Nerve-muscle interaction: changes in the cellular organization of a skeletal muscle upon denervation

The alterations in the organization of lumbrical muscle of the rat have been investigated following denervation, with emphasis on the structure of cytoplasmic constituents, sarcolemma in the synaptic and non-synaptic regions and acetylcholinesterase activity. The appearance of 15--18 nm intramenbranous particles in the non-synaptic sarcolemma is thought to be related to the known acetylcholine extrajunctional sensitivity which is manifested after denervation. The acetylcholinesterase activity is greatly reduced in the synaptic region in the denervated muscle. These changes are discussed in relation to the known physiological and biochemical data.