Figure 5

Incubation and washout of para-aminoblebbistatin in 3 dpf Tg(myl7:Twitch-4) zebrafish larvae. (A) Atrial and ventricular average Ca²⁺ levels (Twitch-4 emission ratio) and fractional area change (FAC) in control larvae (n = 18), in larvae during incubation with 75 µM para-aminoblebbistatin (PAB 1 h, n = 8, and PAB 2 h, n = 22), and in larvae during washout after 2 h of PAB treatment (washout 2 h, n = 20, and washout 4 h, n = 20). Statistical analysis was performed using a one-way ANOVA test with Dunnett’s multiple comparisons post-test. Data are shown as the mean ± SD (** p < 0.01, *** p < 0.001, **** p < 0.0001). (B) Inverse correlation between heart contraction and Ca²⁺ levels (Twitch-4 emission ratio) of individual larvae before (control), after incubation with 75 µM PAB (1 or 2 h), and after washout of PAB (2 or 4 h). A linear regression test was performed, and the coefficient of correlation (R²) was calculated.