Transfer of synaptic vesicle antigens to the presynaptic plasma membrane during exocytosis.
AUTOR(ES)
von Wedel, R J
RESUMO
We have utilized immunofluorescence techniques to look for synaptic vesicle antigens on the plasma membrane of resting and active nerve terminals. Rabbit antiserum was raised against purified cholinergic synaptic vesicles from the electric organ of Narcine brasiliensis, a marine electric ray. Antibodies to synaptic vesicles were shown to bind selectively to nerve terminals in cryostat sections of frog nerve-muscle preparations. Binding was demonstrated indirectly by using fluorescein-labeled goat anti-rabbit antibodies. Structures in cross sections that bound antiserum were identified as nerve terminals because of their size, shape, and position and because they coincided with sites that bound rhodamine-conjugated alpha-bungarotoxin and had acetylcholine esterase activity. Presumably, sectioning gave antibodies access to binding sites within the nerve terminal. However, when antibodies to synaptic vesicles were added to the bathing medium of intact neuromuscular preparations prior to sectioning, antibody binding was marginal or undetectable, suggesting that few vesicle antigens were normally accessible on the outer surface of resting nerve terminals. When intact preparations were stimulated to release their vesicular acetylcholine by the addition of 1 mM LaCl3, antibody binding to the intact nerve terminals became striking. These findings suggest that the synaptic vesicle membrane and the synaptic terminal plasma membrane differ in composition. They also provide further support for the exocytotic hypothesis of neurotransmitter release, which predicts that vesicle markers should be exposed on the outside of nerve terminals when vesicles fuse with the plasma membrane during stimulation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=319936Documentos Relacionados
- A synaptic vesicle antigen is restricted to the junctional region of the presynaptic plasma membrane.
- Gene variants and serum levels of synaptic vesicle and presynaptic plasma membrane proteins in alcohol dependence and their relationship with impulsivity and temperament
- Fluorescence Resonance Energy Transfer Detection of Synaptophysin I and Vesicle-associated Membrane Protein 2 Interactions during Exocytosis from Single Live Synapses
- Binding of the synaptic vesicle v-SNARE, synaptotagmin, to the plasma membrane t-SNARE, SNAP-25, can explain docked vesicles at neurotoxin-treated synapses
- Disassembly of the reconstituted synaptic vesicle membrane fusion complex in vitro.