Histochemical enzyme profile of the masseter muscle in different mammalian species

✍ Scribed by Schiaffino, S.

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: English
• Weight: 680 KB
• Volume: 180
• Category: Article
• ISSN: 0003-276X
• DOI: 10.1002/ar.1091800107

✦ Synopsis

Abstract

It has long been known that in certain mammalian species the masseter muscle is a fast‐twitch muscle in spite of its red colour. We have investigated the histochemical fiber composition of this muscle in the rabbit and in different species of rodents. In the mouse, rat and guinea pig the masseter is uniformly composed of fibers displaying alkali‐stable and acid‐labile myosin ATPase activity like most fibers in fast‐twitch hindleg muscles and moderate to high succinate dehydrogenase activity. The homogeneity of the histochemical profile with respect to myosin ATPase activity makes this muscle especially suitable for correlated physiological, biochemical and ultrastructural studies. The rabbit masseter has a basically similar though relatively heterogeneous fiber composition with atypical histochemical properties. A sizable population of fibers in this muscle exhibit high levels of both alkali‐stable and acid‐stable myosin ATPase activity. Mitochondrial α‐glycerophosphate dehydrogenase activity, which reflects the glycolytic capacity of skeletal muscle fibers, varies in the masseter of different species in a way which cannot be exactly predicted on the basis of the reactions for myosin ATPase and succinate dehydrogenase.