Synaptic organization of the medial acessory olivary nucleus of the cat

Light microscopically the morphological characteristic of neurons and ultrastructurally the synaptic organization of medial accessory olivary nucleus of cat was studied. Different types of chemically mediated as well as electric synapses were observed. The terminal boutons contain mainly clear synaptic vesicles, but small and large dense core vesicles are also available. In the neuropil of the nucleus characteristic glomeruli with central dendritic core were establish. The dendritic profiles were connected with numerous gap junctions and attachment plaques. The apposition without any synaptic specializations in a large area of the cell membrane of adjacent neurons was also observed. In some cases oval structures with size 450--650 A which we called submembraneous dense bodies were established under one of the apposite membranes.