Figure 11 – Inhibition of CSQ Ca²⁺ buffering effects promotes SCRs in all CRUs.

A) Rate threshold for local SCRs of surface (left), inner coupled (middle) and inner uncoupled (right) CRUs in sparse, intermediate and densely tubulated cells with the impact of altered CSQ Ca²⁺ buffering effects greatest in inner coupled/uncoupled CRUs of cells with dense and intermediate tubules. B) Cytosolic Ca²⁺ concentration of surface (left), inner coupled (middle) and inner uncoupled (right) CRUs from cells with dense (i), intermediate (ii), and sparse (iii) tubules following pacing at 3 Hz showing observed SCRs with varying fraction of CSQ Ca²⁺ buffering effects.