fish, Pagothenia borchgrevinki, has retained some thermal flexibility and can successfully acclimate to a 5 degrees C increase in temperature. Previous research demonstrated that after acclimation to 4 degrees C, resting cardiac output in this species was thermally independent, while cold-adapted fish demonstrated thermal dependence of cardiac output. Here, we extend this research into cardiovascular plasticity and report the following: (1) The mechanisms responsible for the thermal independence of cardiac output in warm-acclimated (4 degrees C, for 4 weeks) fish include a combination of warm-induced bradycardia and cold-induced tachycardia bouts. (2) These acute responses are under cholinergic control. (3) Changes to the thermal sensitivity of heart rate and ventilation rate result in concomitant changes to cardio-respiratory coupling in warm-acclimated fish.
|Number of pages||9|
|Publication status||Published - 1 Mar 2011|
- Thermal acclimation, Cardio-respiratory coupling, Cardiovascular system, Pagothenia borchgrevinki, Notothenioid, Antarctic fish