Skip to main content
. Author manuscript; available in PMC: 2011 Apr 30.
Published in final edited form as: Circ Res. 2010 Mar 25;106(8):1342–1350. doi: 10.1161/CIRCRESAHA.109.213132

FIGURE 3. Sodium channel morphant embryos have reduced numbers of embryonic cardiomyocytes.

FIGURE 3

A–H. Confocal reconstructions of hearts of control Tg(cmlc2:GFP) embryos (A, C) or clutchmates injected with the scn5Laa translation inhibitor morpholino (AA_MO1) (B, D) illustrate that sodium channels are required for normal numbers of embryonic cardiomyocytes. Arrows, ventricle and arrowheads, atrium at 58hpf (A, B) and 104hpf (C, D), respectively. Higher magnification of ventricular and atrial chambers presented in A’, B’ and A”, B”, respectively, illustrate similar chamber-specific cellular morphology in both control (A’, A”) and morphant (B’, B”) embryos. Scale bars = 50µm (A, B, C, D) and 20µm (A’, A”, B’, B”). E, F. Serial confocal sections through the ventricular chamber of control embryos revealed trabeculation by 104hpf (arrows in F). Scale bar = 20µm. G, H. At the same timepoint, scn5Laa morphant ventricles remained a single layer (shown are ventricles from two different morphant embryos). Scale bars = 20µm. I. Confocal reconstructions of the embryonic heart in Tg(cmlc2:DsRed2-nuc) embryos permitted quantification of deficits of embryonic cardiomyocytes in morphant embryos at 60–62hpf. Scn5Laa and scn5Lab morphant hearts have significantly fewer embryonic cardiomyocytes than those of mismatch control morpholino-injected clutchmates and embryos injected with a morpholino targeting the zerg cardiac potassium channel. Results are mean ± s.e.m. (N) in bar graph = number of hearts analyzed. *, P<0.01 versus AA_MIS1 and †, P<0.01 versus AB_MIS1, ANOVA. Embryos injected with both AA_MO1 and AB_MO2 morpholinos (scn5Laa, scn5Lab double knockdown) had fewer cardiomyocytes than embryos injected with either AA_MO1 or AB_MO2 alone (177±8 versus 228±14 and 226±12, respectively) but the results were not statistically significant following ANOVA of all 7 groups. Where indicated, p53 morpholino was co-injected with active morpholinos as a control for non-specific morpholino toxicity. Photos are representative wild type, scn5Laa control, and scn5Laa morphant embryo hearts at 78hpf. Arrows, ventricle. Arrowheads, atrium. Scale bars = 50µm.