title: Simultaneous maturation of transverse tubules and sarcoplasmic reticulum during muscle differentiation in the mouse.
abstract: The development and maturation of transverse (T) tubules and sarcoplasmic reticulum (SR) have been studied in pre- and postnatal mouse muscle, using selective "staining" of these membrane systems. As previously reported in the literature, orderly transverse orientation of the T tubules occurs late in development and early T-SR junctions (triads and dyads) are located at random along the T tubules in a predominantly longitudinal orientation. We find that initial appearance of transverse tubules occurs fairly abruptly, and that all early T tubules have a longitudinal orientation. Transverse orientation of the T tubule network, location of triads at the A-I junction, and development of differentiated regions of the SR are coordinated events which occur gradually over a period of about 3 weeks for leg muscle.s The timing of triad development coincides with that reported for the increase in slow calcium current and dihydropyridine binding. Differences in T tubule patterns between muscle fibers of EDL and soleus are apparent only at relatively late stages.
authors.affiliation: Department of Anatomy, University of Pennsylvania, Philadelphia 19104-6058.
authors.forename: C
authors.initials: C
authors.lastname: Franzini-Armstrong
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D005314:Embryonic and Fetal Development; D005260:Female; D007365:Intercellular Junctions / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D009132:Muscles / Q000196:embryology* / Q000648:ultrastructure; D011247:Pregnancy; D012508:Sarcolemma / Q000502:physiology / Q000648:ultrastructure; D012519:Sarcoplasmic Reticulum / Q000502:physiology* / Q000648:ultrastructure; D013997:Time Factors