Figure 5. IP₃ evokes a divergent response in CaSpF in WT and TG permeabilized myocytes.

A, representative line‐scan images of Ca²⁺ events in permeabilized cardiomyocytes in control conditions and in the presence of 10 μM IP₃‐salt and/or 2 μM 2‐APB, 3 μM XeC in WT and TG. After permeabilization and plating, each cell was scanned before and 2–4 min after pharmacological intervention. B, representative line‐scan images with the corresponding fluorescence profiles of de‐skewed caffeine (20 mM)‐induced Ca²⁺ transients under control conditions in WT and TG permeabilized myocytes. C, Ca²⁺ spark frequency (Ca²⁺ sparks (100 μm)⁻¹ s⁻¹) and SR‐Ca²⁺ content (ΔF/F ₀) in control conditions in WT and TG cells (^*** P < 0.001 vs. WT; n = 25 each, N = 8 each; Student's t test). D, normalized Ca²⁺ spark frequencies (norm.) and SR‐Ca²⁺ content (20 mM caffeine, ΔF/F ₀) after Ca²⁺ event occurrence assessment in control conditions and in the presence of IP₃‐salt and/or 2‐APB, XeC in WT (n of groups 1–4 = 25, 22, 20, 16; N of groups 1–4 = 8, 8, 3, 3) and TG myocytes (n of groups 1–4 = 25, 13, 11, 10; N of groups 1–4 = 8, 3, 3, 3; ^* P < 0.05, ^** P < 0.01 vs. control; ^† P < 0.05, ^†† P < 0.01 vs. IP₃; ANOVA followed by Dunnett's test).