Tail integral and end/peak ratio during repetitive stimulation. (A) Representative mag-fluo-4 fluorescence trace elicited during a single stimulus train (500 ms at 50 Hz) highlighting analysis of tail integral (left, gray shaded area) and end/peak ratio (right). (B) Representative superimposed mag-fluo-4 (ΔF/F₀) traces during the 1st (left) and 40th (right) stimulus train in FDB fibers isolated from WT and CASQ1-null mice. (C and D) Ca²⁺ transient tail integral (C) and end/peak ratio (D) analyses in FDB fibers from WT and CASQ1-null mice. Data are shown as mean ± SEM; *, P < 0.05. Numbers in parentheses (n) indicate the number of FDB fibers analyzed. Number of mice: n = 4 WT; n = 5 CASQ1-null. AUC, area under the curve.