Über die Abhängigkeit der Strophantinwirkung von der Intensität der Herztätigkeit

Weizsäcker, Viktor von

doi:10.1007/bf01890783

Cited by 37 publications

(13 citation statements)

References 2 publications

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“…As far as the onset of intoxication is concerned, at 2, 4 and 5 Hz again, a beat-dependence becomes obvious for the negative inotropic phase as well as for the increase in diastolic tension: the former being visible after about 3600, the latter beginning after roughly 5000 beats. A similar beat-dependence for the onset of toxicity has been demonstrated by Weizsacker (1913), Holland & Sekul (1961) and Gersmeyer & Holland (1963) (for review see Lee & Klaus, 1971).…”

Section: Discussionsupporting

confidence: 75%

“…The dependence of rate of onset of cardiac glycoside-induced intoxication upon beat frequency is well known and repeatedly documented (Weizsacker, 1913;Holland & Sekul, 1961). Weizsacker (1913) stated that the number of contractions rather than the time of incubation determine the onset of toxic effects after addition of ouabain in frog ventricular muscle. However, cardiac glycosides are not completely inactive in the resting heart and will produce contracture (Weizsacker, 1913).…”

Section: Introductionmentioning

confidence: 97%

“…Weizsacker (1913) stated that the number of contractions rather than the time of incubation determine the onset of toxic effects after addition of ouabain in frog ventricular muscle. However, cardiac glycosides are not completely inactive in the resting heart and will produce contracture (Weizsacker, 1913). Yet, contractile activity considerably enhances the onset of toxic signs.…”

Section: Introductionmentioning

confidence: 99%

“…Yet, contractile activity considerably enhances the onset of toxic signs. While the majority of investigators agree on a beat-dependent onset of toxicity (Weizsacker, 1913;Holland & Sekul, 1961;Gersmeyer & Holland, 1963) conflicting results are obtained with respect to a frequency-dependent rate of development of the cardiac glycoside-induced positive inotropism.…”

Section: Introductionmentioning

confidence: 99%

“…In consequence one may speculate that it is only at low temperatures and within a limited range of beat frequency that the development of positive inotropism can be correlated to the frequency of contraction. From the foregoing it is understandable that several investigators sought to gain more insight into the relation between beat frequency and molecular mode of action of cardiac glycosides by means of binding studies which can be considered to be a more direct approach (Weizsacker, 1913;RothSchechter, Anderson & Richardson, 1970;Deutscher, Harrison & Goldman, 1972). Unfortunately the experiments were carried out only with hydrophobic cardiac glycosides which are predominantly taken up by cardiac tissue in a nonspecific way, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Interdependence of Ion Transport and the Action of Ouabain in Heart Muscle

Bentfeld

Lüllmann

Peters

et al. 1977

British J Pharmacology

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I The influence of ouabain (0.4 jM) on contractile force and cellular Na and K concentrations was investigated in isolated left atria of the guinea-pig at rest and at different beat frequencies. Simultaneously the binding of ouabain to the tissue was determined. 2 Strict dependence of rates of onset of positive iontropic action and of binding of ouabain on beat frequency are limited to conditions where no alterations of cellular Na and K concentrations occur. A correlation was observed between sodium flux per unit time and the development of positive inotropism and binding to the receptors of ouabain. 3 Ouabain exerts its positive inotropic effect without affecting the intracellular Na and K concentrations in spite of the fact that under these conditions even the majority of binding sites, i.e. Na-Kadenosine triphosphatases (Na-K-ATPases), are occupied by the drug. The positive inotropic effect. may be explained by a ouabain-induced conformational alteration of the Na-K-ATPase which leads to structural alterations of the plasmalemma connected with an increased availability of coupling calcium. 4 Increasing the frequency of stimulation over a critical value, which appears to be determined by an overloading of the Na pump, induces a decrease in contractile force, cellular accumulation of Na and loss of K, and eventually contracture.

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Section: Discussionsupporting

confidence: 75%