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  • 1
    Electronic Resource
    Electronic Resource
    Über den Einfluß der extracellulären Wasserstoffionenkonzentration auf die Wirkung kreislaufaktiver Pharmaka (1971)
    Springer
    Clinical and experimental medicine 154 (1971), S. 165-176 
    Details
    ISSN: 1591-9528
    Keywords: Blood-pH ; resp. Acidosis ; Cardiovascular Drugs ; Blut-pH ; resp. Acidose ; kreislaufaktive Pharmaka
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Elektrisch gereizte Vorhofpräparate des Meerschweinchens wurden in einem Tyrodebad suspendiert, dessen pH durch Begasung mit verschiedenen CO2-Konzentrationen auf 7,0, 7,4 bzw. 7,8 eingestellt wurde. Kontraktionskraft und maximale Kontraktionsgeschwindigkeit der Vorhöfe wurden durch diese pH-Änderungen nicht beeinflußt. Der positiv inotrope Effekt von Tyramin, Isoproterenol und Calcium war bei pH 7,0 abgeschwächt, bei pH 7,8 verstärkt. An narkotisierten Katzen wurde durch Beatmung mit 10 bzw. 20% CO2 eine respiratorische Acidose mit pH-Werten von 7,15 bzw. 7,0 erzeugt. Dabei traten eine mäßige Zunahme der Herzfrequenz, der maximalen Druckanstiegsgeschwindigkeit (dp/dtmax) und des systolischen Femoralisdruckes ein. Die Wirkung aller untersuchten Pharmaka war in Acidose abgeschwächt, wobei sich aber folgende quantitative und qualitative Unterschiede ergaben: 1. Die blutdrucksenkende Wirkung des Isoproterenols und die blutdrucksteigernde Wirkung des Noradrenalins waren stärker abgeschwächt als ihre positiv inotrope Wirkung am Herzen. 2. Die pressorische Wirkung des Angiotensins und Noradrenalins war weniger beeinträchtigt als die des Naphazolins. 3. Die blutdrucksenkende Wirkung des Acetylcholins war im Gegensatz zu der des Isoproterenols weniger abgeschwächt.
    Notes: Summary Experiments were performed on guinea pigs isolated atria which were stimulated electrically. If the pH of the tyrode solution was changed by variation of pCO2 no alteration of force of contraction and maximal velocity of contraction (dT/dtmax.) occured. The inotropic effects of tyramine, isoproterenol and calcium were diminished at pH 7.0 and increased at pH 7.8. During respiratory acidosis (pH 7.0) anaesthetized cats showed a small increase in heart rate, left ventricular dp/dtmax. and arterial blood pressure. The effects of all tested drugs were diminished in acidosis, whereby the following qualitative and quantitative differences appeared: 1. The depressive effect of isoproterenol and the stimulating effect of norepinephrine on arterial blood pressure were much more diminished than the positive inotropic effect of these drugs. 2. The effect of angiotensin and norepinephrine on arterial blood pressure was less affected than that of naphazoline. 3. The effect of acetylcholine on arterial blood pressure was scarcely diminished in contrast to that of isoproterenol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02048388
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  • 2
    Electronic Resource
    Electronic Resource
    Inhibition of calcium transport in mitochondria byβ-receptor blocking substances and its reactivation by phospholipids (1971)
    Springer
    Cellular and molecular life sciences 27 (1971), S. 810-811 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung β-Rezeptorenblocker hemmen den aktiven Kalziumtransport an isolierten Herzmitochondrien und den phospholipidvermittelten Kalziumtransport in Ausschüttelungsversuchen. Die Hemmung des mitochondrialen Kalziumtransportes lässt sich durch Phosphatidylserin und weniger stark durch Lecithin (≧10−4 g/ml) aufheben, während andere Phospholipide und deren Bausteine wirkungslos sind.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02136879
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of respiratory acidosis on heart and circulation in cats, pigs, dogs and rabbits (1972)
    Springer
    Research in experimental medicine 158 (1972), S. 308-320 
    Details
    ISSN: 1433-8580
    Keywords: Respiratory Acidosis ; Cardiovascular Effects ; Sympathomimetic Amines ; Species Differences ; Respiratorische Acidose ; Kreislauf ; Sympathomimetica ; Speciesunterschiede
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Katzen, Hunden, Kaninchen und Hausschweinen wurden in Pentobarbitalnarkose nach Muskelrelaxation mit Alloferin® bei geschlossenem Thorax die Auswirkungen einer akuten respiratorischen Acidose auf den Kreislauf sowie dessen Reaktion auf Pharmaka untersucht. 1. BeiKatzen undSchweinen steigen in respiratorischer Acidose Herzfrequenz, dp/dtmax und Blutdruck an; beiKaninchen bleiben dp/dtmax und Blutdruck nahezu unverändert. BeiHunden hingegen sinken Schlagfrequenz, dp/dtmax und Blutdruck in Acidose ab. Untersuchungen an Katzen, die mit Reserpin vorbehandelt waren, zeigten, daß eine respiratorische Acidose einen negativ inotropen und blutdrucksenkenden Eigeneffekt besitzt. Nach Vorbehandlung mit Phenoxybenzamin verursacht eine respiratorische Acidose bei Katzen einen Blutdruckabfall sowie einen Anstieg von dp/dtmax. Nach Vorbehandlung mit Pindolol verursacht eine Acidose eine Abnahme von Frequenz und dp/dtmax, während der Blutdruck konstant bleibt. Am unvorbehandelten Tier wird der negativ inotrope Effekt einer Acidose offenbar durch eine Stimulierung des sympathischen Nervensystems überdeckt, die bei Katzen und Schweinen am ausgeprägtesten ist. 2. DieWirkung sympathomimetischer Amine auf Herz und Kreislauf ist bei allen 4 untersuchten Tierarten in Acidose abgeschwächt, wobei die Abschwächung bei den Tieren mit der stärksten sympathischen Stimulation am ausgeprägtesten ist. 3. Biochemische Untersuchungen an Hunden und Katzen ergaben, daß in Acidose K+, Mg2+, anorganisches Phosphat und Glucose im Serum ansteigen, während der Magnesiumgehalt des Herzmuskels abnimmt.
    Notes: Summary In closed chest cats, dogs, rabbits and pigs, anaesthetized with pentobarbital and relaxed with diallylnortoxiferinium dichloride the effects of a respiratory acidosis on heart and circulation as well as their reaction to sympathomimetic amines were studied. 1. Incats andpigs a respiratory acidosis causes a rise of frequency, dp/dtmax of the left ventricle and systolic blood-pressure. Inrabbits an acidosis causes no significant alteration of blood-pressure and dp/dtmax. Indogs frequency, dp/dtmax and blood-pressure decline in acidosis. In cats pretreated withreserpine a respiratory acidosis causes a negative inotropic effect and a declining of blood-pressure. After pretreating cats withphenoxybenzamine in acidosis there results a decrease of blood-pressure, but a rise of dp/dtmax and frequency; after pretreating withpindolol in acidosis dp/dtmax and frequency decline, but blood-pressure remains unaltered. 2. The effectiveness of sympathomimetic amines on heart and circulation is diminished in acidosis. This diminution is most significant in those animals (cat, pig) with the most augmented sympathetic tonus in acidosis, but experiments performed with reserpinized cats indicated that the augmented sympathetic tonus can not be the only cause for the diminished efficiency of adrenergic stimulant amines in acidosis. 3. Biochemical studies performed in acidosis showed a rise of K+, Mg2+, inorganic phosphate and glucose in serum and a decrease of Mg2+ in the heart muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852214
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  • 4
    Electronic Resource
    Electronic Resource
    The effects of isoprenaline and tyramine on the 45calcium uptake, the total calcium content and the contraction force of isolated guinea-pig atria in dependence on different extracellular hydrogen ion concentrations (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 274 (1972), S. 125-137 
    Details
    ISSN: 1432-1912
    Keywords: Sympathomimetic Amines ; pH ; 45Calcium Uptake ; Contraction Force ; Guinea-Pig Atria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Isolated, electrically stimulated left guinea-pig atria were incubated at 30° C in a Tyrode solution, the hydrogen ion concentration of which was varied by altering the percentage of the aerating CO2/O2-mixture. The increase of the extracellular hydrogen ion concentration from pH 8.0 to pH 7.0 caused a reduction of the 45calcium uptake and of the contraction force. The positive inotropic effect and the concomitantly occuring increased 45calcium uptake induced by isoprenaline and tyramine were markedly diminished at the lower pH, the response to tyramine being more affected by increased hydrogen ion concentration than that of isoprenaline. This is possibly due to a decrease in noradrenaline available at pH 7.0 for release by tyramine. Isoprenaline and tyramine enhanced the relative specific 45calcium activity (RSA) without altering the total tissue calcium content. On the contrary, the increase of the extracellular calcium concentration caused an augmentation of the relative specific 45calcium activity and the total tissue calcium content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501847
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of k-strophanthin and digitoxigenin on contractile force, calcium content and exchange in guinea-pig isolated atria (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 275 (1972), S. 359-371 
    Details
    ISSN: 1432-1912
    Keywords: k-Strophanthin ; Digitoxigenin ; 45Calcium ; Contractile Force ; Cellular Calcium Content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of positive inotropic and of toxic concentrations of k-strophanthin and digitoxigenin on contractile force, calcium content and 45calcium exchange was studied in isolated guinea-pig atria; at the same time the extracellular space of each preparation was determined. 1. In the concentration range used (0.8–13.4 μM) the two agents did not show any effect on the extracellular space. 2. Positive inotropic concentrations of k-strophanthin and digitoxigenin induced a significant decrease in the cellular calcium content as a result of a net increase in calcium efflux. At 3, 5, 10 or 15 min after the addition of the drug the relative specific 45calcium activity (RSA) was increased and was significantly greater than values obtained in control experiments. It is concluded that positive inotropic concentrations enlarge the exchangeable calcium fraction of the myocardial cell. 3a. During the initial positive inotropic phase of action of toxic concentrations of k-strophanthin (2.67 and 13.4 μM) and digitoxigenin (2.67 μM) there was also a significant decrease of the cellular calcium content, which occured more rapidly than that produced by positive inotropic concentrations. 3b. After the occurrence of toxic signs the calcium content of the myocardial cell was significantly increased while the unexchanged calcium fraction remained unchanged in absolute size. The RSA was always significantly increased compared with results from control experiments. It is concluded that the action of toxic concentrations of k-strophanthin and digitoxigenin on the calcium metabolism is due to a marked reduction in calcium efflux. 4. Digitoxigenin increased the contractile force considerably more than k-strophanthin, but had less effect on calcium metabolism. The difference might be due to the different lipophilic properties of the two agents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501125
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