title: Synaptic organization of the nucleus rotundus in some teleosts.
abstract: Synaptic organization of the nucleus rotundus was studied with the electron microscope in three teleost species belonging to the same order. In spite of the different histological organization (non-laminated, incompletely laminated, and laminated), the same kinds of axon terminals (S and F) are observed in all species. A fibrous layer which is clearly formed only in the laminated nucleus is composed of F1 terminals and dendrites from a layer of small cells. The same kind of synapses formed between F1 terminals and dendrites of small cells are also found among glomeruli in the non-laminated and incompletely laminated nuclei. The main constituents of glomeruli are S and F2 terminals and dendrites of large cells in the non-laminated and incompletely laminated nuclei, and are S terminals and star-like structures which correspond to the tips of the dendrites of large cells in the laminated nucleus. The star-like structure contains numerous mitochondria and clusters of small polymorphic vesicles. Some of the vesicles aggregate at thickened cell membranes of the structure as in presynaptic dendrites.
mesh_terms: D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D002462:Cell Membrane / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D005399:Fishes / Q000033:anatomy & histology*; D008928:Mitochondria / Q000648:ultrastructure; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure*