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Responses of smooth muscle to quick load change studied at high time resolution

Johansson, B; Hellstrand, Per LU and Uvelius, Bengt LU (1978) In Blood Vessels 15(1-3). p.65-82
Abstract
Quick-release and quick-stretch experiments have been performed on preparations of smooth muscle from rat portal vein and rabbit urinary bladder. The low equivalent mass of the isotonic lever (8 mg) implied that inertial oscillations were limited to the first 5-10 msec after the load step. The high time resolution achieved in this way enabled us to separate three components in the length response to a step change in force: (1) an immediate passive elastic recoil, (2) an isotonic velocity transient lasting 50-75 msec and (3) shortening of the contractile element after its full adjustment to the new load. The maximal series elastic recoil was about 10% of the total muscle length in portal vein but only some 3% in urinary bladder. Stiffness... (More)
Quick-release and quick-stretch experiments have been performed on preparations of smooth muscle from rat portal vein and rabbit urinary bladder. The low equivalent mass of the isotonic lever (8 mg) implied that inertial oscillations were limited to the first 5-10 msec after the load step. The high time resolution achieved in this way enabled us to separate three components in the length response to a step change in force: (1) an immediate passive elastic recoil, (2) an isotonic velocity transient lasting 50-75 msec and (3) shortening of the contractile element after its full adjustment to the new load. The maximal series elastic recoil was about 10% of the total muscle length in portal vein but only some 3% in urinary bladder. Stiffness of series elasticity increased in proportion to force and was about 3 times higher in bladder than in portal vein at any force level. Force-velocity relations for loads less than Po could be fitted to Hill's equation; Vmax in 4 AC-stimulated portal veins was 0.53 +/- 0.03 muscle lengths/sec and in 8 K+-activated bladder preparations 0.18 +/- 0.01 muscle lengths/sec. Application of loads greater than Po produced rates of lengthening greater than expected from an extrapolation of Hill's hyperbola. The nature of the transient component is discussed in the light of recent studies of force and velocity transients in skeletal muscle. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Blood Vessels
volume
15
issue
1-3
pages
65 - 82
publisher
Karger
external identifiers
  • pmid:630137
ISSN
0303-6847
language
English
LU publication?
yes
id
f798ab6a-6545-467c-92d6-5af6de23644a (old id 1102699)
date added to LUP
2008-08-14 11:04:41
date last changed
2017-02-22 11:44:31
@article{f798ab6a-6545-467c-92d6-5af6de23644a,
  abstract     = {Quick-release and quick-stretch experiments have been performed on preparations of smooth muscle from rat portal vein and rabbit urinary bladder. The low equivalent mass of the isotonic lever (8 mg) implied that inertial oscillations were limited to the first 5-10 msec after the load step. The high time resolution achieved in this way enabled us to separate three components in the length response to a step change in force: (1) an immediate passive elastic recoil, (2) an isotonic velocity transient lasting 50-75 msec and (3) shortening of the contractile element after its full adjustment to the new load. The maximal series elastic recoil was about 10% of the total muscle length in portal vein but only some 3% in urinary bladder. Stiffness of series elasticity increased in proportion to force and was about 3 times higher in bladder than in portal vein at any force level. Force-velocity relations for loads less than Po could be fitted to Hill's equation; Vmax in 4 AC-stimulated portal veins was 0.53 +/- 0.03 muscle lengths/sec and in 8 K+-activated bladder preparations 0.18 +/- 0.01 muscle lengths/sec. Application of loads greater than Po produced rates of lengthening greater than expected from an extrapolation of Hill's hyperbola. The nature of the transient component is discussed in the light of recent studies of force and velocity transients in skeletal muscle.},
  author       = {Johansson, B and Hellstrand, Per and Uvelius, Bengt},
  issn         = {0303-6847},
  language     = {eng},
  number       = {1-3},
  pages        = {65--82},
  publisher    = {Karger},
  series       = {Blood Vessels},
  title        = {Responses of smooth muscle to quick load change studied at high time resolution},
  volume       = {15},
  year         = {1978},
}