System for measuring isolated rat soleus muscle belly response to tetanic stimulation

A novel system for simultaneous measurements of isotonic muscle contraction and transversal muscle belly displacement in the isolated rat soleus muscle was designed. The system simultaneously records tetanic contraction of the muscle and transversal displacements of the muscle belly. The tetanic rise times (TRT) and muscle belly displacement times (BDRT) were measured at different proton loads induced by CO₂ at 1%, 5% and 30%. The measurements of muscle belly displacement enabled us to follow the water shift into the muscle tissue during the tetanic activity. Acidosis provoked by 30% CO₂ irreversibly increased the BDRT, however the TRT were not changed.