A histological and histochemical study of changes of fiber types in experimental myotonia.
In both fast and slow muscles of rats treated with 20--25 diazacholesterol there were qualitative alterations, such as changes of fiber outlines, numerous moth-eaten fibers and rare ring fibers. In addition there were generally larger groups of Type I and intermediate fibers than in normal controls ("type-grouping" tendency) in the preparations for oxidative enzymes in the extensor digitorum longus (EDL) of myotonic animals. Quantitative evaluations of EDL and soleus of myotonic rats revealed moderate hypothrophy of Type I and Type II fibers with an increase in the numbers of Type I and of Type III fibers in the EDL and a significant decrease of the nondominant fibers in the soleus muscle. The data are discussed in the light of a neurally mediated and/or direct action of the drug on the muscle fiber.
D000818:Animals; D001373:Azacosterol; D005260:Female; D008931:Mitochondria, Muscle / Q000473:pathology; D009132:Muscles / Q000032:analysis / Q000473:pathology*; D009222:Myotonia / Q000139:chemically induced / Q000209:etiology / Q000473:pathology*; D010523:Peripheral Nervous System Diseases / Q000150:complications; D051381:Rats; D013194:Staining and Labeling
D001373:Azacosterol