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Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons
In mature neurons synaptic vesicles (SVs) undergo cycles of exo- endocytosis at synapses. It is currently unknown whether SV exocytosis and recycling occurs also in developing axons prior to synapse formation. To address this question, we have developed an immunocytochemical assay to reveal SV exo-e...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1992
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2289460/ https://www.ncbi.nlm.nih.gov/pubmed/1577861 |
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collection | PubMed |
description | In mature neurons synaptic vesicles (SVs) undergo cycles of exo- endocytosis at synapses. It is currently unknown whether SV exocytosis and recycling occurs also in developing axons prior to synapse formation. To address this question, we have developed an immunocytochemical assay to reveal SV exo-endocytosis in hippocampal neurons developing in culture. In this assay antibodies directed against the lumenal domain of synaptotagmin I (Syt I), an intrinsic membrane protein of SVs, are used to reveal exposure of SV membranes at the cell surface. Addition of antibodies to the culture medium of living neurons for 1 hr at 37 degrees C resulted in their rapid and specific internalization by all neuronal processes and, particularly, by axons. Double immunofluorescence and electron microscopy immunocytochemistry indicated that the antibodies were retained within SVs in cell processes and underwent cycles of exo-endocytosis in parallel with SV membranes. In contrast, another endocytotic marker, wheat germ agglutinin, was rapidly cleared from the processes and transported to the cell body. Antibody-labeled SVs were still present in axons several days after antibody loading and became clustered at presynaptic sites in parallel with synaptogenesis. These results demonstrate that SVs undergo multiple cycles of exo-endocytosis in developing neuronal processes irrespective of the presence of synaptic contacts. |
format | Text |
id | pubmed-2289460 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1992 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22894602008-05-01 Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons J Cell Biol Articles In mature neurons synaptic vesicles (SVs) undergo cycles of exo- endocytosis at synapses. It is currently unknown whether SV exocytosis and recycling occurs also in developing axons prior to synapse formation. To address this question, we have developed an immunocytochemical assay to reveal SV exo-endocytosis in hippocampal neurons developing in culture. In this assay antibodies directed against the lumenal domain of synaptotagmin I (Syt I), an intrinsic membrane protein of SVs, are used to reveal exposure of SV membranes at the cell surface. Addition of antibodies to the culture medium of living neurons for 1 hr at 37 degrees C resulted in their rapid and specific internalization by all neuronal processes and, particularly, by axons. Double immunofluorescence and electron microscopy immunocytochemistry indicated that the antibodies were retained within SVs in cell processes and underwent cycles of exo-endocytosis in parallel with SV membranes. In contrast, another endocytotic marker, wheat germ agglutinin, was rapidly cleared from the processes and transported to the cell body. Antibody-labeled SVs were still present in axons several days after antibody loading and became clustered at presynaptic sites in parallel with synaptogenesis. These results demonstrate that SVs undergo multiple cycles of exo-endocytosis in developing neuronal processes irrespective of the presence of synaptic contacts. The Rockefeller University Press 1992-05-02 /pmc/articles/PMC2289460/ /pubmed/1577861 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 Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title | Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title_full | Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title_fullStr | Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title_full_unstemmed | Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title_short | Exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
title_sort | exo-endocytotic recycling of synaptic vesicles in developing processes of cultured hippocampal neurons |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2289460/ https://www.ncbi.nlm.nih.gov/pubmed/1577861 |