Abstract
An electron microscope study has been made of the distribution of membrane couplings between the sarcoplasmic reticulum (SR) and either the plasmalemma or the T tubules in fetal and neonatal rat intercostal muscle. Within primitive muscle cells at 12 days of gestation, the SR forms both simple and specialized membrane junctions with the plasmalemma; caveolae are very few, and T tubules are not detected. Undifferentiated cells neighbor muscle cells. Occasionally these cells contain subsurface couplings between the endoplasmic reticulum and plasmalemmae. Possible relationships between these couplings and the peripheral couplings of muscle cells are discussed. By 15–18 days of gestation, caveolae and beaded T tubules, comparable to those of cultured muscle, develop; T tubules lie along-side myofibrils and are rarely transverse. SR couples both to T tubules and to plasmalemmae during this period. T tubules with lineal profiles appear after further development and their orientation transverse to A–I junctions becomes increasingly evident. Membrane couplings between SR and T tubules also increase in number, whereas the incidence of peripheral coupling declines rapidly Evidence suggests that peripheral couplings are swept into myotubes as caveolae proliferate and T tubules form. SR thus appears to initially couple with the plasmalemma and then to await T tubular growth. This contrasts with the developmental pattern described in cultured chick muscle in which peripheral couplings are not reported and T tubules with diads and triads occur at very primitive stages of muscle differentiation.
Full Text
The Full Text of this article is available as a PDF (1.2 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ishikawa H. Formation of elaborate networks of T-system tubules in cultured skeletal muscle with special reference to the T-system formation. J Cell Biol. 1968 Jul;38(1):51–66. doi: 10.1083/jcb.38.1.51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson E. A., Sommer J. R. A strand of cardiac muscle. Its ultrastructure and the electrophysiological implications of its geometry. J Cell Biol. 1967 Apr;33(1):103–129. doi: 10.1083/jcb.33.1.103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kumegawa M., Cattoni M., Rose G. G. Electron microscopy of oral cells in vitro. II. Subsurface and intracytoplasmic confronting cisternae in strain KB cells. J Cell Biol. 1968 Mar;36(3):443–452. doi: 10.1083/jcb.36.3.443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBLUTH J. Subsurface cisterns and their relationship to the neuronal plasma membrane. J Cell Biol. 1962 Jun;13:405–421. doi: 10.1083/jcb.13.3.405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siegesmund K. A. The fine structure of subsurface cisterns. Anat Rec. 1968 Oct;162(2):187–196. doi: 10.1002/ar.1091620206. [DOI] [PubMed] [Google Scholar]
- Trelstad R. L., Revel J. P., Hay E. D. Tight junctions between cells in the early chick embryo as visualized with the electron microscopy. J Cell Biol. 1966 Oct;31(1):C6–10. doi: 10.1083/jcb.31.1.c6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- VERATTI E. Investigations on the fine structure of striated muscle fiber read before the Reale Istituto Lombardo, 13 March 1902. J Biophys Biochem Cytol. 1961 Aug;10(4):1–59. doi: 10.1083/jcb.10.4.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Walker S. M., Schrodt G. R. Triads in foetal skeletal muscle. Nature. 1967 Dec 9;216(5119):985–988. doi: 10.1038/216985a0. [DOI] [PubMed] [Google Scholar]
- YAMADA E. The fine structure of the gall bladder epithelium of the mouse. J Biophys Biochem Cytol. 1955 Sep 25;1(5):445–458. doi: 10.1083/jcb.1.5.445. [DOI] [PMC free article] [PubMed] [Google Scholar]