Contractile performance of the Alaska blackfish (Dallia pectoralis) ventricle: Assessment of the effects of temperature, pacing frequency, the role of the sarcoplasmic reticulum in contraction and adrenergic stimulation.

ABSTRACT: The air-breathing Alaska blackfish (Dallia pectoralis) experiences aquatic hypoxia, but restricted air-access in winter due to ice-cover. To lend insight into its overwintering strategy, we examined the effects of thermal acclimation (15 °C vs. 5 °C), acute temperature change (to 10 °C), increased pacing frequency, inhibition of sarcoplasmic reticulum (SR) Ca²⁺ release and uptake and adrenaline (1000 nmol l^-1) on the contractile performance of isometrically-contracting, electrically-paced ventricular strips. At routine pacing frequencies, maximal developed force (F_max) was equivalent at 5 °C (2.1 ± 0.2 mN mm^-2) and 15 °C (2.2 ± 0.3 mN mm^-2), whereas contraction durations were 2.2- to 2.4-times longer and contraction rates 2.4- to 3.5-t

SUBMITTER: Kubly KL 

PROVIDER: S-EPMC6824994 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature