[Ultrastructure of the synaptic junctions between spinal motor neurons in the frog Rana ridibunda].

By means of light and electron microscopic observations, it has been demonstrated that on spinal motoneurones in the segments IX-X, in addition to synapses described earlier, there are electrotonic synaptic junctions of somato-somatic type and dendrosomatic gap junctions of circular type. The described synaptic junctions are considered as a structural base for electrical interaction between spinal motoneurones in the frog.