[ATPase systems of the skeletal muscle sarcolemma in E-avitaminotic muscular dystrophy]

The sarcolemma preparations isolated from the skeletal muscles of the normal rabbits and those with E-avitaminosis are characterized by electron microscopy according to the activity of 5-nucleotidase and different ATPase systems. As the data of electron microscopy evidence, the sarcolemma preparations of the normal and dystrophic muscles are deprived of admixtures of other subsellular structures. The 5-nucleotidase activity in the sarcolemma of dystrophic muscles is almost thrice as high as in the sarcolemma of normal muscles. On the basis of the results of studies in the kinetic parameters the optimal conditions are selected to investigate the Mg2+, Ca2+ and Na+, K+-ATPase activity. It is shown that under dystrophy the ATPase activity in the sarcolemma preparations in the presence of Ca2+ and Mg2+ does not change as compared to the norm. As to the Mg2+-dependent Na+, K+-ATPase system its activity in sarcolemma of muscles under dystrophy lowers noticeably. Ouabain-sensitive Na+, K+-ATPase of sarcolemma under dystrophy is considerably lower than at the normal level and is 4.1 and 12.1 mumol and phi n per 1 mg of protein for 1 h, respectively. Proceeding from the data on the changes in the lipid composition of sarcolemma of muscles with E-avitaminous dystrophy a problem is under discussion concerning dependence of the transport Na+, K+-ATPase activity on the structure of sarcolemma.