The over-all objective of this project is to identify neurotrophic influences upon protein synthesis in the interrelationship between the motor neuron and its consequent muscle cell. It is thought that neurotrophic substance(s) which are synthesized in the cell body of the neuron and carried by axoplasmic transport to the contiguous muscle cell may play a role in the regulation of protein synthesis in the target cell. This investigation proposes to explore the relevance of the turnover of regulatory proteins and RNA in skeletal muscle nuclei to neurotrophism. Elucidation of the molecular nature of trophic nerve functions has potential clinical importance to neurology in the treatment of neuromuscular disorders due to nerve trauma or hereditary disease.