Anatomy and Embryology

, Volume 211, Issue 2, pp 95–100 | Cite as

Mode and determination of the initial contraction stage in the mouse embryo heart

  • Kiyomasa NishiiEmail author
  • Yosaburo Shibata
Original Article


The developing mammalian heart initiates spontaneous contractions shortly after the myocardium differentiates from the splanchnic mesoderm. The precise timing and mode of the onset of heartbeat, however, have not been statistically described in mice. We analyzed the patterns of contractive activity in video-recorded heart regions ranging from the pre-somite stage to day 10.5 (E10.5). The first sign was detected at the 3-somite stage (E8.25), when a few cardiac myocytes constituted small contracting groups on both sides of the heart tube. Fluctuations of the basal [Ca2+]i level were detected in dormant 3-somite-stage hearts, indicating the initiation of electrical activity before visible contractions. After weak and irregular contractions at the 3-somite stage, the contractions were almost coordinated as early as the 4-somite stage. Unidirectional blood flow through the atrioventricular canal was established around the 20-somite stage at E9.25, correlated with the development of the endocardial cushion. We propose that not only the endocardial cushion but also coordinated contractions are essential for unidirectional flow, because induced bradycardia due to short exposure at room temperature caused regurgitation at E10.5 when otherwise highly organized flow was observed. These findings complement and extend earlier observations on functional heart development, providing a reference for fundamental research on mammalian cardiogenesis.


Development Endocardial cushion First contractions Heart Mouse 



We thank Kanako Hashizume and Yumi Miyano for their technical assistance, Mamiko Kamizono and Takeyo Omura for their care of the experimental animals, and Dr. Sachio Morimoto (of the Department of Clinical Pharmacology) for allowing us to use the [Ca2+]i-recording equipment. This work was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (No. 16790126 to K.N. and No. 17390052 to Y.S.).

Supplementary material

Supplementary materials









  1. Egashira K, Nishii K, Nakamura K, Kumai M, Morimoto S, Shibata Y (2004) Conduction abnormality in gap junction protein connexin45-deficient embryonic stem cell-derived cardiac myocytes. Anat Rec 280A:973–979CrossRefGoogle Scholar
  2. Franco D, Lamers WH, Moorman AFM (1998) Patterns of expression in the developing myocardium: towards a morphologically integrated transcriptional model. Cardiovasc Res 38:25–53PubMedCrossRefGoogle Scholar
  3. Goss CM (1938) The first contractions of the heart in rat embryos. Anat Rec 70:505–524CrossRefGoogle Scholar
  4. Hirota A, Kamino K, Komuro H, Sakai T, Yada T (1985) Early events in development of electrical activity and contraction in embryonic rat heart assessed by optical recording. J Physiol 369:209–227PubMedGoogle Scholar
  5. Hogan B, Beddington R, Costantini F, Lacy E (1994) Manipulating the mouse embryo: a laboratory manual. Cold Spring Harbor, Cold Spring Harbor, New YorkGoogle Scholar
  6. Huang GY, Linask KK (1998) Doppler echocardiographic analysis of effects of tribromoethanol anesthesia on cardiac function in the mouse embryo: a comparison with pentobarbital. Lab Anim Sci 48:206–209PubMedGoogle Scholar
  7. Ji RP, Phoon CKL, Aristizábal O, McGrath KE, Palis J, Turnbull DH (2003) Onset of cardiac function during early mouse embryogenesis coincides with entry of primitive erythroblasts into the embryo proper. Circ Res 92:133–135PubMedCrossRefGoogle Scholar
  8. Kamino K (1991) Optical approaches to ontogeny of electrical activity and related functional organization during early heart development. Physiol Rev 71:53–91PubMedGoogle Scholar
  9. Kaufman MH, Navaratnam V (1981) Early differentiation of the heart in mouse embryos. J Anat 133:235–246PubMedGoogle Scholar
  10. Kumai M, Nishii K, Nakamura K, Takeda N, Suzuki M, Shibata Y (2000) Loss of connexin45 causes a cushion defect in early cardiogenesis. Development 127:3501–3512PubMedGoogle Scholar
  11. Linask KK, Han MD, Artman M, Ludwig CA (2001) Sodium–calcium exchanger (NCX-1) and calcium modulation: NCX protein expression patterns and regulation of early heart development. Dev Dyn 221:249–264PubMedCrossRefGoogle Scholar
  12. McGrath KE, Koniski AD, Malik J, Palis J (2003) Circulation is established in a stepwise pattern in the mammalian embryo. Blood 101:1669–1676PubMedCrossRefGoogle Scholar
  13. Navaratnam V, Kaufman MH, Skepper JN, Barton S, Guttridge KM (1986) Differentiation of the myocardial rudiment of mouse embryos: an ultrastructural study including freeze-fracture replication. J Anat 146:65–85PubMedGoogle Scholar
  14. Nishii K, Kumai M, Shibata Y (2001) Regulation of the epithelial–mesenchymal transformation through gap junction channels in heart development. Trends Cardiovasc Med 11:213–218PubMedCrossRefGoogle Scholar
  15. Nishii K, Kumai M, Egashira K, Miwa T, Hashizume K, Miyano Y, Shibata Y (2003) Mice lacking connexin45 conditionally in cardiac myocytes display embryonic lethality similar to that of germline knockout mice without endocardial cushion defect. Cell Commun Adhesion 10:365–369CrossRefGoogle Scholar
  16. Phoon CKL, Ji RP, Aristizábal O, Worrad DM, Zhou B, Baldwin HS, Turnbull DH (2004) Embryonic heart failure in NFATc1 -/- mice: novel mechanistic insights from in utero ultrasound biomicroscopy. Circ Res 95:92–99PubMedCrossRefGoogle Scholar
  17. Rentschler S, Vaidya DM, Tamaddon H, Degenhardt K, Sassoon D, Morley GE, Jalife J, Fishman GI (2001) Visualization and functional characterization of the developing murine cardiac conduction system. Development 128:1785–1792PubMedGoogle Scholar
  18. Rentschler S, Zander J, Meyers K, France D, Levine R, Porter G, Rivkees SA, Morley GE, Fishman GI (2002) Neuregulin-1 promotes formation of the murine cardiac conduction system. Proc Natl Acad Sci USA 99:10464–10469PubMedCrossRefGoogle Scholar
  19. Rothenberg F, Efimov IR, Watanabe M (2004) Functional imaging of the embryonic pacemaking and cardiac conduction system over the past 150 years: technologies to overcome the challenges. Anat Rec 280A:980–989CrossRefGoogle Scholar
  20. Virágh S, Challice CE (1977) The development of the conduction system in the mouse embryo heart: I. The first embryonic A–V conduction pathway. Dev Biol 56:382–396PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of Developmental Molecular Anatomy, Graduate School of Medical ScienceKyushu UniversityFukuokaJapan
  2. 2.Department of Cell BiologyTokyo Medical and Dental UniversityBunkyo-kuJapan

Personalised recommendations