Force recovery after activated shortening in whole skeletal muscle: transient and steady-state aspects of force depression

2005 ◽  
Vol 99 (1) ◽  
pp. 252-260 ◽  
Author(s):  
David T. Corr ◽  
Walter Herzog
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Isometric Force ◽  
Mechanical Work ◽  
Transient Phenomena ◽  
Cross Bridge ◽  
Force Depression ◽  
In Situ Experiments ◽  
Force Recovery ◽  
Cross Bridges

The depression of isometric force after active shortening is a well-accepted characteristic of skeletal muscle, yet its mechanisms remain unknown. Although traditionally analyzed at steady state, transient phenomena caused, at least in part, by cross-bridge kinetics may provide novel insight into the mechanisms associated with force depression (FD). To identify the transient aspects of FD and its relation to shortening speed, shortening amplitude, and muscle mechanical work, in situ experiments were conducted in soleus muscle-tendon units of anesthetized cats. The period immediately after shortening, in which force recovers toward steady state, was fit by using an exponential recovery function ( R2 > 0.99). Statistical analyses revealed that steady-state FD (FDss) increased with shortening amplitude and mechanical work. This FDss increase was always accompanied by a significant decrease in force recovery rate. Furthermore, a significant reduction in stiffness was observed after all activated shortenings, presumably because of a reduced proportion of attached cross bridges. These results were interpreted with respect to the two most prominent proposed mechanisms of force depression: sarcomere length nonuniformity theory ( 7 , 32 ) and a stress-induced inhibition of cross-bridge binding in the newly formed actin-myosin overlap zone ( 14 , 28 ). We hypothesized that the latter could describe both steady-state and transient aspects of FD using a single scalar variable, the mechanical work done during shortening. As either excursion (overlap) or force (stress) is increased, mechanical work increases, and cross-bridge attachment would become more inhibited, as supported by this study in which an increase in mechanical work resulted in a slower recovery to a more depressed steady-state force.

Force Recovery After Activated Stretching in Whole Skeletal Muscle: Transient Aspects of Force Enhancement

2008 ◽  
Author(s):  
Ryan A. Koppes ◽  
David T. Corr
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Isometric Force ◽  
Underlying Mechanism ◽  
Mechanical Work ◽  
Force Enhancement ◽  
Transient Phenomena ◽  
Force Depression ◽  
Force Relaxation ◽  
In Situ Experiments

The enhancement of isometric force after active stretching is a well-accepted and demonstrated characteristic of skeletal muscle in both whole muscle [1,2] and single-fiber preparations [1,3], but its mechanisms remain unknown. Although traditionally analyzed at steady-state, transient phenomena caused, at least in part, by cross-bridge kinetics may provide novel insight into the mechanisms associated with force enhancement (FE). In order to identify the transient aspects of FE and its relation to stretching speed, stretching amplitude, and muscle mechanical work, a post hoc analysis of in situ experiments in soleus muscle tendon units of anesthetized cats [2] was conducted. The period immediately following stretching, at which the force returns to steady-state, was fit using an exponential decay function. The aims of this study were to analyze and quantify the effects of stretching amplitude, stretching speed, and muscle mechanical work on steady-state force enhancement (FEss) and transient force relaxation rate after active stretching. The results of this study were interpreted with respect to prior force depression (FD) experiments [4], to identify if the two phenomena exhibited similar transient and steady-state behaviors, and thus could be described by the same underlying mechanism(s).

scholarly journals A new experimental model to study force depression: the Drosophila jump muscle

2014 ◽  
Vol 116 (12) ◽  
pp. 1543-1550 ◽  
Author(s):  
Ryan A. Koppes ◽  
Douglas M. Swank ◽  
David T. Corr
Keyword(s):  
Steady State ◽  
Experimental Model ◽  
Fiber Length ◽  
Isometric Force ◽  
Underlying Mechanism ◽  
Mammalian Skeletal Muscle ◽  
Force Depression ◽  
Force Recovery ◽  
Sarcomere Proteins ◽  
Initial Force

Force depression (FD) is a decrease in isometric force following active muscle shortening. Despite being well characterized experimentally, its underlying mechanism remains unknown. To develop a new, genetically manipulatable experimental model that would greatly improve our ability to study the underlying mechanism(s) of FD, we tested the Drosophila jump muscle for classical FD behavior. Steady-state force generation following active shortening decreased by 2, 8, and 11% of maximum isometric force with increasing shortening amplitudes of 5, 10, and 20% of optimal fiber length, and decreased by 11, 8, and 5% with increasing shortening velocities of 4, 20, and 200% of optimal fiber length per second. These steady-state FD (FDSS) characteristics of Drosophila jump muscle mimic those observed in mammalian skeletal muscle. A double exponential fit of transient force recovery following shortening identified two separate phases of force recovery: a rapid initial force redevelopment, and a slower recovery toward steady state. This analysis showed the slower rate of force redevelopment to be inversely proportional to the amount of FDSS, while the faster rate did not correlate with FDSS. This suggests that the mechanism behind the slower, most likely cross-bridge cycling rate, influences the amount of FDSS. Thus the jump muscle, when coupled with the genetic mutability of its sarcomere proteins, offers a unique and powerful experimental model to explore the underlying mechanism behind FD.

Transient and Steady-State Force Enhancement in the Drosophila Jump Muscle

2012 ◽  
Author(s):  
Ryan A. Koppes ◽  
Douglas M. Swank ◽  
David T. Corr
Keyword(s):  
Steady State ◽  
Isometric Force ◽  
Recovery Period ◽  
Underlying Mechanism ◽  
Clear Correlation ◽  
Force Enhancement ◽  
Force Depression ◽  
Force Recovery ◽  
State Force ◽  
Whole Muscle

The increase of isometric force after active lengthening, termed force enhancement (FE), is a well-accepted characteristic of skeletal muscle that has been demonstrated in both whole muscle [1,3] and single-fiber preparations [1,2]. The amount of FE increases with increasing amplitudes of stretch, yet no clear correlation between FE and the rate stretch has been demonstrated [2]. Although this behavior has been observed experimentally for over 70 years, its underlying mechanism(s) remain unknown. Furthermore, most studies of FE have been limited to steady-state (FESS) observations [1–3], whereas clues to the underlying mechanism(s) may very well exist in the transient force recovery period following an active stretch, as seen in another history-dependent phenomenon, force depression [4].

Smooth muscle energetics and theories of cross-bridge regulation

1990 ◽  
Vol 258 (2) ◽  
pp. C369-C375 ◽  
Author(s):  
R. J. Paul
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Steady State ◽  
Time Course ◽  
Isometric Force ◽  
Muscle Energetics ◽  
Cross Bridge ◽  
Tension Cost ◽  
Low Tension ◽  
Smooth Muscle Energetics

The energetics of smooth muscle is characterized by low tension cost (rate of ATP utilization per isometric force/cross-section area), ranging from 100- to 500-fold less than skeletal muscle. The efficiency (ATP usage per work) of smooth muscle, although less well documented, is also somewhat (4-fold) less than skeletal muscle. Another well-known characteristic of smooth muscle is the linear relation between the steady-state of ATP utilization (JATP) and isometric force. Recently, Murphy and colleagues [C.-M. Hai and R. A. Murphy. Am. J. Physiol. 254 (Cell Physiol. 23) C99-C106, 1988] have put forth a kinetic model of cross-bridge regulation that predicts the time course of stress and myosin light chain phosphorylation (MLC-Pi). The energetics consequences of this model, in brief, are that the low tension cost is partly attributed to a slow detachment rate of the myosin cross bridge when dephosphorylated when attached to actin ("latch state"), whereas the lower efficiency is ascribed to a high rate of myosin phosphorylation-dephosphorylation inherent to a fit of data to this kinetic scheme. This latter corollary is somewhat controversial in light of current interpretations of smooth muscle energetics data. Using SCoP software (National Biomedical Simulation Resource, Duke University), we tested this model in terms of fitting existing data with respect to 1) is a high myosin-dephosphorylation adenosine triphosphatase (ATPase) necessary to fit the available data on the time course of stress and MLC-Pi?; and 2) can this model predict the observed linear relation between the steady-state rate of ATP hydrolysis (JATP) and isometric force?(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-bridge kinetics and shortening in smooth muscle

1994 ◽  
Vol 72 (11) ◽  
pp. 1334-1337 ◽  
Author(s):  
Per Hellstrand
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Isometric Force ◽  
Muscle Mechanics ◽  
Cross Bridge ◽  
Intracellular Ca ◽  
Cross Bridges ◽  
Latch State ◽  
Smooth Muscle Mechanics ◽  
Low Rate

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.Key words: smooth muscle mechanics, cross bridges, latch, myosin phosphorylation.

scholarly journals Variation in isometric force after active shortening and lengthening and their mechanisms: a review

2014 ◽  
Vol 27 (1) ◽  
pp. 141-153
Author(s):  
Rodrigo Troyack de Lima ◽  
Paulo Farinatti ◽  
Walace Monteiro ◽  
Carlos Gomes de Oliveira
Keyword(s):  
Skeletal Muscle ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Isometric Force ◽  
Force Enhancement ◽  
Literature Searching ◽  
History Dependence ◽  
Force Depression ◽  
Key Variables ◽  
Cross Bridges

Introduction The isometric force history dependence of skeletal muscle has been studied along the last one hundred years. Several theories have been formulated to explain and establish the causes of the phenomenon, but not successfully, as they have not been fully accepted and demonstrated, and much controversy on such a subject still remains. Objective To present a systematic literature review on the dynamics of the mechanisms of force depression and force enhancement after active shortening and lengthening, respectively, identifying the key variables involved in the phenomenon, and to date to present the main theories and hypothesis developed trying to explaining it. Method The procedure of literature searching complied the major databases, including articles either, those which directly investigated the phenomena of force depression and force enhancement or those which presented possible causes and mechanisms associated with their respective events, from the earliest studies published until the year of 2010. Results 97 references were found according to the criteria used. Conclusion Based on this review, it is suggested that the theory of stress inhibition of actin-myosin cross-bridges is that better explain the phenomenon of force depression. Whereas regarding the force enhancement phenomenon, one theory have been well accepted, the increased number of actin-myosin cross-bridges in strong binding state influenced by the recruitment of passive elastic components, which hole is attributed to the titin filament.

scholarly journals Comparison of putative cooperative mechanisms in cardiac muscle: length dependence and dynamic responses

1999 ◽  
Vol 276 (5) ◽  
pp. H1734-H1754 ◽  
Author(s):  
J. Jeremy Rice ◽  
Raimond L. Winslow ◽  
William C. Hunter
Keyword(s):  
Steady State ◽  
Thin Filament ◽  
Sarcomere Length ◽  
Isometric Force ◽  
Muscle Length ◽  
Dynamic Responses ◽  
Force Generation ◽  
Cross Bridge ◽  
Multiple Cross ◽  
Cross Bridges

Length-dependent steady-state and dynamic responses of five models of isometric force generation in cardiac myofilaments were compared with similar experimental data from the literature. The models were constructed by assuming different subsets of three putative cooperative mechanisms. Cooperative mechanism 1 holds that cross-bridge binding increases the affinity of troponin for Ca2+. In the models, cooperative mechanism 1can produce steep force-Ca2+(F-Ca) relations, but apparent cooperativity is highest at midlevel Ca2+ concentrations. During twitches, cooperative mechanism 1 has the effect of increasing latency to peak as the magnitude of force increases, an effect not seen experimentally. Cooperative mechanism 2 holds that the binding of a cross bridge increases the rate of formation of neighboring cross bridges and that multiple cross bridges can maintain activation of the thin filament in the absence of Ca2+. Only cooperative mechanism 2 can produce sarcomere length (SL)-dependent prolongation of twitches, but this mechanism has little effect on steady-state F-Ca relations. Cooperativity mechanism 3 is designed to simulate end-to-end interactions between adjacent troponin and tropomyosin. This mechanism can produce steep F-Ca relations with appropriate SL-dependent changes in Ca2+ sensitivity. With the assumption that tropomyosin shifting is faster than cross-bridge cycling, cooperative mechanism 3produces twitches where latency to peak is independent of the magnitude of force, as seen experimentally.

scholarly journals Characterization of cross-bridge elasticity and kinetics of cross-bridge cycling during force development in single smooth muscle cells.

1988 ◽  
Vol 91 (6) ◽  
pp. 761-779 ◽  
Author(s):  
D M Warshaw ◽  
D D Rees ◽  
F S Fay
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Isometric Force ◽  
Force Development ◽  
Cross Bridge ◽  
Tension Recovery ◽  
Length Changes ◽  
Cross Bridges ◽  
Initial Force ◽  
Kinetics Of

Force development in smooth muscle, as in skeletal muscle, is believed to reflect recruitment of force-generating myosin cross-bridges. However, little is known about the events underlying cross-bridge recruitment as the muscle cell approaches peak isometric force and then enters a period of tension maintenance. In the present studies on single smooth muscle cells isolated from the toad (Bufo marinus) stomach muscularis, active muscle stiffness, calculated from the force response to small sinusoidal length changes (0.5% cell length, 250 Hz), was utilized to estimate the relative number of attached cross-bridges. By comparing stiffness during initial force development to stiffness during force redevelopment immediately after a quick release imposed at peak force, we propose that the instantaneous active stiffness of the cell reflects both a linearly elastic cross-bridge element having 1.5 times the compliance of the cross-bridge in frog skeletal muscle and a series elastic component having an exponential length-force relationship. At the onset of force development, the ratio of stiffness to force was 2.5 times greater than at peak isometric force. These data suggest that, upon activation, cross-bridges attach in at least two states (i.e., low-force-producing and high-force-producing) and redistribute to a steady state distribution at peak isometric force. The possibility that the cross-bridge cycling rate was modulated with time was also investigated by analyzing the time course of tension recovery to small, rapid step length changes (0.5% cell length in 2.5 ms) imposed during initial force development, at peak force, and after 15 s of tension maintenance. The rate of tension recovery slowed continuously throughout force development following activation and slowed further as force was maintained. Our results suggest that the kinetics of force production in smooth muscle may involve a redistribution of cross-bridge populations between two attached states and that the average cycling rate of these cross-bridges becomes slower with time during contraction.

scholarly journals Force generated by myosin cross-bridges is reduced in myofibrils exposed to ROS/RNS

2019 ◽  
Vol 317 (6) ◽  
pp. C1304-C1312 ◽  
Author(s):  
Malin Persson ◽  
Maarten M. Steinz ◽  
Håkan Westerblad ◽  
Johanna T. Lanner ◽  
Dilson E. Rassier
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Posttranslational Modifications ◽  
Isometric Force ◽  
Force Production ◽  
Indirect Evidence ◽  
Cross Bridge ◽  
Atomic Force ◽  
The Cross ◽  
Cross Bridges

Skeletal muscle weakness is associated with oxidative stress and oxidative posttranslational modifications on contractile proteins. There is indirect evidence that reactive oxygen/nitrogen species (ROS/RNS) affect skeletal muscle myofibrillar function, although the details of the acute effects of ROS/RNS on myosin-actin interactions are not known. In this study, we examined the effects of peroxynitrite (ONOO−) on the contractile properties of individual skeletal muscle myofibrils by monitoring myofibril-induced displacements of an atomic force cantilever upon activation and relaxation. The isometric force decreased by ~50% in myofibrils treated with the ONOO− donor (SIN-1) or directly with ONOO−, which was independent of the cross-bridge abundancy condition (i.e., rigor or relaxing condition) during SIN-1 or ONOO− treatment. The force decrease was attributed to an increase in the cross-bridge detachment rate ( gapp) in combination with a conservation of the force redevelopment rate (kTr) and hence, an increase in the population of cross-bridges transitioning from force-generating to non-force-generating cross-bridges during steady-state. Taken together, the results of this study provide important information on how ROS/RNS affect myofibrillar force production which may be of importance for conditions where increased oxidative stress is part of the pathophysiology.

Oxytocin-mediated recruitment of slowly cycling cross bridges and isometric force in rat myometrium

1996 ◽  
Vol 270 (2) ◽  
pp. E203-E208
Author(s):  
A. L. Ruzycky ◽  
B. T. Ameredes
Keyword(s):  
Isometric Force ◽  
Additional Stress ◽  
Shortening Velocity ◽  
Cycling Rate ◽  
Quick Release ◽  
Cross Bridge ◽  
Cross Bridges ◽  
Unit Stress ◽  
Release Method ◽  
The Relationship

The relationship between cross-bridge cycling rate and isometric stress was investigated in rat myometrium. Stress production by myometrial strips was measured under resting, K+ depolarization, and oxytocin-stimulated conditions. Cross-bridge cycling rates were determined from measurements of maximal unloaded shortening velocity, using the quick-release method. Force redevelopment after the quick release was used as an index of cross-bridge attachment. With maximal K+ stimulation, stress increased with increased cross-bridge cycling (+76%; P < 0.05) and attached cross bridges (+112%; P < 0.05). Addition of oxytocin during K+ stimulation further increased stress (+30%; P < 0.05). With this force component, the cross-bridge cycling rate decreased (-60%; P < 0.05) similar to that under resting conditions. Attached cross-bridges did not increase with this additional stress. The results suggest two distinct mechanisms mediating myometrial contractions. One requires elevated intracellular calcium and rapidly cycling cross bridges. The other mechanism may be independent of calcium and appears to be mediated by slowly cycling cross bridges, supporting greater unit stress.

Sign in / Sign up

Export Citation Format

Share Document