Calcium Stored in the Sarcoplasmic Reticulum Acts as a Safety Mechanism in Fish Heart

Cardiac contraction is mediated by a transient increase in calcium ([Ca]) inside the cytoplasm. In mammalian cardiomyocytes most of the calcium for cardiac contraction is from the calcium stored in the sarcoplasmic reticulum (SR). In fish cardiomyocytes, the relative contribution of calcium coming from the extracellular space versus SR is not clear. This study addresses this point. Trout ventricular myocytes were enzymatically isolated. Calcium...