Fig. 2

Modulation of SR Ca²⁺ uptake at resting in field stimulated myocytes. A Post-rest potentiation (PRP) protocol in Fluo4 field stimulated (2 Hz) myocytes: steady state Ca²⁺ transients (ssCa_T) and superimposed first post-rest (pr) Ca²⁺ transients (prCa_T) following increasing resting pause (1-5-10-20 s) are reported in healthy and STZ myocytes, with or w/o 1 μM compound 8. Traces were normalized to own diastolic Ca²⁺ level (dotted line). B Analysis of the prCa_T amplitude normalized to the amplitude of the pre-pause ssCa_T and its pause dependency; healthy N = 3 (n = 34 w/o compound 8, n = 38 with compound 8), STZ N = 3 (n = 31 w/o compound 8, n = 32 with compound 8). *p < 0.05 for the interaction factor in RM two-way ANOVA, indicating a different steepness of curves. C Statistics for Ca_rest, ssCa_T amplitude and ssCa_T half decay time (t_1/2); healthy N = 3 (n = 28 w/o compound 8, n = 35 with compound 8), STZ N = 3 (n = 24 w/o compound 8, n = 28 with compound 8). *p < 0.05 (one-way ANOVA plus post-hoc Tukey’s multiple comparison). D Caffeine-induced Ca_T (Ca_SR) in field stimulated healthy and STZ myocytes with or w/o 1 μM compound 8 following 0.5 s (in grey) or 20 s (in black) resting pause. E Statistics for CaSR_20s/CaSR_0.5 s; healthy N = 3 (n = 28 w/o compound 8, n = 35 with compound 8), STZ N = 3 (n = 23 w/o compound 8, n = 28 with compound 8). *p < 0.05 (one way ANOVA plus post-hoc Tukey’s multiple comparison)