Gerhard Szymanski

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Most considerations and models concerning myocardial dynamic properties e.g. potentiation and staircase, are based upon the existence of storage structures in the heart muscle cell. The phenomenon of biphasic tension development (or two-component contraction) in heart muscle preparations of several mammalian species suggests that the sarcoplasmic reticulum(More)
This paper records the results of an investigation into potentiation and staircase phenomena in rightventricular guinea-pig papillary muscles with particular reference to the sarcoplasmic Ca2+-channel. As a tool to isolate the second (‘late’, ‘1tonic’) component of isoproterenol-induced biphasic contractions ryanodine was used. On the evidence at present(More)
More than 100 years after Bowditch's discovery of the "Treppe" phenomenon the mechanism of the striking rate and rhythm dependence of cardiac contraction is not unequivocally established. Beside sophisticated techniques biphasic contractions seemed to be a promising approach. There was soon a general agreement that the first component of biphasic(More)
On the basis of a specialized two-Ca store model the degree of coupling q between the two stores was introduced. q is defined by the time constants of the model (leakage and coupling time constant) and varies between O (uncoupled stores) and 1 (maximal coupled stores). Provided that the contraction height in first approximation is proportional to the(More)
Concentrations of 1–4 μmol l−1 isoproterenol cause both in right ventricular papillary muscles and in enzymatically isolated myocytes of the guinea-pig a Ca2− overload-induced state which is functionally characterized by biphasic (multiphasic) twitches and biphasic (multiphasic) intracellular calcium transients, respectively, during excitation-contraction(More)
Potentiation phenomena, tetanization and staircase of isolated surviving ventricle strips excised from hearts of 16 frogs (Rana esculenta) were studied under quasiisometric conditions. Pseudopotentiation of all kind, biphasic staircases and superposition of contractions characterizing the hypodynamic state following excision disappear in-vitro not only(More)
Diastolic mechanical oscillations of right ventricular rabbit papillary muscles investigated at 15 degrees C in the perfusion chamber were analysed using a relaxation model with 6 parameters. From this analysis follows that the first diastolic oscillation amplitude plotted against the driving interval ("interval amplitude curve" of the first diastolic(More)
Myocardial diastolic tonus increases at low temperature. The chief aim of the present series of experiments was to decide whether this phenomenon should be interpreted as being caused by thermoelastic alteration or by an impairment of the Ca-pump. All experiments were performed on isolated right ventricular rabbit papillary muscles. In order to impose(More)