Figure 4.

Effects of elevated SR Ca²⁺ content on Ca²⁺-wave propagation by pausing pacing for 10 s when [Ca²⁺]_o was increased from 1 mM to 10 mM and by increasing SR uptake rate P_up by 70%. (A i and A ii) Line-scan images of spatial patterns of [Ca²⁺]_i transients produced by pausing voltage-clamp pulse and increasing P_up, respectively. (B, B i, and B ii) Traces of [Ca²⁺]_i (upper) and [Ca²⁺]_SR (lower) recorded from peripheral (black; see online color figure) and central (red; see online color figure) regions of the cell before (B) and after (B i and B ii) elevating the SR Ca²⁺ content. (Insets A–D) Expanded plots of the time traces for the time periods marked by the brackets with asterisks shown in B i and B ii.