Histochemical studies on the red, white and intermediate muscle fibers of some skeletal muscles. Ⅲ. Histochemical demonstration of oxidative enzymes, phosphorylase and glycogen in respiratory muscle fibers

1) Three different types of muscle fibers were clearly distinguished in the intercostal muscles and the diaphragm of human, cat and rat by histochemical demonstration of oxidative enzymes, phosphorylase and glycogen. 2) The intercostal muscles and diaphragm each presented dissimilar patterns of the muscle fibers. The diaphragm did not show any definite correlation between the diameter and the histochemical reaction of muscle fibers but its red fibers indicated a more intense uptake of Nitro-BT formazan deposits in the subsarcolemmal region. In this conection, the relationship between the motor innervation and histochemical evaluation of the diaphragm was described. 3) Phosphorylase and glycogen showed reciprocal reactions to the oxidative enzyme activity. They were generally high in large fibers but low in small fibers, and moderate in intermediate fibers.