CARDIOTONIC ACTIVITY OF CERTAIN STEROIDS AND BILE SALTS

1952 ◽  
Vol 30 (4) ◽  
pp. 325-332 ◽  
Author(s):  
J. S. Loynes ◽  
C. W. Gowdey
Keyword(s):  
Heart Rate ◽  
Steroid Hormones ◽  
Coronary Flow ◽  
Bile Salts ◽  
Lactone Ring ◽  
Water Soluble ◽  
Force Of Contraction ◽  
Cardiotonic Activity ◽  
Cardiotonic Action ◽  
Significant Augmentation

The effects of 23 plant and animal steroids, steroid hormones, and bile acids, and nine of their salts or soluble conjugates, have been investigated in isolated frog hearts. All but five of the compounds produced significant augmentation of frog hearts made hypodynamic by prolonged perfusion. The augmentation was not usually accompanied by changes in heart rate, and no steroid caused systolic arrest. Eight water-soluble steroid salts were perfused through isolated rabbit hearts when they had become hypodynamic by prolonged perfusion. In each case the coronary flow increased significantly whether the heart rate and force of contraction increased or not. Thus, when cardiotonic activity was observed, it appeared to be a direct effect and not secondary to the increased coronary flow. It would seem that the lactone ring of the cardiac glycoside molecule is responsible for the development of systolic arrest, and that the cardiotonic action is, at least partly, a function of the cyclopentenophenanthrene nucleus.

The Effects of Increase in Heart Rate on Coronary Flow Reserve and Flow Profiles : A Study with Intracoronary Doppler wire

1995 ◽  
Vol 25 (6) ◽  
pp. 1091
Author(s):  
Han-Soo Kim ◽  
Seung-Jea Tahk ◽  
Joon-Han Shin ◽  
Yun-Kyung Cho ◽  
Won Kim ◽  
...  
Keyword(s):  
Heart Rate ◽  
Coronary Flow Reserve ◽  
Coronary Flow ◽  
Intracoronary Doppler ◽  
Flow Reserve ◽  
Flow Profiles

Relation of coronary flow to oxygen supply

1960 ◽  
Vol 199 (1) ◽  
pp. 179-182 ◽  
Author(s):  
Abraham Guz ◽  
George S. Kurland ◽  
A. Stone Freedberg
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Oxygen Content ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Rabbit Heart ◽  
Hemoglobin Solution ◽  
Oxygen Capacity ◽  
Locke Solution ◽  
Solution Change

Coronary flow, heart rate, myocardial oxygen consumption and Walton strain gauge tension were determined in the isolated rabbit heart perfused with hemoglobin solutions of varying oxygen content. Perfusion was carried out under constant pressure and with the hemoglobin solution in equilibrium with 3% CO2 and 97% air under atmospheric tension. Oxygen content was varied from 2 to 18 vol. % by diluting hemoglobin with Ringer-Locke solution. Change from a higher to lower oxyhemoglobin concentration resulted in increased coronary flow; the reserve led to decreased flow. Heart rate, myocardial tension and oxygen consumption were constant at oxygen capacity above 2 vol. %.

Glucose metabolism in perfused mouse hearts overexpressing human GLUT-4 glucose transporter

2001 ◽  
Vol 280 (3) ◽  
pp. E420-E427 ◽  
Author(s):  
Darrel D. Belke ◽  
Terje S. Larsen ◽  
E. Michael Gibbs ◽  
David L. Severson
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Fatty Acid ◽  
Coronary Flow ◽  
Glucose Oxidation ◽  
Glucose Transporter ◽  
Acid Metabolism ◽  
Glut 4 ◽  
Cardiac Power ◽  
Glycolytic Rate

Glucose and fatty acid metabolism was assessed in isolated working hearts from control C57BL/KsJ- m+/+db mice and transgenic mice overexpressing the human GLUT-4 glucose transporter ( db/+-hGLUT-4). Heart rate, coronary flow, cardiac output, and cardiac power did not differ between control hearts and hearts overexpressing GLUT-4. Hearts overexpressing GLUT-4 had significantly higher rates of glucose uptake and glycolysis and higher levels of glycogen after perfusion than control hearts, but rates of glucose and palmitate oxidation were not different. Insulin (1 mU/ml) significantly increased glycogen levels in both groups. Insulin increased glycolysis in control hearts but not in GLUT-4 hearts, whereas glucose oxidation was increased by insulin in both groups. Therefore, GLUT-4 overexpression increases glycolysis, but not glucose oxidation, in the heart. Although control hearts responded to insulin with increased rates of glycolysis, the enhanced entry of glucose in the GLUT-4 hearts was already sufficient to maximally activate glycolysis under basal conditions such that insulin could not further stimulate the glycolytic rate.

Mechanisms of antifibrillatory effect of acidic reperfusion: role of perfusate bicarbonate concentration

1993 ◽  
Vol 264 (3) ◽  
pp. H783-H790 ◽  
Author(s):  
C. Ibuki ◽  
D. J. Hearse ◽  
M. Avkiran
Keyword(s):  
Heart Rate ◽  
Ventricular Fibrillation ◽  
Rat Heart ◽  
Coronary Flow ◽  
Isolated Rat Heart ◽  
Acidic Ph ◽  
Bicarbonate Concentration ◽  
Left And Right ◽  
Isolated Rat

Transient (2 min) acidic (pH 6.6) reperfusion with low [HCO3-] solution suppresses reperfusion-induced ventricular fibrillation (VF) in the isolated rat heart. Using this preparation, we tested whether the effect was mediated by the high [H+] or the low [HCO3-] of perfusate. Left and right coronary beds were independently perfused with HCO3(-)-containing (25.0 mmol/l) solution at pH 7.4. Regional ischemia was then induced by stopping flow to the left coronary bed for 10 min. Hearts were subsequently assigned to four groups (n = 12 hearts/group), and the left coronary bed was reperfused with either HCO3(-)-containing (25.0 or 4.0 mmol/l) or HCO3(-)-free (5.0 mmol/l HEPES) solution, at pH 7.4 throughout (control reperfusion) or at pH 6.6 for the first 2 min and at pH 7.4 from 2 to 5 min (acidic reperfusion). Regardless of the buffer, controls exhibited a high (92 and 100%) incidence of VF; this was reduced to 42% in both of the acidic reperfusion groups (P < 0.05). There were no intergroup differences in heart rate, coronary flow, or size of ischemic zone. Thus high [H+], rather than low [HCO3-], appears to mediate the antifibrillatory effect of transient acidic reperfusion.

Effects of oral perhexiline on canine myocardial flow distribution

1980 ◽  
Vol 58 (5) ◽  
pp. 543-549 ◽  
Author(s):  
Gerald A. Klassen ◽  
Danuta T. Zborowska-Sluis ◽  
George J. Wright
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Heart Rate ◽  
Linear Relationship ◽  
Mechanism Of Action ◽  
Coronary Flow ◽  
Flow Distribution ◽  
Perhexiline Maleate ◽  
Myocardial Flow ◽  
Infarction Heart

Perhexiline maleate at a dose of 400 mg three times daily for 2 days administered to normal dogs altered the relative regional transmural resistance so that during reduced coronary flow the endocardium:epicardium (endo:epi) ratio is increased. In the presence of acute myocardial infarction heart rate was significantly lower and the endo:epi ratio of perfused areas was increased when coronary flow was normal. A linear relationship was observed between the endo:epi ratio and the concentration of perhexiline in plasma, and its monohydroxyl metabolite in plasma. The results suggest that the mechanism of action of the drug is due to redistribution of a limited coronary flow.

Spinal action of neurokinins in the rat: effects on mean arterial pressure, heart rate, and vascular permeability

1987 ◽  
Vol 65 (11) ◽  
pp. 2182-2187 ◽  
Author(s):  
Harout Hasséssian ◽  
Réjean Couture ◽  
Line Jacques
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Permeability ◽  
Cardiovascular Responses ◽  
Intrathecal Administration ◽  
Water Soluble ◽  
Neurokinin A ◽  
Anaesthetized Rats

In urethane-anaesthetized rats, the intrathecal administration of 6.5 nmol of substance P (SP), neurokinin A (NKA), or neurokinin B (NKB) at the T8–T10 level of the spinal cord enhances mean arterial pressure and heart rate. However, in the pentobarbital-anaesthetized rat, while NKB produces no effect on mean arterial pressure, NKA produces a biphasic change and SP, a depressor response. All three neurokinins elicit a tachycardia. The following rank order of potency SP ≥ NKA > NKB is observed in relation to these cardiovascular responses when either one of the two anaesthetics is used. The low cardiovascular activity of NKB cannot be attributed to its hydrophobicity, as the water soluble analogue of NKB, [Arg0] NKB, elicits a response as weak as the native peptide. In pentobarbital-anaesthetized rats, the intrathecal administration of 6.5 nmol of SP, also enhances plasma protein extravasation in cutaneous tissues of the back, the hind paws, and the ears. In this response NKA and NKB are either inactive (skin of hind paws) or less potent than SP (ears and dorsal skin). These findings agree with the hypothesis that in the rat spinal cord, the neurokinin receptor producing changes in mean arterial pressure, heart rate, and vascular permeability is of the NK-1 subtype.

Effect of Acetaldehyde on the Isolated, Non-working Guinea-Pig Heart: Independence of the Coronary Flow Increase from Changes in Heart Rate and Oxygen Consumption

1974 ◽  
Vol 52 (3) ◽  
pp. 602-612 ◽  
Author(s):  
Minh-Hau Nguyen ◽  
L. Gailis
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Gas Phase ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Guinea Pig Heart ◽  
Bicarbonate Buffer

Guinea-pig hearts were perfused at constant pressure with Krehs–Henseleit bicarbonate buffer equilibrated with 95% O2 – 5% CO2. Acetaldehyde at 1 and 5 mM increased coronary flow, oxygen consumption, and heart rate. At 0.2 mM, it increased coronary flow and oxygen consumption only. In the rapidly paced heart, 1 mM acetaldehyde increased coronary flow, but not heart rate or oxygen consumption. Acetaldehyde increased coronary flow and oxygen consumption of the potassium-arrested heart. Acetaldehyde increased all parameters of the hypoxic heart (25% O2 gas phase), but the anoxic heart was not affected (coronary flow was already maximal).Reserpine (in vivo) and catecholamine β blockers (dichloroisoproterenol and propranolol) (in vitro) blocked the heart rate increases and moderated the rise in oxygen consumption. Dichloroisoproterenol plus phentolamine blocked the increases of both heart rate and oxygen consumption. None of the compounds affected the increase of coronary flow produced by acetaldehyde. Epinephrine, norepinephrine, and tyramine increased the heart rate and oxygen consumption, but not the coronary flow. Theophylline increased all three parameters. Neither tranylcypromine nor atropine modified the acetaldehyde effect. We conclude that the increase in heart rate is mediated by catecholamine β receptors. The increase in coronary flow is independent of the increase in heart rate or oxygen consumption and is not mediated by catecholamines.

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