Electrophysiologic features of muscle regeneration

Extracellular and intracellular recordings of directly evoked action potentials were used to detect the restoration of functional continuity in regenerating rat semitendinosus muscle fibers. After a crush lesion, muscle fibers became almost fully depolarized at the site of injury and some decrease in resting potential could be detected several millimeters on either side of the lesion. Functional continuity was reestablished in some fibers by the 5th day and in all fibers by the 30th day after crushing. At first, impulse propagation was delayed in the regenerating segments of fibers but normal response latencies were attained by the 30th day.