Passive Ca2+ overload in H9c2 cardiac myoblasts: Assessment of cellular damage and cytosolic Ca2+ transients

► Cells deprived of serum can tolerate certain Ca2+-overload without cell damage. ► Cells in the presence of serum can tolerate 10 mM Ca2+ for at least 48 h. ► Cell damage after Ca2+ overload similar to control cells when serum is present. ► Tolerance to high Ca2+ was linked to reduced sarcoplasmic reticulum Ca2+ overload.