Ultrasonic investigations of the soleus muscle after space flight on the Biosputnik 936.

The study was aimed at quantitative and qualitative evaluation of the muscle fibres and the axonal endings of the neuromuscular junctions in the soleus muscle of animals after a space flight on Biosputnik 936. Ultrastructural morphometric studies of the muscle fibres demonstrated diminished volume of sarcomer and accumulation of glycogen granules. The mean number of mitochondrial profiles decreased. The investigations of the axonal endings of the neuromuscular junctions in the soleus muscle showed diminution of the mean number of synaptic vesicles and swelling of the mitochondria. This changing in the fibres and axonal endings we can interpret as the first step of degeneration.