Recovery of the Membrane Potential of the Sectioned Striated Muscle Fibers of the Guinea-pig Cremaster

Abstract

We investigated changes in membrane potential after small transections (2-4 mm) of the striated muscle of the guinea-pig cremaster and the rate of penetration of procion yellow (1-5 mg/ml) into the injured fibers. Transverse severance of the striated muscle fibers was followed by a marked drop of the membrane potential near the site of injury, such a fall being undetectable about 2 mm from the lesion. The depolarization reached a peak value (40 mV at 0.5 mm from the lesion) 3-5 min after injury and was followed by a gradual repolarization which was complete in about 60 min. A second lesion evoked the same changes, but under conditions of a low calcium solution, there was no recovery in the potential. The rate of indicator penetration reached a peak value (20μm/min) when depolarization was near maximal, declined as the membrane repolarized and became negligible in about 50 min. Conversely, the transected striated muscle fibers of the guinea-pig diaphragm remained depolarized for more than 1 hr after injury. These observations suggest that the healing-over process is a property of the striated muscle fibers of the guinea-pig cremaster and may tentatively be ascribed to the development of a calcium-dependent diffusion barrier (of unknown nature) in the area of the injury.