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Cross-bridge kinetics and shortening in smooth muscle

Hellstrand, Per LU (1994) In Canadian Journal of Physiology and Pharmacology 72(11). p.1334-1337
Abstract
Stiffness measurements were performed on smooth muscle preparations from guinea-pig taenia coli to obtain information on the number of attached cross bridges under varying contractile conditions. The normalized stiffness of the cross-bridge system in smooth muscle may be of a magnitude similar to that assumed in skeletal muscle. Transition from isometric contraction to unloaded shortening was associated with a decrease in stiffness to 50% or less of the isometric value, slightly higher than that found in skeletal muscle fibers. Comparison of phasic (5 s) and tonic (5 min) contractions showed lower Vmax, intracellular [Ca2+], and myosin 20 kDa light chain phosphorylation at 5 min, indicating development of a latch state. Isometric force and... (More)
Stiffness measurements were performed on smooth muscle preparations from guinea-pig taenia coli to obtain information on the number of attached cross bridges under varying contractile conditions. The normalized stiffness of the cross-bridge system in smooth muscle may be of a magnitude similar to that assumed in skeletal muscle. Transition from isometric contraction to unloaded shortening was associated with a decrease in stiffness to 50% or less of the isometric value, slightly higher than that found in skeletal muscle fibers. Comparison of phasic (5 s) and tonic (5 min) contractions showed lower Vmax, intracellular [Ca2+], and myosin 20 kDa light chain phosphorylation at 5 min, indicating development of a latch state. Isometric force and stiffness were identical in the two types of contraction. However, stiffness during unloaded shortening was greater in the latch state, which may be the result of the presence of a population of cross bridges with a low rate constant for detachment. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Canadian Journal of Physiology and Pharmacology
volume
72
issue
11
pages
1334 - 1337
publisher
National Research Council Canada
external identifiers
  • pmid:7767875
  • scopus:0028633626
ISSN
0008-4212
language
English
LU publication?
yes
id
efc4e3ac-f155-4dd0-921d-556b0611077c (old id 1108286)
date added to LUP
2008-07-23 16:51:34
date last changed
2017-01-01 04:59:15
@article{efc4e3ac-f155-4dd0-921d-556b0611077c,
  abstract     = {Stiffness measurements were performed on smooth muscle preparations from guinea-pig taenia coli to obtain information on the number of attached cross bridges under varying contractile conditions. The normalized stiffness of the cross-bridge system in smooth muscle may be of a magnitude similar to that assumed in skeletal muscle. Transition from isometric contraction to unloaded shortening was associated with a decrease in stiffness to 50% or less of the isometric value, slightly higher than that found in skeletal muscle fibers. Comparison of phasic (5 s) and tonic (5 min) contractions showed lower Vmax, intracellular [Ca2+], and myosin 20 kDa light chain phosphorylation at 5 min, indicating development of a latch state. Isometric force and stiffness were identical in the two types of contraction. However, stiffness during unloaded shortening was greater in the latch state, which may be the result of the presence of a population of cross bridges with a low rate constant for detachment.},
  author       = {Hellstrand, Per},
  issn         = {0008-4212},
  language     = {eng},
  number       = {11},
  pages        = {1334--1337},
  publisher    = {National Research Council Canada},
  series       = {Canadian Journal of Physiology and Pharmacology},
  title        = {Cross-bridge kinetics and shortening in smooth muscle},
  volume       = {72},
  year         = {1994},
}