The differentiation of the myofibrils and the intermediate filament system during postnatal development of the rat heart has been investigated. Several aspects of some of the structural proteins: the intermediate filament subunit skeletin, myosin, and the myofibrillar M-line proteins MM-creatine kinase and myomesin have been studied by using gel electrophoresis as well as enzyme and immunohistochemical techniques in combination with electron microscopy of both plastic and cryosectioned material. We show that marked changes take place in the organization of the intermediate filament system and in the contractile apparatus, both in atria and in ventricles of the rat heart during postnatal development. In the newborn rats no dense myofibrillar M-bands were present in the M-region and the sarcomeric bands were irregular, while in the 4-week-old rats dense M-bands composed of a set of 5 crossbridges interconnecting the thick filaments were present. The sarcomeric bands were not regular. These observations are related to the presence of different isomyosins in the atria and in the ventricles of the newborn and the 4-week-old rats, to the observations that MM-creatine kinase was only present in the M-region in the 4-week-old rats and to the physiological maturation of the heart.
|Original language||English (US)|
|Number of pages||12|
|Journal||European Journal of Cell Biology|
|State||Published - Dec 1 1982|
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Cell Biology