Role of Acetylstrophanthidin in Augmenting Myocardial Oxygen Consumption

Coleman, Henry Neal

doi:10.1161/01.res.21.4.487

Cited by 60 publications

(18 citation statements)

References 25 publications

(30 reference statements)

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“…The average cross-sectional area of the papillary muscles in this study was larger than optimum and some degree of hypoxia may wvell have been present (16)(17)(18). Although the use of smaller papillary muscles would have been desirable, it is extremely difficult to obtain a large number of such muscles in banded cats.…”

Section: Contractile State Of Hypertrophied Myocardium 1269mentioning

confidence: 73%

Normal Contractile State of Hypertrophied Myocardium after Pulmonary Artery Constriction in the Cat

Williams¹,

Potter²

1974

J. Clin. Invest.

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A B S T R A C T The contractile function of right ventricular papillary muscles from normal cats and cats in which the pulmonary artery had been constricted for 6 or 24 wk was examined. Acute pulmonary artery constriction reduced cross-sectional area by an average of 70%, resulting in a 30% mortality from congestive heart failure, all such deaths occurring within the first 3 wk after banding. The increase in right ventricular mass in animals surviving for 6 or 24 wk was similar, averaging 70%. No banded animals had evidence of congestive heart failure at the time of sacrifice, and cardiac output and right atrial pressures were similar to those in control animals.6 wk after banding, the active length-tension curve, maximal rate of rise of isometric force, force-velocity relations, and isometric force with paired stimulation and norepinephrine were all significantly depressed when compared to their respective values in control animals. In contrast, none of these variables was significantly different from control values in animals banded for 24 wk. These observations indicate that depressed contractile state is not a fundamental characteristic of pressureinduced hypertrophied myocardium and reemphasize the important temporal relationship between contractile state and the imposition of sudden sustained loads.

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Section: Contractile State Of Hypertrophied Myocardium 1269mentioning

confidence: 73%

Normal Contractile State of Hypertrophied Myocardium after Pulmonary Artery Constriction in the Cat

Williams¹,

Potter²

1974

J. Clin. Invest.

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“…Thus Gibbs [2], using the Na ϩ -flux data of McCall [146] for the rat heart, calculated that the basal demand of the Na ϩ -pump could be as high as 4 mW g Ϫ1 in that species. An earlier experimental study, in which pharmacological inhibition of the pump was achieved in papillary muscles while the rate of heat production was being measured [93], returned null results. That is, the anticipated diminution of heat rate did not eventuate.…”

Section: Contributors To the Energymentioning

confidence: 97%

Cardiac Basal Metabolism.

Gibbs

Loiselle²

2001

JJP

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The cardiac basal metabolism is the rate of energy expenditure of the quiescent myocardium. It is also called the resting metabolism or the arrested heart metabolism. It has been measured in numerous ways, and in vivo there is good evidence that it accounts for about 1/5 to 1/3 of the total energy flux. The difficulty arises, however, when the heart is stopped because the magnitude of the basal metabolism depends, as blood viscosity, on how and under what physiological condition it is measured. It is possible for the in vivo basal value to fall to less than 1/5 of its original value without cellular damage or to increase to values 5 times greater than its probable in vivo magnitude (i.e., to rise to values in excess of the energy flux of the normally beating heart) by altering the composition of the perfusion medium. We have written on this subject several times [1][2][3], but believe that developments in knowledge now make it possible for us to speculate in a more informed manner. Since several million openheart operations are performed on arrested hearts worldwide each year, it would seem imperative that we understand the cellular mechanisms that can change the magnitude of basal metabolism.A. V. Hill [4] has pointed out that in examining physiological activities, it is necessary to assume a baseline from which some quantity or rate can be measured. If the energy flux produced by the beating heart were very large compared with the energy flux of the arrested heart, baseline ambiguity would be relatively unimportant. But this is not so in regard to the heart; its basal metabolism is high. Within a species, the basal metabolism of cardiac tissue is several-fold higher than the resting metabolism of skeletal muscle and is an order of magnitude greater than the resting metabolism of amphibian skeletal muscle.Species differences are clearly evident in the magnitude of cardiac basal metabolism, and we believe that the major reason for these differences relates to the leakiness of cell membranes, such as those of the sarcolemma and sarcoplasmic reticulum and those of Japanese Journal of Physiology, 51, 399-426, 2001 Key words: whole hearts, isolated preparations, biochemical contributors, modifiers, species difference, temperature, substrate, hypoxia. Abstract:We endeavor to show that the metabolism of the nonbeating heart can vary over an extreme range: from values approximating those measured in the beating heart to values of only a small fraction of normal-perhaps mimicking the situation of nonflow arrest during cardiac bypass surgery. We discuss some of the technical issues that make it difficult to establish the magnitude of basal metabolism in vivo. We consider some of the likely contributors to its magnitude and point out that the biochemical reasons for a sizable fraction of the heart's basal ATP usage remain unresolved. We consider many of the physiological factors that can alter the basal metabolic rate, stressing the importance of substrate supply. We point out that the protective effect of hypothermia ...

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“…The top of the muscle is attached to the lever of a displacement measurement and control system. This figure has been revised from one showing an earlier version of this polarographic myograph (19).…”

Section: Mechanical and Energetic Measurementsmentioning

confidence: 99%

“…This assumption is based on the aerobic nature of myocardial respiration (15) and on the use ofa properly designed flow respirometer to study a stable muscle preparation. This flow respirometer was designed from well-defined criteria ( 16); these criteria have been used in the study of papillary muscle respiration in several older (17)(18)(19) and more recent (13,14) investigations. The characteristics of this respirometer are as follows: the central tubular muscle chamber is 41 mm long and 3.5 mm wide, and has a volume of 0.4 ml; the sampling capillary at the bottom of the muscle chamber is 0.8 mm in diameter, with the oxygen cathode 39 mm distal to its origin; the superfusate flow rate past the muscle and then through this capillary is 6.25 ml/h.…”

Section: Mechanical and Energetic Measurementsmentioning

confidence: 99%

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Beta adrenergic receptor blockade of feline myocardium. Cardiac mechanics, energetics, and beta adrenoceptor regulation.

Th¹,

Kent²,

McGonigle³

et al. 1986

J. Clin. Invest.

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assessed and controlled; second, to define the effects of this intervention on myocardial energetics in terms of any changes dependent on or independent ofalterations ofthese determinants of MVO2; third, to define any change in myocardial sensitivity to catecholamine action after the withdrawal of long-term (3-adrenoceptor blockade; fourth, to determine whether chronic f3-adrenoceptor blockade alters the number, affinity, or biochemical activity of this autonomic receptor. MethodsFour separate series ofexperiments, each employing paired sets ofcontrol and chronically ,8-blocked cats, comprise the data base for this study. In the first series, mechanical and metabolic behavior of myocardium isolated from these two sets of cats was measured. In the second series, the specific relationship of any differences found between these two sets of animals to changes in the activity of the cardiac fl-adrenoceptor was examined. In the third series, the effect ofchronic fl-adrenoceptor blockade on fl-adrenoceptor number, affinity, and affinity state was assayed. In the fourth series, the effect of chronic fl-adrenoceptor blockade on the major immediate U-mediated biochemical response, cyclic AMP generation, was determined. Experimental animalsThe animals used were 1.7-3.6-kg adult cats of random sex. The cats in the control groups received normal saline (I cm3/kg i.p.) twice daily for 14 d prior to study. The chronically fl-blocked cats were prepared and characterized as follows. First, their baseline responsiveness to (3-adre-

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Role of Acetylstrophanthidin in Augmenting Myocardial Oxygen Consumption

Cited by 60 publications

References 25 publications

Normal Contractile State of Hypertrophied Myocardium after Pulmonary Artery Constriction in the Cat

Normal Contractile State of Hypertrophied Myocardium after Pulmonary Artery Constriction in the Cat

Cardiac Basal Metabolism.

Beta adrenergic receptor blockade of feline myocardium. Cardiac mechanics, energetics, and beta adrenoceptor regulation.

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