Sarcoplasmic reticulum and intermediate filament organization in cultured neonatal cardiac muscle cells. Studies with reduced osmium ferrocyanide.
Cardiac muscle cells from 3-day-old rat neonates were cultured for periods of 2 to 56 days. In order to facilitate ultrastructural studies on the organization of the sarcoplasmic reticulum, the cells were prepared for transmission electron microscopy according to a regimen including postfixation in reduced osmium ferrocyanide. The nonjunctional sarcoplasmic reticulum (NJSR) was organized as a loose, fenestrated sleeve around the exterior of bundles of myofilaments and was particularly prominent at the level of the Z line. The only recognizable junctional elements of the sarcoplasmic reticulum were in a peripheral location. Reduced osmium ferrocyanide was also useful in distinguishing intermediate (10 nm) filaments, since it understained Z substance, which often obscured these structures. Intermediate filaments were arranged both at the Z line and the intercalated disc, in parallel strands, approximately at right angles to the myofilaments.
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000648:ultrastructure*; D005295:Ferrocyanides; D005404:Fixatives; D008854:Microscopy, Electron; D009206:Myocardium / Q000648:ultrastructure*; D009993:Osmium Tetroxide; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000648:ultrastructure*
D005295:Ferrocyanides; D005404:Fixatives; C031835:potassium ferrocyanide; D009993:Osmium Tetroxide