title: The localization of calcium by X-ray microanalysis in myopathic muscle fibers.
abstract: An electron histochemical study was undertaken to localize calcium with ammonium oxalate precipitation technique in soleus muscle of rat in normal cases and in myopathy induced experimentally by a prolonged treatment of 2,4-dichlorophenoxyacetate (2,4-D). The calcium content of precipitates was detected by energy-dispersive X-ray microanalysis. In normal cases, the electron dense precipitates containing calcium were mainly found in the vesicles of sarcoplasmic reticulum, whereas in 2,4-D induced myopathy the deposits were shifted near the Z line into the myofibrils. Calcium, because the uptake into sarcoplasmic vesicles was inhibited by 2,4-D, could attach to other binding sites, such as to the troponin-C.A long-lasting binding of calcium might lead to a prolonged activation of the actin-myosin system.
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000009:adverse effects; D000818:Animals; D002118:Calcium / Q000302:isolation & purification*; D004577:Electron Probe Microanalysis; D005260:Female; D006651:Histocytochemistry; D008297:Male; D009132:Muscles / Q000032:analysis*; D009135:Muscular Diseases / Q000139:chemically induced / Q000378:metabolism*; D009210:Myofibrils / Q000032:analysis; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000032:analysis
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid; D002118:Calcium