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Junctional ultrastructure in isolated synaptic membranes.

A I Matus·B B Walters·D H Jones
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Abstract

The ultrastructure of synaptic junctions in whole brain tissue and isolated synaptic membranes has been compared. Type 1 junctions are present in the isolated membranes,readily identified by the presence of dense-staining material associated with the postsynaptic membrane, but the dense projections present at the presynaptic membrane in intact tissue are absent. Type 2 junctions are not easily recognized because of the absence of prominent junctional densities, but apposed membranes with the appearance of type 2 junctions are seen in isolated membrane preparations. Junctions without dense-staining material are also seen among SYNAPtosomes and survive the hypotonic conditions used during isolation of the membranes. It thus seems probable that both type 1 and 2 junctions are present in isolated synaptic membrane preparations. In type 1 junctions after isolation,the postsynaptic thickening and cleft substance are together seen to be composed of an array of 200 A dense-staining subunits spanning the postsynaptic unit membrane. The relationship of this structure to the ultrastructure of the cleft substance and postsynapticthickening in intact tissue is discussed.

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AnimalsBrainCell FractionationMicroscopy, ElectronRatsSynapsesSynaptic MembranesSynaptosomesComparative StudyJournal Article

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A I Matus, B B Walters, D H Jones. 1975. Junctional ultrastructure in isolated synaptic membranes.. https://doi.org/10.1007/bf01102118

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