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Accumulation of synaptic vesicle proteins and cytoskeletal specializations at the peripheral node of Ranvier
Author(s) -
Zimmermann Herbert
Publication year - 1996
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/(sici)1097-0029(19960801)34:5<462::aid-jemt6>3.0.co;2-o
Subject(s) - node of ranvier , cytoskeleton , microbiology and biotechnology , chemistry , biology , biophysics , neuroscience , cell , biochemistry , myelin , central nervous system
Nodes of Ranvier of peripheral nerve fibres represent repetitive physiological axon constrictions. The nodal attenuation of the axon cylinder is expected to facilitate eliciting axon potentials. But as revealed by immunocytochemical analysis of synaptic vesicle proteins such as SV2 and synaptophysin, nodes are also sites of accumulation of the synaptic vesicle membrane compartment. Results from our studies and other laboratories suggest that the local nodal retardation of the axonally transported synaptic vesicle membrane compartment serves membrane processing and/or turnover. Nodes of Ranvier as well as incisures of Schmidt‐Lanterman are rich in filamentous actin and can easily be depicted by fluoresceinated phalloidin. At the node and paranode phalloidin fluorescence appears to be mainly associated with the Schwann cell compartment. Immunofluorescence demonstrates that this compartment also contains myosin and spectrin. The nodal contents in actin and myosin may be effective in actively constricting the axon cylinder at both the node of Ranvier and the Schmidt‐Lanterman incisures. This hypothesis is discussed in the light of the nodal cytoskeletal specializations of the axon cylinder and the ensheathing Schwann cell. © 1996 Wiley‐Liss, Inc.