Synaptophysin (p38) immunolabelling at the mouse neuromuscular junction.
The synaptophysin (p38), a transmembrane glycoprotein of synaptic vesicles, has been used as a marker in order to study the membrane events that take place during transmitter release at the mouse neuromuscular junction (NMJ). p38 has been labelled by immunofluorescence using a monoclonal anti-p38 antibody and fluorescein-conjugated IgG on dissociated muscle fibres (biceps brachialis m.). Its localization has been compared to that of the acetylcholine (ACh) receptors labelled with rhodaminated alpha-bungarotoxin. A weak labelling was obtained in nerve-muscle preparations at rest only when the muscle fibres were permeabilized with Triton X-100. By contrast, an intense immunofluorescence of the NMJ was observed after an exhaustive ACh release induced by Cd2+ in Ca(2+)-free medium, which leads to a synaptic vesicle depletion and an increase in the membranous structures in nerve terminals. Treatment with Cd2+ in Ca(2+)-free solution leads to both synaptic vesicle depletion and p38 immunolabelling, which is in favour of synaptic vesicle fusion and incorporation into the axolemma.
Colasante
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C
Départment de Neurobiologie des Signaux Intercellulaires, URA CNRS-1488, Université Pierre et Marie Curie, Paris, France.
Brouard
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MO
Pécot-Dechavassine
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M
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D009132:Muscles / Q000166:cytology*; D009469:Neuromuscular Junction / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D016708:Synaptophysin / Q000032:analysis*
D016708:Synaptophysin; D002104:Cadmium; D000109:Acetylcholine