Abstract: | A quantitative histochemical study was carried out on axial musculature of Noemacheilus barbatulus L. On the basis of succinate dehydrogenase (SDH) and myofibrillar ATP-ase activity, 5 types of muscle fibers are described. When the SDH method was used, red, tonic, intermediate, and white muscle fibers were easily observed. However, histochemical reaction for myofibrillar ATP-ase activity, after alkaline preincubation (pH = 10.4), revealed another type of fiber zone laying between the intermediate and white muscle fiber regions and forming a transitional zone. Electron microscopic observation showed significant differences in sarcomere organization and thickness of myosin filaments of the various muscle fiber types. |