Examination of variables of aldehyde fixation that may affect the shape of agranular synaptic vesicles has revealed that even brief storage of aldehyde-perfused nervous tissue pieces in cacodylate buffer, prior to hardening in osmium tetroxide, has an unusually severe flattening effect on agranular vesicles of a particular type. These are the vesicles of peripheral cholinergic axon endings, and of certain central synaptic bulbs. Types of synaptic bulbs can now be further defined on the basis of shape of agranular synaptic vesicles under controlled conditions of aldehyde fixation. Previously described "S" bulbs in the spinal cord contain uniformly spheroid vesicles, which are wholly resistant to flattening. Previously described "F" bulbs contain somewhat smaller agranular vesicles that are flattened after aldehyde fixation, even when this is followed by prompt hardening in osmium tetroxide solution. A third type, previously characterized as having irregularly round agranular vesicles after the above treatment, contains only severely flattened vesicles when the osmium tetroxide hardening is preceded by even a brief wash with sodium cacodylate buffer containing sucrose. Moreover, the "third" type is characteristic of all cholinergic peripheral axon endings examined, as well as the large axosomatic ("L") synaptic bulbs of the spinal cord.
Article| January 01 1970
AN ELECTRON MICROSCOPIC CHARACTERIZATION OF CLASSES OF SYNAPTIC VESICLES BY MEANS OF CONTROLLED ALDEHYDE FIXATION
From the Department of Anatomy, The Johns Hopkins University School of Medicine, Baltimore Maryland 21205
Received: June 19 1969
Revision Received: August 28 1969
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1970 by The Rockefeller University Press.
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David Bodian; AN ELECTRON MICROSCOPIC CHARACTERIZATION OF CLASSES OF SYNAPTIC VESICLES BY MEANS OF CONTROLLED ALDEHYDE FIXATION . J Cell Biol 1 January 1970; 44 (1): 115–124. doi: https://doi.org/10.1083/jcb.44.1.115
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