Cross-bridge kinetics during shortening in early and sustained contraction of intestinal smooth muscle
(1993) In American Journal of Physiology: Cell Physiology 265(3 Pt 1). p.695-703- Abstract
- Mechanisms responsible for the decrease in shortening velocity after prolonged contraction ("latch" state) were investigated at identical force during early (20 s, "phasic") and sustained (5 min, "tonic") phases of high-K+ (25-30 mM) contractions in smooth muscle of guinea pig taenia coli. Cytoplasmic Ca2+ concentration, myosin light-chain phosphorylation, and maximum shortening velocity all declined from 20 s to 5 min of contraction. The time course of shortening following isotonic quick release was biexponential, with a fastest rate constant of approximately 80 s-1 in both phasic and tonic contractions. Stiffness was identical in phasic and tonic contraction; however, after a release to slack length and unloaded shortening, stiffness... (More)
- Mechanisms responsible for the decrease in shortening velocity after prolonged contraction ("latch" state) were investigated at identical force during early (20 s, "phasic") and sustained (5 min, "tonic") phases of high-K+ (25-30 mM) contractions in smooth muscle of guinea pig taenia coli. Cytoplasmic Ca2+ concentration, myosin light-chain phosphorylation, and maximum shortening velocity all declined from 20 s to 5 min of contraction. The time course of shortening following isotonic quick release was biexponential, with a fastest rate constant of approximately 80 s-1 in both phasic and tonic contractions. Stiffness was identical in phasic and tonic contraction; however, after a release to slack length and unloaded shortening, stiffness during restretch was greater in tonic contraction (51 vs. 43% of isometric stiffness after 16 ms of unloaded shortening). Stiffness decreased after release with a rate constant of approximately 200 s-1, slightly greater in phasic than in tonic contraction. The results indicate that the number of attached cross bridges during unloaded shortening, while substantially reduced relative to the isometric value, is higher in latch than in nonlatch, consistent with a lower detachment relative to attachment rate. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1107369
- author
- Hellstrand, Per LU and Nordström, Ina LU
- organization
- publishing date
- 1993
- type
- Contribution to journal
- publication status
- published
- subject
- in
- American Journal of Physiology: Cell Physiology
- volume
- 265
- issue
- 3 Pt 1
- pages
- 695 - 703
- publisher
- American Physiological Society
- external identifiers
-
- pmid:8214026
- scopus:0027666049
- ISSN
- 1522-1563
- language
- English
- LU publication?
- yes
- id
- 962f1721-31b0-42b2-9a36-ff711534e25e (old id 1107369)
- date added to LUP
- 2016-04-01 17:09:27
- date last changed
- 2021-01-03 05:42:00
@article{962f1721-31b0-42b2-9a36-ff711534e25e,
abstract = {{Mechanisms responsible for the decrease in shortening velocity after prolonged contraction ("latch" state) were investigated at identical force during early (20 s, "phasic") and sustained (5 min, "tonic") phases of high-K+ (25-30 mM) contractions in smooth muscle of guinea pig taenia coli. Cytoplasmic Ca2+ concentration, myosin light-chain phosphorylation, and maximum shortening velocity all declined from 20 s to 5 min of contraction. The time course of shortening following isotonic quick release was biexponential, with a fastest rate constant of approximately 80 s-1 in both phasic and tonic contractions. Stiffness was identical in phasic and tonic contraction; however, after a release to slack length and unloaded shortening, stiffness during restretch was greater in tonic contraction (51 vs. 43% of isometric stiffness after 16 ms of unloaded shortening). Stiffness decreased after release with a rate constant of approximately 200 s-1, slightly greater in phasic than in tonic contraction. The results indicate that the number of attached cross bridges during unloaded shortening, while substantially reduced relative to the isometric value, is higher in latch than in nonlatch, consistent with a lower detachment relative to attachment rate.}},
author = {{Hellstrand, Per and Nordström, Ina}},
issn = {{1522-1563}},
language = {{eng}},
number = {{3 Pt 1}},
pages = {{695--703}},
publisher = {{American Physiological Society}},
series = {{American Journal of Physiology: Cell Physiology}},
title = {{Cross-bridge kinetics during shortening in early and sustained contraction of intestinal smooth muscle}},
volume = {{265}},
year = {{1993}},
}