[Development of neuromuscular synapse in the skeletal muscle after chemical desympathization].

The purpose of this investigation was the study of cholinesterase (ChE)-positive zones of neuromuscular synapse (NMS) in gastrocnemius and plantaris muscles of albino rats after guanethidine sympathectomy. Qualitative and morphometric characteristics of ChE-positive zones were studied, which were demonstrated using a modified thioacetic acid method in 72 control and experimental animals aged from 5 days to 3 months. It was found that in both gastrocnemius and plantaris muscles the growth of muscle fiber diameter and section area in the region of NMS was delayed after desympathization. In gastrocnemius muscle, smaller fiber diameter persisited up to the age of 3 months, while in plantaris muscle it was larger than in control animals of the same age. The differences in dimensional parameters of NMS sections were leveled off by the age of 3 months because of their accelerated growth. Desympathization resulted in the premature appearance of dystrophic changes in MNS region as compared to those developing in control animals, in which they are the features of involution processes.