Cardiac quick-release contraction mechanoenergetics analysis using a cardiac muscle cross-bridge model

1995 ◽  
Vol 268 (6) ◽  
pp. H2544-H2552
Author(s):  
T. W. Taylor ◽  
Y. Goto ◽  
K. Hata ◽  
T. Takasago ◽  
A. Saeki ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Muscle Fiber ◽  
Rate Constants ◽  
Fiber Length ◽  
Atp Hydrolysis ◽  
Energy Utilization ◽  
Quick Release ◽  
Cross Bridge ◽  
Bridge Model ◽  
The Cross

Huxley's sliding filament cross-bridge muscle model coupled with parallel and series elastic components was simulated to examine the conflicting reports on the amount of energy saved by quick release at the peak contraction time. Cross-bridge energy utilization was determined by considering the ATP hydrolysis for the cross-bridge cycling. The quick-release cases were simulated by letting the muscle fiber suddenly shorten to the resting fiber length at peak systole, and then the contraction was allowed to continue at the resting length. Simulation results demonstrated that, using realistic parameter values, typically approximately 15% of the muscle fiber energy is used after peak systole (and approximately 30% of the cross-bridge energy), but this is also a function of the muscle fiber properties characterized by cross-bridge association and dissociation rate constants. Increasing the kinetic rate constants, the series elasticity, the initial fiber length, or the time of peak intracellular calcium will increase the amount of energy left, which may explain some of the discrepancies in the literature. Cardiac muscle hypertrophy will increase the fraction of muscle fiber energy left after peak systole to approximately 30%. The strongest indicator of the percent energy left at peak systole was the time the fiber reached peak systole, and as the fiber reached peak systole faster, the amount of energy saved by quick release increased.

Variable cross-bridge cycling-ATP coupling accounts for cardiac mechanoenergetics

1993 ◽  
Vol 264 (3) ◽  
pp. H994-H1004 ◽  
Author(s):  
T. W. Taylor ◽  
Y. Goto ◽  
H. Suga
Keyword(s):  
Muscle Fiber ◽  
Atp Hydrolysis ◽  
Mechanical Energy ◽  
Variable Cross ◽  
Cross Bridge ◽  
Lower Activation ◽  
Total Mechanical Energy ◽  
The Cross ◽  
Experimental Findings ◽  
Isotonic Contractions

Cardiac twitch contractions were simulated by Huxley's sliding filament cross-bridge muscle model coupled with parallel and series elastic components. The energetics of the contraction were based on the ATP hydrolysis for the cross-bridge cycling. Force-length area (FLA), as a measure of the total mechanical energy, was computed for both isometric and isotonic contractions in a manner similar to the pressure-volume area (PVA) (Suga, H. Physiol. Rev. 70: 247–277, 1990). PVA correlates linearly with cardiac oxygen consumption, and since FLA is analogous to PVA, FLA should correlate with the ATP expended. Simulations comparing FLA with the cross-bridge cycling ATP usage showed that at lower muscle fiber activation levels (shorter initial fiber lengths and lower preload levels) FLA decreased more rapidly than the number of muscle fiber cross-bridge cycles in both isometric and isotonic contraction cases. This suggests that one ATP can cause more than one cross-bridge cycle at lower activation levels as was proposed by Yanagida, Arata, and Oosawa (Nature 316: 366–369, 1985). If the number of cross-bridge cycles to ATP ratio is allowed to increase at lower activation levels as suggested by Yanagida et al., Huxley's model is compatible with the experimental findings on FLA and PVA.

The Frank-Starling mechanism is not mediated by changes in rate of cross-bridge detachment

1997 ◽  
Vol 273 (5) ◽  
pp. H2428-H2435 ◽  
Author(s):  
Thomas Wannenburg ◽  
Paul M. L. Janssen ◽  
Dongsheng Fan ◽  
Pieter P. De Tombe
Keyword(s):  
Cardiac Muscle ◽  
Maximum Rate ◽  
Sarcomere Length ◽  
Myosin Head ◽  
Isometric Force ◽  
Force Development ◽  
Cross Bridge ◽  
Average Slope ◽  
The Cross ◽  
Kinetics Of

We tested the hypothesis that the Frank-Starling relationship is mediated by changes in the rate of cross-bridge detachment in cardiac muscle. We simultaneously measured isometric force development and the rate of ATP consumption at various levels of Ca2+ activation in skinned rat cardiac trabecular muscles at three sarcomere lengths (2.0, 2.1, and 2.2 μm). The maximum rate of ATP consumption was 1.5 nmol ⋅ s−1 ⋅ μl fiber vol−1, which represents an estimated adenosinetriphosphatase (ATPase) rate of ∼10 s−1 per myosin head at 24°C. The rate of ATP consumption was tightly and linearly coupled to the level of isometric force development, and changes in sarcomere length had no effect on the slope of the force-ATPase relationships. The average slope of the force-ATPase relationships was 15.5 pmol ⋅ mN−1 ⋅ mm−1. These results suggest that the mechanisms that underlie the Frank-Starling relationship in cardiac muscle do not involve changes in the kinetics of the apparent detachment step in the cross-bridge cycle.

scholarly journals Is the Cross-Bridge Stiffness Proportional to Tension during Muscle Fiber Activation?

2010 ◽  
Vol 98 (11) ◽  
pp. 2582-2590 ◽  
Author(s):  
Barbara Colombini ◽  
Marta Nocella ◽  
M. Angela Bagni ◽  
Peter J. Griffiths ◽  
Giovanni Cecchi
Keyword(s):  
Muscle Fiber ◽  
Cross Bridge ◽  
The Cross

scholarly journals Invited Review: Plasticity and energetic demands of contraction in skeletal and cardiac muscle

2001 ◽  
Vol 90 (3) ◽  
pp. 1158-1164 ◽  
Author(s):  
Gary C. Sieck ◽  
Michael Regnier
Keyword(s):  
Conceptual Framework ◽  
Cardiac Muscle ◽  
Myosin Heavy Chain ◽  
Muscle Fiber ◽  
Heavy Chain ◽  
Atp Hydrolysis ◽  
Actin Binding ◽  
Energetic Properties ◽  
Cardiac Muscle Fibers ◽  
Muscle Remodeling

Numerous studies have explored the energetic properties of skeletal and cardiac muscle fibers. In this mini-review, we specifically explore the interactions between actin and myosin during cross-bridge cycling and provide a conceptual framework for the chemomechanical transduction that drives muscle fiber energetic demands. Because the myosin heavy chain (MHC) is the site of ATP hydrolysis and actin binding, we focus on the mechanical and energetic properties of different MHC isoforms. Based on the conceptual framework that is provided, we discuss possible sites where muscle remodeling may impact the energetic demands of contraction in skeletal and cardiac muscle.

scholarly journals Dynamics of cross-bridge cycling, ATP hydrolysis, force generation, and deformation in cardiac muscle

2016 ◽  
Vol 96 ◽  
pp. 11-25 ◽  
Author(s):  
Shivendra G. Tewari ◽  
Scott M. Bugenhagen ◽  
Bradley M. Palmer ◽  
Daniel A. Beard
Keyword(s):  
Cardiac Muscle ◽  
Atp Hydrolysis ◽  
Force Generation ◽  
Cross Bridge

scholarly journals ADP binding to myosin cross-bridges and its effect on the cross-bridge detachment rate constants.

1987 ◽  
Vol 89 (6) ◽  
pp. 905-920 ◽  
Author(s):  
M Schoenberg ◽  
E Eisenberg
Keyword(s):  
Dissociation Constant ◽  
Active Site ◽  
Rate Constants ◽  
Competitive Inhibition ◽  
Psoas Muscle ◽  
Nucleotide Analogues ◽  
Cross Bridge ◽  
Detachment Rate ◽  
The Cross ◽  
Cross Bridges

We have studied the binding of adenosine diphosphate (ADP) to attached cross-bridges in chemically skinned rabbit psoas muscle fibers and the effect of that binding on the cross-bridge detachment rate constants. Cross-bridges with ADP bound to the active site behave very similarly to cross-bridges without any nucleotide at the active site. First, fiber stiffness is the same as in rigor, which presumably implies that, as in rigor, all the cross-bridges are attached. Second, the cross-bridge detachment rate constants in the presence of ADP, measured from the rate of decay of the force induced by a small stretch, are, over a time scale of minutes, similar to those seen in rigor. Because ADP binding to the active site does not cause an increase in the cross-bridge detachment rate constants, whereas binding of nucleotide analogues such as adenyl-5'-yl imidodiphosphate (AMP-PNP) and pyrophosphate (PPi) do, it was possible, by using ADP as a competitive inhibitor of PPi or AMP-PNP, to measure the competitive inhibition constant and thereby the dissociation constant for ADP binding to attached cross-bridges. We found that adding 175 microM ADP to 4 mM PPi or 4 mM AMP-PNP produces as much of a decrease in the apparent cross-bridge detachment rate constants as reducing the analogue concentration from 4 to 1 mM. This suggests that ADP is binding to attached cross-bridges with a dissociation constant of approximately 60 microM. This value is quite similar to that reported for ADP binding to actomyosin subfragment-1 (acto-S1) in solution, which provides further support for the idea that nucleotides and nucleotide analogues seem to bind about as strongly to attached cross-bridges in fibers as to acto-S1 in solution (Johnson, R.E., and P. H. Adams. 1984. FEBS Letters. 174:11-14; Schoenberg, M., and E. Eisenberg. 1985. Biophysical Journal. 48:863-871; Biosca, J.A., L.E. Greene, and E. Eisenberg. 1986. Journal of Biological Chemistry. 261:9793-9800).

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