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Updated: Sep 27, 2026

Analysis of the Mitochondrial Density and Longitudinal Distribution in Rat Live-Skeletal Muscle Fibers by Confocal Microscopy
Published on: December 1, 2023
Mitochondrial K(ATP) channels and sarcoplasmic reticulum influence cardiac force development under anoxia in the
Tyson J MacCormack1, Jason R Treberg, Vera M F Almeida-Val
1Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, A1C 5S7, Newfoundland, Canada.
Abstract:
The contribution of alterations in mitochondrial K(ATP) channel activity and the sarcoplasmic reticulum (SR) to anaerobic cardiac function in the anoxia tolerant armored catfish Liposarcus pardalis were assessed. K(ATP) channels contribute to hypoxic cardioprotection in mammals, but little is known of their action in more hypoxia tolerant animals. Anoxia resulted in a decrease in force in isometrically contracting ventricle strips to approximately 40% of the pre-anoxic level. This was maintained for at least 2 h. Upon reoxygenation, hearts recovered to the same level as control preparations. Treatment with 5-hydroxydecanoic acid (5HD), a specific mitochondrial K(ATP) blocker significantly increased force in preparations during anoxia and caused hypercontracture at reoxygenation. Ryanodine, a specific inhibitor of SR function, significantly increased force loss in ventricle preparations under anoxia. Results show that mitochondrial K(ATP) channel activity and SR function are important in anaerobic and post-anaerobic contractility in armored catfish heart.
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