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Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction

The distribution of two synaptic vesicle-specific phosphoproteins, synaptophysin and synapsin I, during intense quantal secretion was studied by applying an immunogold labeling technique to ultrathin frozen sections. In nerve-muscle preparations treated for 1 h with a low dose of alpha-latrotoxin in...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1990
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2116013/
https://www.ncbi.nlm.nih.gov/pubmed/1967610
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description The distribution of two synaptic vesicle-specific phosphoproteins, synaptophysin and synapsin I, during intense quantal secretion was studied by applying an immunogold labeling technique to ultrathin frozen sections. In nerve-muscle preparations treated for 1 h with a low dose of alpha-latrotoxin in the absence of extracellular Ca2+ (a condition under which nerve terminals are depleted of both quanta of neurotransmitter and synaptic vesicles), the immunolabeling for both proteins was distributed along the axolemma. These findings indicate that, in the presence of a block of endocytosis, exocytosis leads to the permanent incorporation of the synaptic vesicle membrane into the axolemma and suggest that, under this condition, at least some of the synapsin I molecules remain associated with the vesicle membrane after fusion. When the same dose of alpha-latrotoxin was applied in the presence of extracellular Ca2+, the immunoreactivity patterns resembled those obtained in resting preparations: immunogold particles were selectively associated with the membrane of synaptic vesicles, whereas the axolemma was virtually unlabeled. Under this condition an active recycling of both quanta of neurotransmitter and vesicles operates. These findings indicate that the retrieval of components of the synaptic vesicle membrane is an efficient process that does not involve extensive intermixing between molecular components of the vesicle and plasma membrane, and show that synaptic vesicles that are rapidly recycling still have the bulk of synapsin I associated with their membrane.
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spelling pubmed-21160132008-05-01 Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction J Cell Biol Articles The distribution of two synaptic vesicle-specific phosphoproteins, synaptophysin and synapsin I, during intense quantal secretion was studied by applying an immunogold labeling technique to ultrathin frozen sections. In nerve-muscle preparations treated for 1 h with a low dose of alpha-latrotoxin in the absence of extracellular Ca2+ (a condition under which nerve terminals are depleted of both quanta of neurotransmitter and synaptic vesicles), the immunolabeling for both proteins was distributed along the axolemma. These findings indicate that, in the presence of a block of endocytosis, exocytosis leads to the permanent incorporation of the synaptic vesicle membrane into the axolemma and suggest that, under this condition, at least some of the synapsin I molecules remain associated with the vesicle membrane after fusion. When the same dose of alpha-latrotoxin was applied in the presence of extracellular Ca2+, the immunoreactivity patterns resembled those obtained in resting preparations: immunogold particles were selectively associated with the membrane of synaptic vesicles, whereas the axolemma was virtually unlabeled. Under this condition an active recycling of both quanta of neurotransmitter and vesicles operates. These findings indicate that the retrieval of components of the synaptic vesicle membrane is an efficient process that does not involve extensive intermixing between molecular components of the vesicle and plasma membrane, and show that synaptic vesicles that are rapidly recycling still have the bulk of synapsin I associated with their membrane. The Rockefeller University Press 1990-02-01 /pmc/articles/PMC2116013/ /pubmed/1967610 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title_full Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title_fullStr Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title_full_unstemmed Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title_short Redistribution of synaptophysin and synapsin I during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
title_sort redistribution of synaptophysin and synapsin i during alpha-latrotoxin- induced release of neurotransmitter at the neuromuscular junction
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2116013/
https://www.ncbi.nlm.nih.gov/pubmed/1967610