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The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle
The subcellular distribution of the Ca(2+)-release channel/ryanodine receptor in adult rat papillary myofibers has been determined by immunofluorescence and immunoelectron microscopical studies using affinity purified antibodies against the ryanodine receptor. The receptor is confined to the sarcopl...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1993
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200068/ https://www.ncbi.nlm.nih.gov/pubmed/8381786 |
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collection | PubMed |
description | The subcellular distribution of the Ca(2+)-release channel/ryanodine receptor in adult rat papillary myofibers has been determined by immunofluorescence and immunoelectron microscopical studies using affinity purified antibodies against the ryanodine receptor. The receptor is confined to the sarcoplasmic reticulum (SR) where it is localized to interior and peripheral junctional SR and the corbular SR, but it is absent from the network SR where the SR-Ca(2+)-ATPase and phospholamban are densely distributed. Immunofluorescence labeling of sheep Purkinje fibers show that the ryanodine receptor is confined to discrete foci while the SR-Ca(2+)-ATPase is distributed in a continuous network-like structure present at the periphery as well as throughout interior regions of these myofibers. Because Purkinje fibers lack T- tubules, these results indicate that the ryanodine receptor is localized not only to the peripheral junctional SR but also to corbular SR densely distributed in interfibrillar spaces of the I-band regions. We have previously identified both corbular SR and junctional SR in cardiac muscle as potential Ca(2+)-storage/Ca(2+)-release sites by demonstrating that the Ca2+ binding protein calsequestrin and calcium are very densely distributed in these two specialized domains of cardiac SR in situ. The results presented here provide strong evidence in support of the hypothesis that corbular SR is indeed a site of Ca(2+)-induced Ca2+ release via the ryanodine receptor during excitation contraction coupling in cardiac muscle. Furthermore, these results indicate that the function of the cardiac Ca(2+)-release channel/ryanodine receptor is not confined to junctional complexes between SR and the sarcolemma. |
format | Text |
id | pubmed-2200068 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1993 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22000682008-05-01 The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle J Cell Biol Articles The subcellular distribution of the Ca(2+)-release channel/ryanodine receptor in adult rat papillary myofibers has been determined by immunofluorescence and immunoelectron microscopical studies using affinity purified antibodies against the ryanodine receptor. The receptor is confined to the sarcoplasmic reticulum (SR) where it is localized to interior and peripheral junctional SR and the corbular SR, but it is absent from the network SR where the SR-Ca(2+)-ATPase and phospholamban are densely distributed. Immunofluorescence labeling of sheep Purkinje fibers show that the ryanodine receptor is confined to discrete foci while the SR-Ca(2+)-ATPase is distributed in a continuous network-like structure present at the periphery as well as throughout interior regions of these myofibers. Because Purkinje fibers lack T- tubules, these results indicate that the ryanodine receptor is localized not only to the peripheral junctional SR but also to corbular SR densely distributed in interfibrillar spaces of the I-band regions. We have previously identified both corbular SR and junctional SR in cardiac muscle as potential Ca(2+)-storage/Ca(2+)-release sites by demonstrating that the Ca2+ binding protein calsequestrin and calcium are very densely distributed in these two specialized domains of cardiac SR in situ. The results presented here provide strong evidence in support of the hypothesis that corbular SR is indeed a site of Ca(2+)-induced Ca2+ release via the ryanodine receptor during excitation contraction coupling in cardiac muscle. Furthermore, these results indicate that the function of the cardiac Ca(2+)-release channel/ryanodine receptor is not confined to junctional complexes between SR and the sarcolemma. The Rockefeller University Press 1993-02-02 /pmc/articles/PMC2200068/ /pubmed/8381786 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 The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title | The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title_full | The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title_fullStr | The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title_full_unstemmed | The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title_short | The Ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
title_sort | ca2+-release channel/ryanodine receptor is localized in junctional and corbular sarcoplasmic reticulum in cardiac muscle |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2200068/ https://www.ncbi.nlm.nih.gov/pubmed/8381786 |