Neuronal Trophic Function

Abstract

THE neuronal trophic influence on developing skeletal muscle fibers has been the subject of speculation in attempts to understand the pathogenesis of certain congenital neuromuscular disorders, such as infantile spinal muscular atrophy¹ and central core disease.² Because direct evidence on the dynamics of the nerve-muscle relationship is impossible to obtain in the human, experimental animals must be used. The sequence of histochemical changes from a mixed to a uniform pattern in the guinea pig soleus extrafusal muscle fibers from the 50th gestational day to 6 weeks postnatal age and prevention of that change by neonatal denervation are described in this study. The developing soleus muscle of the rat and cat was also studied. Methods On fresh, frozen, cryostat sections of 10μ thickness, a battery of ten histochemical reactions was used as detailed elsewhere.^3,4 Our preferred technique for histochemical fiber typing is the myofibrillar adenosine triphosphatase (ATPase)