An in vivo nerve-muscle preparation of the dystrophic strain New Hampshire chicken will be developed. The functional properties of the pre- and postsynaptic motor nerve terminal will be investigated. The postsynaptic membrane will be studied using extracellular and intracellular recording techniques, which will also yield indirect evidence of presynaptic activity. The presynaptic response will be examined by recording antidromic activity at the ventral root. The pharmacological response of the neuromuscular junction will be characterized electrophysiologically and on the basis of the contractile response. In the course of these observations characterizing the neural involvement in muscular dystrophy, a specific hypothesis for a motor terminal dysfunction and a postulated therapy for it, will be tested.