Figure 2. Parallels between zebrafish and human physiology and pharmacology.
(1a) Ventricular action potential (AP) durations in wildtype (wt) and breakdance heterozygotes (+/−) and homozygotes (−/−) at 6 days post fertilization. * denotes p<0.05. (1b) Typical ventricular APs are displayed for wildtype, breakdance heterozygote and homozygote embryos. The heterozygote AP is subtly prolonged, while the homozygote shows marked AP prolongation. Vertical calibration bar denotes 20% ΔF/F0, horizontal bar denotes 100ms. (1b) Upper panel: simultaneous atrial and ventricular voltage recordings from breakdance (−/−) heart showing the mechanism of 2:1 atrioventricular block: APs are so prolonged in the ventricle that alternate atrial impulses encroach on the refractory plateau of the previous ventricular repolarization. Lower panel: Early afterdepolarizations (arrows) in breakdance (−/−) embryos during ventricular pacing; the pacing train is shown below the AP recording. (1d) Heterozygote breakdance embryos display increased sensitivity to 10nM dofetilide.