Spontaneous Activity at Myoneural Junction in Dystrophic Muscle

Abstract

Introduction The strain 129 (dy dy) mice, obtained from the Jackson Memorial Laboratory, have been found to suffer from a genetically determined form of muscular dystrophy.¹⁹ This disease, in the mouse, has been characterized as a primary myopathy, mainly on the basis of a lack of nervous system lesions and a typical "dystrophic" pattern of peripheral involvement of the muscles. Question has arisen, however, concerning certain manifestations of this disease process implicating structures of the terminal innervation and myoneural junction. Evidence has been collected pointing to both functional and morphological involvement of the neuromuscular junction and its immediate environment. Baker and associates 4 have shown that dystrophic mice are hypersensitive to drugs that normally affect the neuromuscular junction; nerve muscle preparations from these animals are similarly hyperreactive to anticholinesterase drugs^2,3 suggesting disturbance in cholinergic mechanism. Indirect measurements of neuromuscular transmission have led us to conclude that an alteration