[Electrophysiologic, morphometric and histocytochemical characteristics of frog sartorius muscle fibers].

Three groups of muscle fibers (dark, light, and intermediate) were revealed in the fibers of the frog sartorius muscle in examination of the succinate dehydrogenase (SDH) activity. There was revealed a reverse relationship between the diameter of the muscle fibers an the SDH activity in them. The external surface of sartorius muscle is chiefly represented by dark muscle fibers, whereas the internal one--by light ones. Microelectrode study demonstrated that the fibers of the external surface were characterized, in comparison with those of the internal one, by lesser action potentials, prolonged trace negative potential, low quant composition of the end plate potentials, high amplitude and low frequency of the end plate miniature potentials. Analysis of the data obtained demonstrated definite interrelationship between the histochemical profile of the muscle fibers of the frog sartorius muscle and their electrophysiological characteristics.