ISSN:
0002-9106
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The non-primary input to the soma of the principal cells of the rostral anteroventral cochlear nucleus (AVCN) of the guinea pig was defined by correlating data from freeze-fractured and thin-sectioned specimens. The principal cells receive three types of non-primary terminals in addition to a single end bulb from the ascending branch of the auditory nerve. The first, the O-boutons are irregularly shaped, medium-sized boutons, containing oval synaptic vesicles. These cover about 13% of the soma and each makes from one to three crescent-shaped axosomatic junctions. Paramembranous dense material is distributed symmetrically between the pre- and postsynaptic junctional membranes. The second, the F-bouton, is a small, ovate bouton which occurs either singly or in small clusters and covers about 5% of the soma. This bouton, containing flattened synaptic vesicles, has a single, oval synaptic junction lined by thin, paramembranous densities distributed symmetrically between the pre-and postsynaptic membranes. The third, the SR-bouton, is a medium-sized bouton containing small, round synaptic vesicles. These boutons cover about 4% of the soma, but more frequently contact dendrites in the neuropil. The junctional region of the bouton is poorly defined. Small tufts of dense material symmetrically line the cytoplasmic surfaces of the pre- and postsynaptic membranes along scattered, narrow undulations of the apposition. In freeze-fracture replicas, several narrow troughs on the cytoplasmic leaflet frequently have a higher density of large intramembranous particles than adjacent membrane and may represent a diffusely organized active zone. No specializations are found on either leaflet of the postsynaptic plasmalemma opposite the non-primary boutons. Correlation of the measurements from thin-sectioned and freeze-fractured material suggests that the oval, flattened, and small round vesiclecontaining boutons occur on the somata of the principal cells in a ratio of 6:3:1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aja.1001530402
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