[ULTRASTRUCTURE OF MOTOR NEURONS AND SYNAPSES IN THE OCULOMOTOR NERVE NUCLEI IN MICE]

Motor neuron and synapse ultrastructure in the somatic area of oculomotor nerve nuclei (cranial nerve III nuclei) was studied in C57 Black/6 mice. It was shown that that axodendritic and axosomatic synapses were characterized by rounded subjunctional bodies, located at the postsynaptic side of the synaptic contact at some distance from postsynaptic density. At the site of the subjunctional densities, the synaptic gap was expanded to 30 µm. In the same synapse, the synaptic gap could be reduced twice or more. Axosomatic and axodendritic synapses occured on spines. On the soma and dendrites of motoneurons, en passant type of synapses were found. No gap junctions were observed.