title: Self-beating atypically shaped cardiomyocytes survive a long-term postnatal development while preserving the expression of fetal cardiac genes in mice.
abstract: The present study was designed to examine the postnatal developmental changes of atypically shaped cardiomyocytes (ACMs) prepared from the heart of newborn [postnatal day 1 (day-1)] through aged (12-month-old) mice. ACMs were identified as a novel type of self-beating cardiomyocyte with a peculiar morphology in mouse cardiac ventricles. The cell length of ACMs significantly increased during the first three postnatal months and further increased over the following 9 months. In contrast, the population of ACMs was significantly decreased within the first 5 weeks and reached a plateau in the adult stage. ACMs obtained from newborn and adult mice exhibited similar spontaneous action potentials. The expression of the fetal cardiac gene products atrial natriuretic peptide and voltage-gated T-type Ca(2+) channel Ca(V)3.2 was confirmed by immunostaining in ACMs obtained from both newborn and aged mice. These observations provide evidence that ACMs that exhibit spontaneous beating survive the long-term postnatal development of cardiac ventricles while preserving the expression of fetal cardiac genes. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
authors.affiliation: Department of Physiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan. m_omatsu@belle.shiga-med.ac.jp
authors.forename: Mariko
authors.initials: M
authors.lastname: Omatsu-Kanbe
authors.forename: Takefumi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuura
mesh_terms: D000200:Action Potentials; D000375:Aging / Q000235:genetics / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D020747:Calcium Channels, T-Type / Q000235:genetics / Q000502:physiology; D048429:Cell Size; D002470:Cell Survival; D005260:Female; D047109:Fetal Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology* / Q000502:physiology; D006339:Heart Rate; D006352:Heart Ventricles / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D032342:Muscle Cells / Q000166:cytology / Q000502:physiology; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology*; D011247:Pregnancy
chemical_list: D020747:Calcium Channels, T-Type