Blood flow regulates myocardial Erbb2 and BMP signaling through endocardial Notch. (A–F) Confocal imaging of BRE:d2GFP; vmhc:mCherry-NTR hearts at 48 hpt (7 dpf) shows that (B) BRE:d2GFP is activated after ventricular ablation (n = 21/21) when compared to (A) uninjured control hearts (n = 0/29); however, (D) blebbistatin (Blebb) (n = 0/11) or (F) DAPT (n = 0/14) treatment inhibits this BRE:d2GFP injury-induced activation. (G–R) Whole-mount in situ hybridizations reveal that bmp10 and nrg1 expression are increased in vmhc:mCherry–NTR (H, N) ventricle-ablated hearts (n = 13/14 bmp10; 7/8 nrg1) at 48 hpt (7 dpf) when compared to (G, M) control uninjured hearts (n = 0/18 bmp10; 0/13 nrg1), while treatment with (J, P) blebbistatin (n = 2/13 bmp10; 0/6 nrg1) or (L, R) DAPT (n = 4/16 bmp10; 0/7 nrg1) inhibits the injury-induced activation of bmp10 and nrg1. All confocal images shown are maximum intensity projections. V, ventricle; A, atrium; dpf, days post fertilization; hpt hours post-MTZ/DMSO treatment. Dashed lines outline the heart. Bars: 50 μm. The following figure supplements are available for Figure 7.