Summary
The three-dimensional structure of the sarcoplasmic reticulum (SR) in the red, white and intermediate striated muscle fibers of the extensor digitorum longus muscle of the rat was examined under a field-emission type scanning electron microscope after removal of cytoplasmic matrices by the osmium-DMSO-osmium procedure.
In all three types of fibers, the terminal cisternae and transverse tubules form triads at the level of the A-I junction. Numerous slender sarcotubules, originating from the A-band side terminal cisternae, extend obliquely or longitudinally and form oval or irregular shaped networks of various sizes in front of the A-band, then become continuous with the tiny mesh (fenestrated collar) in front of the H-band. The A-and H-band SR appears as a single sheet of anastomotic tubules. Numerous sarcotubules, originating from the I-band side terminal cisternae, extend in threedimensional directions and form a multilayered network over the I-band and Z-line regions. At the I-band level, paired transversely oriented mitochondria partly embrace the myofibril. The I-band SR network is poorly developed in the narrow space between the paired mitochondria, but is well developed in places devoid of these mitochondria.
The three-dimensional structure of the SR is basically the same in all three muscle fiber-types. However, the SR is sparse on the surface of mitochondria, so the mitochondria-rich red fiber has a much smaller total volume of SR than the mitochondria-poor white fiber. Moreover, the volume of SR of the intermediate fiber is intermediate between the two.
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Andersson-Cedergren E (1959) Ultrastructure of motor end plate and sarcoplasmic components of mouse skeletal muscle fibre as revealed by three-dimensional reconstructions from serial sections. J Ultrastruct Res Suppl 1:5–191
Cullen MJ, Hollingworth S, Marshall MW (1984) A comparative study of the transverse tubular system of the rat extensor digitorum longus and soleus muscles. J Anat 138:297–308
Eisenberg BR, Kuda AM (1975) Stereological analysis of mammalian skeletal muscle. II. White vastus muscle of the adult guinea pig. J Ultrastruct Res 51:176–187
Eisenberg BR, Kuda AM, Peter JB (1974) Sterological analysis of mammalian skeletal muscle. I. Soleus muscle of the adult guinea pig. J Cell Biol 60:732–754
Franzini-Armstrong C (1963) Pores in the sarcoplasmic reticulum. J Cell Biol 19:63 7–641
Gauthier GF (1969) On the relationship of ultrastructural and cytochemical features to color in mammalian skeletal muscle. Z Zellforsch 95:462–482
Ogata T, Murata F (1969) Cytological features of three fiber types in human striated muscle. Tohoku J Exp Med 99:225–245
Ogata T, Yamasaki Y (1985) Scanning electron-microscopic studies on the three-dimensional structure of mitochondria in the mammalian red, white and intermediate muscle fibers. Cell Tissue Res 241:251–256
Omori T, Kashima Y, Osatake H (1983) Three-dimensional architecture of sarcotubules of rat skeletal and heart muscle cells observed by SEM. J Electron Microsc 32:262
Peachey LD (1965) The sarcoplasmic reticulum and transverse tubules of the frog's sartorius. J Cell Biol 25:209–231
Porter KR, Palade GE (1957) Studies on the endoplasmic reticulum. HI. Its form and distribution in striated muscle cells. J Biophys Biochem Cytol 3:269–300
Rambourg A, Segretain D (1980) Three-dimensional electron microscopy of mitochondria and endoplasmic reticulum in the red muscle fiber of the rat diaphragm. Anat Rec 197:33–48
Revel JP (1962) The sarcoplasmic reticulum of the bat cricothyroid muscle. J Cell Biol 12:571–588
Sawada H, Ishikawa H, Yamada E (1978) High resolution scanning electron microscopy of frog sartorius muscle. Tissue & Cell 10:179–190
Scales DJ, Yasumura T (1982) I. Stereoscopic views of a dystrophic sarcotubular system: selective enhancement by a modified Golgi stain. J Ultrastruct Res 78:193–205
Schiaffino S, Hanzliková V, Pierobon S (1970) Relations between structure and function in rat skeletal muscle fibers. J Cell Biol 47:107–119
Sommer JR (1982) The anatomy of the sarcoplasmic reticulum in vertebrate skeletal muscle: Its implications for excitation contraction coupling. Z Naturforsch 37:665–678
Tanaka K, Naguro T (1981) High resolution scanning electron microscopy of cell organelles by a new specimen preparation method. Biomed Res 2 Suppl pp 63–70
Tomanek RJ, Asmundson CR, Cooper RR, Barnard RJ (1973) Fine structure of fast-twitch and slow-twitch guinea pig muscle fibers. J Morphol 139:47–66
Waugh RA, Spray TL, Sommer JR (1973) Fenestrations of sarcoplasmic reticulum. Delineation by lanthanum acting as a fortuitous tracer and in situ negative stain. J Cell Biol 59:254–260
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Ogata, T., Yamasaki, Y. Scanning electron-microscopic studies on the three-dimensional structure of sarcoplasmic reticulum in the mammalian red, white and intermediate muscle fibers. Cell Tissue Res. 242, 461–467 (1985). https://doi.org/10.1007/BF00225410
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DOI: https://doi.org/10.1007/BF00225410