Myofibrils and transverse tubules in glycerol-treated frog skeletal muscle.

Effects of glycerol (400 mM) on the structure of frog skeletal muscle were reported based on measurements of the diameters of myofibrils and transverse tubules (T-tubules). The diameter of the myofibrils decreased to about 0.58 micron from the normal size of 0.79 micron during glycerol treatment, but the spacing between the myofibrils became wider. The size did not recover to the initial value even after return of the muscle to the Ringer solution. T-tubule diameters increased to 35-55 nm from the normal size of about 30 nm in glycerol-treated muscle, and the size was maintained after return of the muscle to the Ringer solution.