ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE
Fresh taenia coli and chicken gizzard smooth muscle were studied in the contracted and relaxed states. Thick and thin filaments were observed in certain (but not all) cells fixed in contraction. Relaxed smooth muscle contained only thin filaments. Several other morphological differences were observ...
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| Format: | Online |
| Language: | English |
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The Rockefeller University Press
1969
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2107698/ |
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pubmed-2107698 |
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oai_dc |
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pubmed-21076982008-05-01 ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE Kelly, Robert E. Rice, Robert V. Article Fresh taenia coli and chicken gizzard smooth muscle were studied in the contracted and relaxed states. Thick and thin filaments were observed in certain (but not all) cells fixed in contraction. Relaxed smooth muscle contained only thin filaments. Several other morphological differences were observed between contracted and relaxed smooth muscle. The nuclear chromatin is clumped in contraction and evenly dispersed in the relaxed state. The sarcolemma is more highly vesiculated in contraction than in relaxation. In contraction, the sarcoplasm also appears more electron opaque. Over-all morphological differences between cells fixed in isometric and in unloaded contraction were also noticeable. The results suggest a sliding filament mechanism of smooth muscle contraction; however, in smooth muscle, unlike striated muscle, the thick filaments appear to be in a highly labile condition in the contractile process. The relation between contraction and a possible change in pH is also discussed. The Rockefeller University Press 1969-09-01 /pmc/articles/PMC2107698/ /pubmed/5801426 Text en Copyright © 1969 by The Rockefeller University Press. 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 |
| format |
Online |
| author |
Kelly, Robert E. Rice, Robert V. |
| spellingShingle |
Kelly, Robert E. Rice, Robert V. ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| author_facet |
Kelly, Robert E. Rice, Robert V. |
| author_sort |
Kelly, Robert E. |
| title |
ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| title_short |
ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| title_full |
ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| title_fullStr |
ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| title_full_unstemmed |
ULTRASTRUCTURAL STUDIES ON THE CONTRACTILE MECHANISM OF SMOOTH MUSCLE |
| title_sort |
ultrastructural studies on the contractile mechanism of smooth muscle |
| description |
Fresh taenia coli and chicken gizzard smooth muscle were studied in the contracted and relaxed states. Thick and thin filaments were observed in certain (but not all) cells fixed in contraction. Relaxed smooth muscle contained only thin filaments. Several other morphological differences were observed between contracted and relaxed smooth muscle. The nuclear chromatin is clumped in contraction and evenly dispersed in the relaxed state. The sarcolemma is more highly vesiculated in contraction than in relaxation. In contraction, the sarcoplasm also appears more electron opaque. Over-all morphological differences between cells fixed in isometric and in unloaded contraction were also noticeable. The results suggest a sliding filament mechanism of smooth muscle contraction; however, in smooth muscle, unlike striated muscle, the thick filaments appear to be in a highly labile condition in the contractile process. The relation between contraction and a possible change in pH is also discussed. |
| publisher |
The Rockefeller University Press |
| publishDate |
1969 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2107698/ |
| _version_ |
1611409654091350016 |