FIBER TYPES DISTRIBUTION IN THE DIGASTRIC MUSCLE OF TUFTED CAPUCHIN MONKEY (CEBUS-APELLA)

Fiber types distribution in the diagastric muscle of tufted capuchin m onkey was studied by means of NADH-TR, myosin-ATPase, after alkaline a nd acid preincubations and SDH histochemical reactions. Three differen t types of fibers were found presenting an equal distribution. The per centage and types of fibers were as follow: 18.2 % SO (Slow Oxydative) , 38.4 % FOG (Fast Oxydative Glycolytic) and 43.4 % FG (Fast Glycolyti c). FG fibers revealed the largest area. The relatively high concentra tion of fast twitch (81.2 %) seems to indicate this muscle is involved with the acceleration and fast speed of jaw movements. Aerobic metabo lism represented by SO + FOG fibers (56.6 %) suggests that this muscle possesses an additional role than that related to the lowering of the jaw.