RESUMEN
The Nissl and Golgi staining methods and electron microscopy were u(?)o investigate the architecture of dorsal commissure nucleus (DCN) of the sacral spinal cord in cat. A morphologically specific nucleus could be identified in the medial part of the lamina Ⅵ of dorsal horn. The nucleus located beside the dorsal funiculus at the lumbar level and gradually moved toward the midline of the dorsal gray commissure in the ventromedial direction as the dorsal gray commissure enlarged at the segments S_(1-2) and two ellipsoid nuclei was formed at the two sides of the midline. A large triangular nucleus was gradually formed by fusion of the two nuclei at S_3-Co_1. Golgi stain positive neurons could be classified into three types: (1) small-triangular neurons (60%); (2) fusiform neurons (30%); (3) oval and irregular neurons (10%). The cell organells of most neurons were plentiful. The cell nucleus was irregular and often with deep invaginations. A large number of free ribosomes and saccules could be found in the canals formed by the nuclear invagination. There were axo-dentritic, axo-axonic, axo-somatic synaptic contacts in the DCN with percentages of 89%, 6%, and 5% respectively. The serial synapse, axo-spinous synapse and crest synapses could also be found.