Journal article
Crossbridge kinetics in chemically skinned rabbit psoas fibres when the actin-myosin lattice spacing is altered by dextran T-500
Journal of muscle research and cell motility, Vol.6(3), pp.313-332
1985
DOI: 10.1007/BF00713172
PMID: 2415551
Abstract
The actin-myosin lattice spacing of chemically skinned rabbit psoas fibres was osmotically altered by dextran T500, and the transient kinetic response of tension arising from maximally cycling cross-bridges was measured by sinusoidal length perturbations. The lattice spacing was estimated from the width of the fibres measured under a light microscope. As the dextran concentration was increased, the widths during both relaxation and Ca-activation decreased monotonically. The tension increased to a maximum at 7% dextran, and decreased again at further increases in dextran. Dynamic modulus (stiffness) increased monotonically with compression by dextran; this increase is primarily due to the elastic modulus. The rate constants slightly decreased between 0% and 4% dextran, then decreased rapidly at higher concentrations. The rate of oscillatory work output stayed approximately constant between 0% and 4% dextran, and sharply decreased at higher concentrations. Apparently, two independent effects occur as the lattice is compressed by dextran: (1) a compensation for the spacing change through an increase in tension and a decrease in the rate constants (this takes place at low dextran concentrations); and (2) an alteration of the crossbridge kinetics by grossly decreasing both the tension and the rate constants (at high dextran concentrations). The first effect is interpreted as a decrease in the detachment rate, while the second effect is interpreted as a decrease in the rate of the 'power stroke' reaction.
Details
- Title: Subtitle
- Crossbridge kinetics in chemically skinned rabbit psoas fibres when the actin-myosin lattice spacing is altered by dextran T-500
- Creators
- M KAWAI - Columbia univ., dep. anatomy cell biologyM. I SCHULMAN - Columbia univ., dep. anatomy cell biology
- Resource Type
- Journal article
- Publication Details
- Journal of muscle research and cell motility, Vol.6(3), pp.313-332
- Publisher
- Kluwer Academic Publishers; London; Boston; Dordrecht
- DOI
- 10.1007/BF00713172
- PMID
- 2415551
- ISSN
- 0142-4319
- eISSN
- 1573-2657
- Language
- English
- Date published
- 1985
- Academic Unit
- Anatomy and Cell Biology; Internal Medicine
- Record Identifier
- 9984025682702771
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