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Comparative study of neuronal and glial gap‐junctions in crayfish nerve cords
Author(s) -
Bosch Elizabeth
Publication year - 1989
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.902850307
Subject(s) - gap junction , biology , cytoskeleton , neuroscience , cell junction , synaptic vesicle , biophysics , vesicle , microbiology and biotechnology , intracellular , cell , membrane , biochemistry
Electrical synapses (neuronal gap‐junctions) and glial gap‐junctions were compared by using thin sectioning, freeze fracturing, and negative staining techniques. Neuronal and glial gap‐junctions differed in the length of the extracellular domains of the channels, in the presence of a cytoskeleton associated to neuronal gap‐junctions, and in their unit cell dimenstions. The difference in length of the channels and the fact that both glial and neuronal gap‐junctions had the same particle diameter suggest that the proteins forming glial and neuronal gap‐junctions might have different molecular weights. The cytoskeleton associated to neuronal gap‐junctions consisted of a beaded layer of densities located parallel to the membrane in the synaptic regions. Synaptic vesicles associated to neuronal gap‐junctions were attached to this cytoskeleton, which was in turn anchored to the synptic membrane through densities about 20 nm apart, a spacing similar to the neuronal unit cell dimension. These results suggest that the cytoskeleton might be responsible for the association of vesicles to neuronal gap‐junctions and for maintaining the crystalline appearance of neuronal gap‐junctions in situ.