[State of the muscle motor neuron apparatus in rats with limited mobility].

Neurohistochemical examinations of the motor nerve endings in the soleus and gastrochemius muscles of rats kept from 7 to 65 days under hypokinetic conditions were performed. The study of the soleus muscle revealed changes which resulted in the formation of the so-called target fibers and partial death of muscle fibers as well as changes in the nerve endings. These changes seemed to be destructive throughout the 7-15-hypokinetic day period and reparative during 30-65 hypokinetic days. The study of the gastrochemius muscle, where atrophic changes normally developed, did not demonstrate any structural changes in motor patches. It is suggested that disorders in the motor nerve endings of the soleus muscle are induced by circulation disturbances in the muscular tissue at early hypokinesia.