HISTOCHEMISTRY, CAPILLARIZATION, AND MITOCHONDRIAL DENSITIES OF MUSCLE FIBERS ISOLATED FROM THE ILIOFIBULARIS MUSCLE OF AGAMA PALLIDA

Abstract

ABSTRACT The histochemical and ultrastructural properties of the fiber types present in the iliofibularis muscle isolated from the lizard Agama pallida have been investigated. On the basis of the histochemical activities of alkaline myofibrillar ATPase (m-ATPase), succinic dehydrogenase (SDH), and α-glycerophosphate dehydrogenase (α-GPDH), the pale (outer) region of the iliofibularis was found to contain fast-twitch-oxidative glycolytic fibers, which stain dark for all three enzymes, and tonic fibers, which stain light for m-ATPase, dark for SDH, and moderate for α-GPDH. The cross-sectional area of the white region is 78%, three times the cross-sectional area of the red region (22%). The ultrastructure of the myofibrils and the sarcoplasmic reticulum in fast fibers was compared with that in tonic fibers. Fast glycolytic and fast oxidative glycolytic fibers had straight Z-lines, clear M-bands, and well developed sarcoplasmic reticulum. Furthermore, glycogen granules and lipid droplets were demonstrated in ...