[An experimental study on direct nerve implantation into denervated muscle--the functional recovery and the site of implantation].

: The functional recovery of the newly formed endplates in the muscle reinnervated by direct neurotization was studied grossly, electrophysiologically and histologically in the anterior tibialis muscle of rats. The proximal stump of the tibial nerve was severed at the ankle level and was embedded at the level of distal one fifth of the muscle where no endplates were detected just after denervation of the muscle. Histologically, the accumulations of acetylcholinesterase activity were detected 4 weeks after neurotization. Electrophysiological study using a multi-channel electrode revealed the two-directional propagation of action potentials 8 weeks after neurotization, and the propagation started from no other sites than the nerve-implantation. The muscle tension revealed 42% of the contralateral muscle 52 weeks after neurotization. These results concluded that the function of the newly formed endplates spread throughout the muscle and it was lasting.