E–C coupling and contractile characteristics of mechanically skinned single fibres from young rats during rapid growth and maturation

E–C coupling and contractile characteristics of mechanically skinned single fibres from young... The postnatal growth of rats involves a developmental phase (0 to ∼3 weeks), a rapid growth phase (∼3 to ∼10 weeks), and a slower maturation phase (∼10 weeks+). In this study, we investigated the age-related changes in excitation–contraction (E–C) coupling characteristics of mammalian skeletal muscle, during rapid growth (4–10 weeks) and maturation (10–21 weeks) phases, using single, mechanically skinned fibres from rat extensor digitorum longus (EDL) muscle. Fibres from rats aged 4 and 8 weeks produced lower maximum T-system depolarization-induced force responses and fewer T-system depolarization-induced force responses to 75% run-down than those produced by fibres from rats aged 10 weeks and older. The sensitivity of the contractile apparatus to Ca2+ in fibres from 4-week rats was significantly higher than that in fibres from 10-week rats; however, the maximum Ca2+-activated force per skinned fibre cross-sectional area (specific force) developed by fibres from 4-week rats was on average ∼44% lower than the values obtained for all the other age groups. In agreement with the age difference in specific force, the MHC content of EDL muscles from 4-week rats was ∼29% lower than that of 10-week rats. Thus, mechanically skinned fibres from rats undergoing rapid growth are less responsive to T-system depolarization and maximal Ca2+ activation than fibres from rats at the later stage of maturation or adult rats. These results suggest that during the rapid growth phase in rats, the structure and function of elements involved in E–C coupling in fast-twitch skeletal muscle continue to undergo significant changes. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Pflügers Archiv European Journal of Physiologyl of Physiology Springer Journals

E–C coupling and contractile characteristics of mechanically skinned single fibres from young rats during rapid growth and maturation

Loading next page...
 
/lp/springer-journal/e-c-coupling-and-contractile-characteristics-of-mechanically-skinned-DMttfA7pmn
Publisher
Springer Journals
Copyright
Copyright © 2008 by Springer-Verlag
Subject
Biomedicine; Human Physiology
ISSN
0031-6768
eISSN
1432-2013
DOI
10.1007/s00424-008-0474-9
pmid
18322696
Publisher site
See Article on Publisher Site

Abstract

The postnatal growth of rats involves a developmental phase (0 to ∼3 weeks), a rapid growth phase (∼3 to ∼10 weeks), and a slower maturation phase (∼10 weeks+). In this study, we investigated the age-related changes in excitation–contraction (E–C) coupling characteristics of mammalian skeletal muscle, during rapid growth (4–10 weeks) and maturation (10–21 weeks) phases, using single, mechanically skinned fibres from rat extensor digitorum longus (EDL) muscle. Fibres from rats aged 4 and 8 weeks produced lower maximum T-system depolarization-induced force responses and fewer T-system depolarization-induced force responses to 75% run-down than those produced by fibres from rats aged 10 weeks and older. The sensitivity of the contractile apparatus to Ca2+ in fibres from 4-week rats was significantly higher than that in fibres from 10-week rats; however, the maximum Ca2+-activated force per skinned fibre cross-sectional area (specific force) developed by fibres from 4-week rats was on average ∼44% lower than the values obtained for all the other age groups. In agreement with the age difference in specific force, the MHC content of EDL muscles from 4-week rats was ∼29% lower than that of 10-week rats. Thus, mechanically skinned fibres from rats undergoing rapid growth are less responsive to T-system depolarization and maximal Ca2+ activation than fibres from rats at the later stage of maturation or adult rats. These results suggest that during the rapid growth phase in rats, the structure and function of elements involved in E–C coupling in fast-twitch skeletal muscle continue to undergo significant changes.

Journal

Pflügers Archiv European Journal of Physiologyl of PhysiologySpringer Journals

Published: Mar 6, 2008

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off