Fig. 6. Variable characteristics of spontaneous Ca²⁺ signals in RyR3-expressing cells. A and B illustrate the considerable variability of spontaneous Ca²⁺ signals in two RyR3-expressing cells. The traces in Aa and Ba depict the Ca²⁺ changes in the regions along the line scan images marked by the arrows. Panel C depicts the effect of 100 µM ryanodine treatment on spontaneous Ca²⁺-release activity in a single RyR3-expressing cell.