Protein synthesis in isolated,beating rat atria

Zusammenfassung Untersuchungen über die Proteinsynthese am isolierten, spontan schlagenden Rattenherzvorhof ergeben einen linearen Syntheseverlauf während mehrerer Stunden bei relativ normalem Energieverbrauch des Gewebes. Die Einbaugeschwindigkeit des Leuzins in das Gesamtprotein des Vorhofs ist höher als bei anderen untersuchten Geweben.

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Recipient of a Research Career Development Award No. 1-K3-HE-17, 885, from the U.S. Public Health Service.     

Effect of synthetic vasopressins on the myocardial contractile force in the isolated guinea-pig atria

Zusammenfassung Niedrige Dosen von 8-Arginin Vasopressin, 2-Phenylalanin-8-Lysin Vasopressin und 8-Lysin Vasopressin (unter 10 mU/ml), haben keinen Einfluss auf die Myokardkontraktion des isolierten Meerschweinchen-Atriums. Grössere Dosen dieser Peptide (über 20 mU/ml), führen zu einer dosisabhängigen Kontraktionsverminderung.     

Interrelationships between the contractile effects of metabolic substrates,β-adrenergic blocking agents and endogenous catecholamine depletion on isolated rat atria

Résumé La réduction de l'amplitude de la tension contractile auriculaire produite par ledl-propanolol ou par le MJ 1999 ne peut être considérée uniquement comme une conséquence du blocage des récepteurs-adrénergiques. D'autre part, l'action inotropique des drogues citées est nettement différente suivant que les oreillettes se trouvent dans un milieu contenant de la glucose ou du pyruvate. La dépression contractile provoquée par l'agrégat du pyruvate fut nettement moindre dans les oreillettes déplétionées de cathécholamines ou en présence dedl-propanolol ou du MJ 1999.

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A. L.Gimeno, M. F.Gimeno, E. A.Savino and A. S.Bedners, Proc. Soc. exp. Biol. Med.123, 875 (1966).     

Postnatal development of adrenergic and cholinergic sensitivity in the isolated rat atria

Summary The sensitivity to adrenergic drugs in isolated rat atria increased with the postnatal development. The cholinergic chronotropic sensitivity did not further change after birth.     

Postnatal development of adrenergic and cholinergic sensitivity in the isolated rat atria

The sensitivity to adrenergic drugs in isolated rat atria increased with the postnatal development. The cholinergic chronotropic sensitivity did not further change after birth.     

Quantitative changes in beta-adrenergic responses of isolated atria from hyper- and hypothyroid rats

Concentration-response curves for the chronotropic and inotropic effects of isoprenaline, in the absence and presence of propranolol, were obtained on heart atria isolated from normo- or dysthyroid rats. Hyperthyroidism increased the chronotropic potency and efficacy of the beta-adrenergic agonist. The results are compatible with the view that thyroid hormone increases the density of functional beta-adrenoceptors in cardiac pacemaker tissue.     

Stimulating effect of thromboxane B2 on isolated rat atria

Summary Thromboxane B₂ enhanced the beating frequency and the contractile tension of isolated rat atria. Both effects were inhibited by propranolol, by pretreatment with 6-hydroxydopamine, or after inhibition of prostaglandins synthesis with indomethacin and acetylsalicylic acid.This work has been supported by grant 6638 from CONICET (Argentina).     

The effects of oxamate on the contractility of isolated rat atria

Zusammenfassung Oxamat, das die Lactat-Dehydrogenase hemmt, erniedrigt die Kontraktionsfähigkeit des Vorhofs mit und ohne Anwesenheit von Glucose im Medium und bei Hinzufügung von 2-DG oder Atropin. Hohe Konzentration von Pyruvat erhöht die Depression von Oxamat auf den Vorhof im Glucose-Milieu. Oxamat sensibilisiert das Gewebe für funktionellen Abbau durch Glycolyse.

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This research was supported by grants No. 1441 and No. HE-994801 from Consejo Nacional de Investigaciones de la República Argentina, and from the National Institute of Health, respectively.

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Research Fellow from the Consejo Nacional de Investigaciones de la República Argentina.

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Established Investigator from the Consejo Nacional de Investigaciones de la República Argentina.     

Effect of nicotine on the transmembrane potential and contractility of isolated rat atria

Zusammenfassung Die Wirkungen von Nikotin auf die Kontraktilität und die Membranpotentiale des Rattenatriums wurden untersucht. Nikotin (5 × 10^–4 M) erhöhte gleichzeitig die entwickelte Spannung sowie die Dauer und Fläche des Aktionspotentials. Ein möglicher Zusammenhang dieser Änderungen mit der erhöhten Kontraktilität wird diskutiert.

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Deceased 22 July 1966.     

Effect of medium pH onp-aminohippurate accumulation by slices of rat renal cortex

Zusammenfassung Nierenschnitte von verschiedenen Arten akkumulieren PAH mit zunehmendem pH-Wert des Mediums bei einem deutlichen Maximum zwischen pH 7.4 und pH 8.0

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Supported in part by USPHS grant No. AM-10913.

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USPHS predoctoral trainee (GM-01761).

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Predoctoral Fellow of the Canadian Food and Drug Directorate, Ottawa.     

Prostaglandin-mediated contractile effect of impromidine and dimaprit in the isolated rat stomach fundus

Summary Impromidine and dimaprit, two newly-synthesized histamine H₂-receptor agonists, have been shown to produce a prostaglandin-mediated contraction in the isolated rat stomach fundus.Acknowledgments. Impromidine and dimaprit were generous gifts from Smith Kline and French Laboratories, Herts, England. This work was supported by a grant from Turkish Scientific and Technical Research Council (TAG-350).     

The influence of prostacyclin (PGI2) on contractile properties of isolated right ventricle of rat heart

The mechanism of the positive inotropic effect of prostacyclin (PGI₂) (2.6×10^?6 mol/l) on the isolated right ventricle of rat heart was studied. Our results show that the positive inotropic effect of prostacyclin is produced indirectly through beta adrenoceptors and slow Ca²⁺ channels, because blockade of slow Ca²⁺ channels with verapamil (10^?6 mol/l) and beta adrenoceptors with propranolol (10^?6 mol/l) abolishes this effect. Alpha adrenoceptors do not mediate the action of PGI₂.     

An adrenergic participation subserving a positive inotropism and chronotropism of prostacyclin on isolated rat atria

Summary The effects of prostacyclin (PGI₂) on the contractile frequency and on the isometric developed tension of spontaneously beating or paced isolated rat atria were explored. PGI₂ enhanced frequency and contractile tension, both effects being blocked by the presence of propranolol, or following a pretreatment with 6-OHDopamine.This work has been supported by Grant 6638 from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Effect of exercise training on the chronotropic response of isolated rat atria to atropine

Summary Atria isolated from rats after 7 weeks of exercise training beat at a slower rate than did atria from sedentary controls. Atria from exercised rats showed a significant acceleration in response to atropie.This study was supported by a grant from the Genesee Valley Heart Association.