Both dicoumarol and BAPTA-AM rescued the erythrocyte-deficiency in circulation and heart-looping defect phenotypes in β-lapachone-treated embryos. Embryos at 24 hours post-fertilization (hpf) were treated with either 0.2% DMSO (A, B), 5 μM dicoumarol (C, D), 2 μM β-lapachone (E, F), or 2 μM β-lapachone and 5 μM dicoumarol (G, H) for 4 h and fixed for nppa hybridization and o-dianisidine (ODA) staining at 48 hpf. Higher-magnification ODA-stained images of the ventral tail region are shown (B, D, F, H). (I, J) Evaluation of the rescue effects by dicoumarol or BAPTA-AM. Error bars indicate the standard error. Scale bars represent 100 μm.