Muscle Fiber Conduction Velocity of Denervated Muscles in the Rat

Abstract

We investigated the changes of muscle fiber conduction velocities (MFCV) and myopathology in denervated extensor digitorum longus (EDL) and soleus (SOL) muscles following sciatic nerve section in 29 adult Wistar rats. Although muscle fiber diameter of SOL was larger than that of EDL, MFCV of the SOL was slower than the EDL. SOL was composed mainly of type 1, and EDL manly of type 2 fibers. After denervations, muscle weight, fiber diameter, and MFCV decreased. The decrement of MFCV was abrupt after denervations as compared with gradual decrease of the weight and diameter. Results indicated that denervation itself, probably changing the sarcolemmal excitability, may play a role in the early delay of the MFCV.