A new method has been developed for mechanically disrupting the sarcolemma of mammalian sketletal muscle fibers (sarcolemma nonfunctional). Single fibers were produced from small pieces of the soleus muscle of the rabbit by gentle homogenization in a relaxing solution in a tissue homogenizer. These fibers were found to be longitudinally intact, with a sarcomere spacing of approximately 2.1 mum, permeable to large molecules of 10,000 MW, sensitive to the chemical stimuli that cause Ca2+ to be released from the sarcoplasmic reticulum, and responsive to Ca2+ in the same manner as frog fibers skinned in the traditional manner. The single fibers were mounted in a tension transducer and steady-state tensions were recorded in test solutions of different Ca2+ concentrations. The data did not differ statistically from data similarly obtained in identically prepared fibers that, in addition, we had longitudinally split in half to ensure disruption of the sarcolemmal barrier to the diffusion of ions.
- Copyright © 1975 the American Physiological Society