title: [Incorporation of 3H-thymidine into the cells of the heart conduction system (sinoatrial and atrioventricular nodes, bundle of His) during cardiogenesis in mice].
abstract: The number of DNA synthesizing myocytes in the conductive system, as compared with the working myocardium, was determined by means of light autoradiography. At the same time the number of mitosing cells was counted. The indices of labelled nuclei in the sinoatrial and atrioventricular nodes of the embryos after the single and repeated 3H-thymidine injections were significantly lower than in the working ventricle and atrium. During the postnatal development (3-11 days) only in the sinoatrial node the index of labelled nuclei was significantly lower than in the working ventricle. The proliferative activity in all the myocardium parts fell markedly by the 13th day of development. Following 10 3H-thymidine injections with 12 hrs intervals, the indices of labelled nuclei varied from 0.03 to 0.67% in the working ventricle and atrium and from 0.13 to 1.0% in the conductive system of adult mice. During the embryogenesis the index of labelled nuclei in the sinoatrial node was significantly higher than in the atrioventricular one and during the postnatal development-vice versa.
mesh_terms: D000818:Animals; D001283:Atrioventricular Node / Q000166:cytology / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D002036:Bundle of His / Q000166:cytology / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D002452:Cell Count; D004247:DNA / Q000096:biosynthesis*; D006329:Heart Conduction System / Q000166:cytology / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D051379:Mice / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D008938:Mitosis; D012849:Sinoatrial Node / Q000166:cytology / Q000196:embryology / Q000254:growth & development / Q000378:metabolism
chemical_list: D004247:DNA
vernacular_title: Vkliuchenie 3H-timidina v kletki provodiashcheĭ sistemy serdtsa (sinoatrial'nyĭ i atrioventrikuliarnyĭ uzly, puchok Gisa) v protsesse kardiogeneza myshi.