JUNCTIONAL FORM OF ACETYLCHOLINESTERASE RESTORED AT NERVE-FREE ENDPLATES

Rat soleus muscles were ectopically innervated by implanting a foreign nerve in an endplate-free region of muscle and, 2-3 weeks later, cutting the original nerve. The junctional, 16 S form of acetylcholinesterase (AChE) and focal staining for AChE disappeared from the old endplate region within a few days after denervation. In muscles with an ectopic nerve, but not in paired control muscles, 16 S AChE and focal staining were restored in the old endplate region 1-2 weeks after denervation even though nerve fibers could not be detected in that region. These results suggest that the nerve exerts a local effect, specifying the site at which junctional AChE appears, and a nonlocal effect, perhaps mediated by muscle activity, regulating the amount of junctional AChE. © 1979.