Cardiophysiological responses of the air-breathing Alaska blackfish to cold acclimation and chronic hypoxic submergence at 5°C.

ABSTRACT: The Alaska blackfish (Dallia pectoralis) remains active at cold temperatures when experiencing aquatic hypoxia without air access. To discern the cardiophysiological adjustments that permit this behaviour, we quantified the effect of acclimation from 15°C to 5°C in normoxia (15N and 5N fish), as well as chronic hypoxic submergence (6-8 weeks; ∼6.3-8.4 kPa; no air access) at 5°C (5H fish), on in vivo and spontaneous heart rate (f_H), electrocardiogram, ventricular action potential (AP) shape and duration (APD), the background inward rectifier (I_K1) and rapid delayed rectifier (I_Kr) K⁺ currents and ventricular gene expression of proteins involved in excitation-contraction coupling. In vivo f_H was

SUBMITTER: Stecyk JAW 

PROVIDER: S-EPMC7687868 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature