Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability

A new technique utilizing the squid giant nerve fiber has been developed which permits direct examination of the inner face of the axolemma by scanning electron microscopy. The axoplasm was removed sequentially in a 15-mm long segment of the fiber by intracellular perfusion with a solution of KF, KC...

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Format: Online
Language:English
Published: The Rockefeller University Press 1978
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110117/
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spelling pubmed-21101172008-05-01 Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability Articles A new technique utilizing the squid giant nerve fiber has been developed which permits direct examination of the inner face of the axolemma by scanning electron microscopy. The axoplasm was removed sequentially in a 15-mm long segment of the fiber by intracellular perfusion with a solution of KF, KCl, Ca++-containing seawater, or with pronase. The action potential of the fibers was monitored during these treatments. After brief prefixation in 1% paraformaldehyde and 1% glutaraldehyde, the perfused segment was opened by a lne could be related to information on the detailed morphology of the cytoplasmic face of the axolemma and the ectoplasm. The results obtained by scanning electron microscopy were further substantiated by transmission electron microscopy of thin sections. In addition, living axons were studied with polarized light during axoplasm removal, and the identification of actin by heavy meromyosin labeling and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis was accomplished. These observations demonstrate that a three-dimensional network of interwoven filaments, consisting partly of an actinlike protein, is firmly attached to the axolemma. The axoplasmic face of fibers in which the filaments have been removed partially after perfusion with pronase displays smooth membranous blebs and large profiles which sppose the axolemma. In fibers where the excitability has been suppressed by pronase perfusion, approximately one-third of the inner face of the axolemma in the perfusion zone is free of filaments. It is hypothesized that the attachment of axoplasm filaments to the axolemma may have a role in the maintenance of the normal morphology of the axolemma, and, thus, in some aspect of excitability. The Rockefeller University Press 1978-08-01 /pmc/articles/PMC2110117/ /pubmed/690181 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/).
repository_type Open Access Journal
institution_category Foreign Institution
institution US National Center for Biotechnology Information
building NCBI PubMed
collection Online Access
language English
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title Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
spellingShingle Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
title_short Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
title_full Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
title_fullStr Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
title_full_unstemmed Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability
title_sort subaxolemmal filamentous network in the giant nerve fiber of the squid (loligo pealei l.) and its possible role in excitability
description A new technique utilizing the squid giant nerve fiber has been developed which permits direct examination of the inner face of the axolemma by scanning electron microscopy. The axoplasm was removed sequentially in a 15-mm long segment of the fiber by intracellular perfusion with a solution of KF, KCl, Ca++-containing seawater, or with pronase. The action potential of the fibers was monitored during these treatments. After brief prefixation in 1% paraformaldehyde and 1% glutaraldehyde, the perfused segment was opened by a lne could be related to information on the detailed morphology of the cytoplasmic face of the axolemma and the ectoplasm. The results obtained by scanning electron microscopy were further substantiated by transmission electron microscopy of thin sections. In addition, living axons were studied with polarized light during axoplasm removal, and the identification of actin by heavy meromyosin labeling and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis was accomplished. These observations demonstrate that a three-dimensional network of interwoven filaments, consisting partly of an actinlike protein, is firmly attached to the axolemma. The axoplasmic face of fibers in which the filaments have been removed partially after perfusion with pronase displays smooth membranous blebs and large profiles which sppose the axolemma. In fibers where the excitability has been suppressed by pronase perfusion, approximately one-third of the inner face of the axolemma in the perfusion zone is free of filaments. It is hypothesized that the attachment of axoplasm filaments to the axolemma may have a role in the maintenance of the normal morphology of the axolemma, and, thus, in some aspect of excitability.
publisher The Rockefeller University Press
publishDate 1978
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110117/
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