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  • Blood-pH  (1)
  • Cardiovascular Effects  (1)
  • Endothelium-dependent relaxation  (1)
  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Differences in acetylcholine- and bradykinin-induced vasorelaxation of the mesenteric vascular bed in spontaneously hypertensive rats of different ages (1996)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 38-43 
    Details
    ISSN: 1432-1912
    Keywords: Key words SHR ; Endothelium-dependent relaxation ; Rat mesenteric vascular bed ; Rat thoracic aorta ; Bradykinin Acetylcholine ; Age dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The present study examined whether alterations of endothelium-dependent vasorelaxation in spontaneously hypertensive rats (SHR) in response to the endothelium-dependent vasodilators acetylcholine and bradykinin ran parallel. We tried to find out the age at which endothelium-dependent vasorelaxation in response to each agonist became impaired and compared three different groups of SHR aged 7, 21 and 51 weeks. To be able to separate hypertension-induced alterations from age-dependent changes age-matched normotensive Wistar rats were included. Endothelium-dependent vasorelaxation was studied in the mesenteric vascular bed precontracted with noradrenaline, a typical resistance vessel, which showed relaxation to both acetylcholine and bradykinin, and the precontracted thoracic aorta, which only responded to acetylcholine. There were major differences in the agonist-dependent vasorelaxation between bradykinin and acetylcholine in SHR as a function of age. A surprising finding was that acetylcholine-induced relaxation was preserved, even slightly improved not only in young SHR (7 weeks) with developing hypertension but also in adult SHR (21 weeks) with established hypertension, which can be interpreted as a compensatory mechanism. As expected, in old SHR (51 weeks) acetylcholine-induced vasorelaxation was impaired as a consequence of the detrimental effects of long-term hypertension on endothelium. The parallel changes observed with acetylcholine in the mesenteric vascular bed and thoracic aorta provided mutual confirmation. In clear contrast to acetylcholine bradykinin-induced vasorelaxation was already impaired in young SHR with developing hypertension suggesting that bradykinin-induced vasorelaxation is either much more sensitive to detrimental effects of (even slightly) increased blood pressure or, more likely, that there is a basic deficiency in the action of bradykinin in SHR. Thus, our study allows to conclude that impairment of acetylcholine-induced endothelium-dependent vasorelaxation in the mesenteric vascular bed of SHR is a secondary phenomenon developing as a consequence of long-term hypertension while the impaired bradykinin-induced vasorelaxation seems to be a primary phenomenon that could be closely related to the development of hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00168704
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    Paper (German National Licenses)
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  • 3
    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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    Paper (German National Licenses)
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