The Force-Load-Velocity Relation and the Viscous-Like Force in the Frog Skeletal Muscle

Mashima, Hidenobu; Akazawa, Kenzo; Kushima, Hiroki; Fujii, Katsuhiko

doi:10.2170/jjphysiol.22.103

Cited by 77 publications

(61 citation statements)

References 19 publications

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“…The tension-length relation of the tetanized frog ventricular muscle studied by MASHIMA(1977)was confirmed in the present study.Between 0.5-0.9 Lmax the developed tension increased linearly with increasing muscle length,and the resting tension increased apparently beyond 0.9Lmax.Eventually,in the 2 sec tetanic afterloaded contraction,the contracted length was not a fixed one which is independent of the initial length,although the amount of shortening increased with increasing initial length (Fig.5).On the tension-length diagram (Fig.6A), the contracted length in the afterloaded contraction did not coincide with the isometric tension-length curve(T)and the discrepancy increased with increasing initial length.For example,when the load was 0.5g and the initial length was 6.53mm,the amount of shortening was x and the contracted tension-length point Vol.31,No.2,1981 Fig.5.…”

Section: A) Canine Left Ventriclesupporting

confidence: 86%

Depressive effects of active shortening on stoke volume of left ventricle and shortening amount of isolated ventricular muscle.

Okada

1981

Jpn.J.Physiol

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In the cross-circulated canine heart-lung preparation,the stroke volume(SV)or the end-systolic volume increased linearly with increasing end-diastolic volume(EDV)when the afterloading impedance was fixed.Exactly the same result was obtained in the relation between the initial length(I)and the amount of shortening(S)for the tetanic contraction of isolated frog ventricular muscle.The slope of the EDV-SV or I-S relation was less than 1.0,suggesting that a kind of depressive effect or a deactivation of contraction was working during the active shortening of cardiac muscle.The slope,which inversely reflects the degree of deactivation,slightly tended to 1.0 with decreasing load and markedly by inotropic intervention,but it was not changed by partial ischemia.The horizontal axis intercept of the EDV-SV or I-S relation, which reflects the ability of the cardiac muscle to shorten under a specified afterloaded condition,shifted to the right(the ability decreased)at a larger load or under partial ischemia but shifted to the left with inotropic intervention. The deactivation increased linearly with the amount of active shortening but no deactivation was observed when there was no active shortening or no load.The mechanism of the deactivation is not due to a shortage of active-state duration but probably due to a depressive effect on Ca2+ utilization of the contractile system during the sliding phase of myofilaments.With reference to the skeletal muscle,a discrepancy is reported between the tension-length diagram determined by isometric tetanic contractions and that determined by isotonic or afterloaded contractions (BUCHTHAL and KAISER,1951; DELEZE,1961;EDMAN,1975).A kind of depression of mechanical performance by active shortening will occur during twitch and tetanus of muscle fiber.According to EDMAN(1980),the depressive effects are consistent with a true deactivation of the contractile system.The depressive effect of myocardial mechanical performance by active shortening has also been reported.For example,

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Section: A) Canine Left Ventriclesupporting

confidence: 86%

Depressive effects of active shortening on stoke volume of left ventricle and shortening amount of isolated ventricular muscle.

Okada

1981

Jpn.J.Physiol

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“…On the other hand, MEIss and SONNENBLICK (1972) determined the force-velocity relation in the cat papillary muscle by the isovelocity method in which the corresponding force was measured during the isovelocity contraction, and confirmed that the force-velocity curve thus obtained coincided with the force-velocity curve determined by the isotonic method. This was also confirmed in the frog skeletal muscle (MASHIMA et a!.,1972) and in the frog ventricular muscle (OKUYAMA et al, 1982).…”

Section: Discussionmentioning

confidence: 67%

Pressure-velocity relation in the isolated rabbit left ventricle.

Okuyama

1983

Jpn.J.Physiol

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The relation between pressure (P) and ejection velocity (J') was determined in the coronary-perfused rabbit left ventricle. The heart was isolated and a thin latex balloon was inserted into the left ventricle. The volume of the ventricle was changed at a constant velocity with a magnetic shaker connected to the balloon at various phases of contraction and the corresponding pressure change was measured. The pressure-velocity relation determined by this isovelocity method was well fitted by a hyperbolic equation, (PEA) (V+B)=B(P0±A), where A and B are constants and P o is the maximum systolic pressure. Using the thick-walled spherical ventricle model, the Hill equation of the ventricular wall muscle with constants a and b was obtained, and Hill constants (a and b) were calculated from ventricular constants (A and B). The constants A and B/V (V is the volume of ventricle) increased with decreases in ventricular volume, but the ratio Vmax/To (=b/aL, L is the length of the muscle) was not affected. The value of vmax/To was 1.14±0.22 x 10_b cm2/(dyn . sec) (mean±S. D. in 9 rabbits). The constants A and B/V, especially A, increased and the ratio vmax/To decreased under the negative inotropic effect, such as decreased heart rate or decreased coronary perfusion pressure. This ratio would therefore be a good indicator for assessment of the ventricular performance as well as the contractility of the wall muscle.

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“…b) Force-load-velocity relation of the contractile component. In the previous paper (MASHIMA et al, 1972 …”

Section: Summary1)mentioning

confidence: 94%

“…According to MASHIMA et al (1972), Fv(t) is a hyperbolic function of the velocity and at the same time it is a linear function of the force. It is reasonable to assume that F(t) is nothing but the intensity of the active state which is defined by HILL (1949) as the intrinsic strength of the contractile component, because F(t) is a time course of the force-generating capability of the contractile component.…”

Section: Summary1)mentioning

confidence: 99%

Graphical Analysis and Experimental Determination of the Active State in Frog Skeletal Muscle

et al. 1973

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The Force-Load-Velocity Relation and the Viscous-Like Force in the Frog Skeletal Muscle

Abstract: SummaryThe load-velocity relations were determined at various contractile forces in the small bundle dissected from frog semitendinosus muscle.

Cited by 77 publications

References 19 publications

Depressive effects of active shortening on stoke volume of left ventricle and shortening amount of isolated ventricular muscle.

Depressive effects of active shortening on stoke volume of left ventricle and shortening amount of isolated ventricular muscle.

Pressure-velocity relation in the isolated rabbit left ventricle.

Graphical Analysis and Experimental Determination of the Active State in Frog Skeletal Muscle

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