Electron Microscopic Observations on Terminal Boutons and Synaptic Structures in the Anterior Horn of the Spinal Cord in the Adult Cat

抄録

It is an indispensable need to explore the structure and function of the terminal bouton for the studies of the neuronal transmission mechanism in the central nervous system. As for the structure of the terminal bouton, light microscopy has given some idea to the structural variations of terminal boutons which might be related to the input complex of the anterior horn neuron as the final common path. From this point of view, Wyckoff and Young (1956) studied the organization of the anterior horn neuron by light microscope and by the aid of electron microscope. Unfortunately, however, they have failed to establish the details of the contacts between the neurons and the terminal boutons. It may probably be due to the limit of preparation techniques and also of resolution power of electron microscope at that time.
As mentioned previously in the introduction, present work is a summarized observation on the terminal boutons and synaptic structures in the ventro-lateral part of the anterior horn (C_6∼7) in the cat spinal cord. Almost all of the contacting types of the terminal boutons has been revealed in the previous OBSERVATION, though the statistical consideration has not been given yet. Compared with researches by Bodian (1966), Uchizono (1966), Conradi (1969) and so forth, it may be concluded as follows.