title: Calcium in smooth muscle sarcoplasmic reticulum in situ. Conventional and X-ray analytical electron microscopy.
abstract: Numerous electron-opaque deposits appear in the SR of the relaxed smooth muscle cells of the guinea pig Taenia coli that had been treated, before fixation, with a depolarizing medium containing oxalate to precipitate calcium ions in situ. X-ray spectra obtained by spot and line-scanning analyses of these deposits in situ show characteristic calcium signals, thus providing direct evidence for calcium accumulation inside the sarcoplasmic reticulum of smooth muscle.
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis*; D002713:Chlorine / Q000032:analysis; D003106:Colon / Q000648:ultrastructure; D003300:Copper / Q000032:analysis; D006168:Guinea Pigs; D008274:Magnesium / Q000032:analysis; D009130:Muscle, Smooth / Q000032:analysis / Q000648:ultrastructure*; D009992:Osmium / Q000032:analysis; D010070:Oxalates; D011188:Potassium / Q000032:analysis; D012519:Sarcoplasmic Reticulum / Q000032:analysis / Q000648:ultrastructure*; D015032:Zinc / Q000032:analysis
chemical_list: D010070:Oxalates; D009992:Osmium; D002713:Chlorine; D003300:Copper; D008274:Magnesium; D015032:Zinc; D011188:Potassium; D002118:Calcium