K. Sugasawa et al., HISTOCHEMICAL AND ELECTRON-MICROSCOPIC PROPERTIES OF THE MASSETER-MUSCLE IN THE JAPANESE FIELD-VOLE MICROTUS-MONTEBELLI, Zoological science, 14(2), 1997, pp. 369-374
The masseter muscles of the Japanese field vole Microtus montebelli we
re studied histochemically and electron microscopically. The masseter
muscles were composed of only fast-twitch oxidative (FO) fibers. As to
ultrastructural features of the fibers, mitochondria, sarcoplasmic re
ticula and transverse tubules were well developed. It is concluded tha
t the masseter muscles in M. montebelli have the structural characteri
stics that they can contract fast and enduringly. Thus, they appear to
be highly adapted to herbivorous food habit.