Electrically evoked Ca²⁺ transients in intact FDB fibers during acute exposure to BTP2. (A–C) Representative mag-fluo-4 traces during 180 s of continuous electrically evoked twitch stimulation (0.5 Hz), starting with a 60-s perfusion with control Ringer’s solution followed by 120 s application of DMSO control (A), 10 µM BTP2 (B), or 20 µM BTP2 (C) in Ringer’s solution. (D) Average (± SEM) peak ΔF/F₀ throughout the 180 s of continuous stimulation. Inset: Representative traces of electrically evoked mag-fluo-4 transients before (0 min) and at the end (2 min) of DMSO or BTP2 exposure. n = 18–36 cells from three to five mice; one-way ANOVA with Tukey post hoc test.