A Study of Inotropic Mechanisms in the Papillary Muscle Preparation

Abbott, B. C.; Mommaerts, W. F. H. M.

doi:10.1085/jgp.42.3.533

Cited by 315 publications

(117 citation statements)

References 7 publications

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“…The behaviour of the taenia was different from that of skeletal muscle (Hill, 1951-2) and uterine muscle (Csapo & Goodall, 1954;Kuriyama, 1961), in that the peak of active tension did not occur at zero resting tension and was ill-defined. In this respect the taenia resembled the papillary muscle of the heart (Abbott & Mommaerts, 1959).…”

Section: Discussionmentioning

confidence: 81%

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

Bülbring¹,

Kuriyama²

1963

The Journal of Physiology

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The relaxation of intestinal smooth muscle by adrenaline is due to the cessation of the spontaneous discharge of action potentials which is associated with a rise in membrane potential (Biulbring, 1955;Burnstock, 1958). The magnitude of the hyperpolarization depends on the membrane potential prevailing at the moment when adrenaline is applied (Biilbring & Kuriyama, 1963). Though it is known that the membrane potential is related to the degree of stretch applied to the muscle it has not been possible in the past to set it with regularity at a certain level in different preparations, because the definition of the initial muscle length has been inadequate. Resting length cannot be determined because spontaneous activity prevents complete relaxation. In situ length depends on the spontaneous tone at the moment of excision. Thus preparations of equal in situ length, mounted at a certain length or at a certain tension, behave quite differently.The relation between muscle length and muscle tension is complicated by the active production of tension in response to stretch, which prevents the distinction between resting and active tension, the latter being an unknown fraction of the total tension recorded. On the other hand, tension is related to the cross-sectional area of the muscle. When the muscle is stretched, the deformation of the muscle fibres can be measured not only by the increase in length but also by the reduction in cross-sectional area. An estimate of this is given by the ratio of muscle weight (mg) to its length (mm). The W:L ratio takes into account the variable weight of different muscles, and thus it would be expected to provide the standard conditions required for the comparison of different preparations.In the present work reproducible conditions have been obtained by stretching the muscle to a given length in relation to its weight. Within certain limits the initial membrane potential as well as the changes produced by adrenaline were found to be proportional to the W:L ratio.

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Section: Discussionmentioning

confidence: 81%

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

Bülbring¹,

Kuriyama²

1963

The Journal of Physiology

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“…31 3 The applicability of the force-velocity-length relation to cardiac tissue has been confirmed by studies performed on the intact hearts of anesthetized animals34' 3 and in human subjects in whom roentgen-opaque markers had been sutured to the ventricles during cardiac surgery. 36 Several indices of contractility have been described using data obtained by left heart catheterization in intact human subjects.37 41 The present study was undertaken to determine the relationships, in normal and diseased hearts, between systolic time intervals and direct measurements of myocardial contractility obtained by invasive technics.…”

Section: Ahmed Et Almentioning

confidence: 98%

Systolic Time Intervals as Measures of the Contractile State of the Left Ventricular Myocardium in Man

Ahmed¹,

Levinson²,

Schwartz³

et al. 1972

Circulation

230

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SUMMARYPrevious studies relating systolic time intervals and measures of cardiac performance have suggested that the time intervals may be useful indices of myocardial contractility. To explore this possibility, systolic times and left ventricular (LV) performance and contractility were measured nearly simultaneously in 14 normal subjects and 56 patients with cardiac disease. Preejection period (PEP) and the ratio of PEP to LV ejection time (LVET) changed significantly with acute inotropic influences (exercise and isoproterenol), were normal in patients with right or left ventricular overloads in whom cardiac index and ejection fraction were depressed but contractile element velocity at peak dP/dt and the Frank-Levinson contractility index were normal, and were significantly abnormal in patients with either clinically evident or occult LV decompensation in whom the measures of contractility were reduced. Correlations of PEP and PEP/LVET with measures of both performance and contractility were insignificant for patients with valvular disease, shunts, or cor pulmonale and significant but weak for the entire series. However, in subjects with either normal left ventricles or cardiac disease confined to the left ventricle, PEP and PEP/LVET exhibited good correlations with measures of pump function and excellent correlations with measures of contractility. These results indicate that the systolic times are a valid measure of contractility which should prove useful in comparing patients with cardiac pathology confined to the LV myocardium and in following patients with extramyocardial hemodynamic lesions of constant severity.

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“…When the muscle moves against a load (force) through a given distance (space) work is produced, and the contractile potency is represented by the velocity of production of that work. Hill's ideas were confirmed by mathematical equations and subsequently supported by Abbott and Mommaerts 29 , with regards to its applicability to the human myocardium. Meanwhile, Abbott and Mommaerts called attention to the fact that the myocardium has a higher resting tension, contracts more slowly and cannot be tethanized…”

mentioning

confidence: 84%

The greatest medical discovery of the millennium (Fundamental steps to the understanding of cardiac performance)

Gottschall¹

1999

Arq. Bras. Cardiol.

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A Study of Inotropic Mechanisms in the Papillary Muscle Preparation

Cited by 315 publications

References 7 publications

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

The effect of adrenaline on the smooth muscle of guinea‐pig taenia coli in relation to the degree of stretch

Systolic Time Intervals as Measures of the Contractile State of the Left Ventricular Myocardium in Man

The greatest medical discovery of the millennium (Fundamental steps to the understanding of cardiac performance)

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