Release of calcium into the myofibrillar space in response to active shortening of striated muscle
(2017) In Acta Physiologica 221(2). p.142-148- Abstract
Aim: The study was undertaken to explore whether shortening of striated muscle during activity is associated with release of bound Ca2+ into the myofibrillar space as has previously been proposed in order to explain the depressant effect of active shortening. Methods: The experiments were carried out on single muscle fibres isolated from the anterior tibialis muscle of Rana temporaria. The fibres were loaded with the calcium sensitive indicator Fluo-3. The fibres, stimulated to produce a partially fused isometric tetanus, were subjected to a shortening ramp or, alternatively, to a stretch ramp during activity while force, fibre length, sarcomere length and the Fluo-3 signal were recorded. Results: A shortening ramp performed... (More)
Aim: The study was undertaken to explore whether shortening of striated muscle during activity is associated with release of bound Ca2+ into the myofibrillar space as has previously been proposed in order to explain the depressant effect of active shortening. Methods: The experiments were carried out on single muscle fibres isolated from the anterior tibialis muscle of Rana temporaria. The fibres were loaded with the calcium sensitive indicator Fluo-3. The fibres, stimulated to produce a partially fused isometric tetanus, were subjected to a shortening ramp or, alternatively, to a stretch ramp during activity while force, fibre length, sarcomere length and the Fluo-3 signal were recorded. Results: A shortening ramp performed during a partially fused tetanus caused an increase in the myofibrillar free calcium concentration and produced, simultaneously, a decrease in active force. The isometric force recovered gradually after the shortening ramp, while the intracellular Ca2+ concentration stayed above the control level during the remainder of the stimulation period. A stretch ramp applied during a partially fused tetanus caused a considerably smaller change in the myofibrillar Ca2+ concentration. Conclusion: The results provide evidence that the myosin cross-bridges interact with the calcium binding sites on the thin filaments during active shortening, causing sustained release of calcium and reduced contractile strength.
(Less)
- author
- Edman, K. A.P. LU and Caputo, C
- organization
- publishing date
- 2017-04-11
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Muscle fibre, Myofibrillar calcium release, Striated muscle
- in
- Acta Physiologica
- volume
- 221
- issue
- 2
- pages
- 142 - 148
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:28317338
- wos:000410785000010
- scopus:85017572661
- ISSN
- 1748-1716
- DOI
- 10.1111/apha.12876
- language
- English
- LU publication?
- yes
- id
- a63c2f6b-1988-4400-8724-9ca9d274da7a
- date added to LUP
- 2017-05-08 15:59:45
- date last changed
- 2024-03-17 13:29:44
@article{a63c2f6b-1988-4400-8724-9ca9d274da7a,
abstract = {{<p>Aim: The study was undertaken to explore whether shortening of striated muscle during activity is associated with release of bound Ca<sup>2+</sup> into the myofibrillar space as has previously been proposed in order to explain the depressant effect of active shortening. Methods: The experiments were carried out on single muscle fibres isolated from the anterior tibialis muscle of Rana temporaria. The fibres were loaded with the calcium sensitive indicator Fluo-3. The fibres, stimulated to produce a partially fused isometric tetanus, were subjected to a shortening ramp or, alternatively, to a stretch ramp during activity while force, fibre length, sarcomere length and the Fluo-3 signal were recorded. Results: A shortening ramp performed during a partially fused tetanus caused an increase in the myofibrillar free calcium concentration and produced, simultaneously, a decrease in active force. The isometric force recovered gradually after the shortening ramp, while the intracellular Ca<sup>2+</sup> concentration stayed above the control level during the remainder of the stimulation period. A stretch ramp applied during a partially fused tetanus caused a considerably smaller change in the myofibrillar Ca<sup>2+</sup> concentration. Conclusion: The results provide evidence that the myosin cross-bridges interact with the calcium binding sites on the thin filaments during active shortening, causing sustained release of calcium and reduced contractile strength.</p>}},
author = {{Edman, K. A.P. and Caputo, C}},
issn = {{1748-1716}},
keywords = {{Muscle fibre; Myofibrillar calcium release; Striated muscle}},
language = {{eng}},
month = {{04}},
number = {{2}},
pages = {{142--148}},
publisher = {{Wiley-Blackwell}},
series = {{Acta Physiologica}},
title = {{Release of calcium into the myofibrillar space in response to active shortening of striated muscle}},
url = {{http://dx.doi.org/10.1111/apha.12876}},
doi = {{10.1111/apha.12876}},
volume = {{221}},
year = {{2017}},
}