Abstract
Motor nerve section brings about many changes in a denervated muscle. The first which can be readily detected is a fall in resting membrane potential. This was noted by Albuquerque et al. when the deep peroneal nerves of rats were sectioned at the entrance to the extensor digitorum muscle, the time course depending on the intramuscular length of the degenerating nerve fiber.
Similar results can be obtained in vitro using the rat phrenic nerve hemidiaphragm preparation and that the rapid fall in resting membrane potential upon denervation can be prevented by means which suggest the existence of a soluble trophic factor.