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The potency of neuropeptide Y (NPY) to cause negative and positive contractile responses in rat ventricular cardiomyocytes was investigated. In these cells, NPY was found to activate the transient outward K+ current (Ito) and the slow inward Ca2+ current (Isi). As reported before (H. M. Piper, B. C. Millar, and J. R. McDermott, Naunyn Schmiedeberg's Arch.(More)
This study describes electrophysiological effects of estrogens in isolated male rat ventricular myocytes. According to the literature these cells do not express the nuclear estrogen receptor. Action potentials or membrane currents were recorded in the whole-cell configuration with standard techniques. Action potential durations (APD) measured at a level of(More)
Tedisamil has been described as a selective inhibitor of a fast inactivating transient outward current (i(to,f)) in rat ventricular myocytes. Because recent reports demonstrated the existence of a second slowly inactivating transient component (i(to,s)) we investigated i(to,s) and differentiated the effects of tedisamil on both transient outward current(More)
  • U Borchard
  • 1990
A great number of beta-adrenoceptor blocking drugs are now available for clinical use which show great differences with respect to their pharmacokinetic properties. Bioavailability might be low because of a low absorption rate after oral application in the case of hydrophilic drugs like atenolol or might be low because of a high first-pass effect in the(More)
A great number of antiarrhythmic drugs is available for the treatment of tachyarrhythmias. The classification of these drugs according to their action on different ionic channels of cardiac cells is discussed and summarized. Furthermore, drugs are characterized with respect to their mechanism of action on membrane currents and their action in different(More)
1. Sotalol (Sotalex) and both its optical isomers were studied in electrophysiological experiments with respect to their class III activity of antiarrhythmic drugs. The three substances prolonged action potentials (AP) of guinea-pig papillary muscle and left atrium in concentrations greater than or equal to 3 mumol/l, whereas other AP parameters (resting(More)
(1) Effects of bepridil (0.3-100 mumol/l) on transmembrane currents which are active during the repolarization of the cardiac action potential were studied in sheep cardiac Purkinje fibres with the two-microelectrode voltage-clamp technique. Transmembrane currents were activated at a frequency of 0.03 Hz. (2) The initial inwardly rectifying current (iK1)(More)
Reestablishment of blood supply to ischemic myocardium leads to biochemical and cellular changes which are believed to reduce the amount of potentially salvageable myocardium (reperfusion injury). In this situation, adenosine is known to have myocardial protective properties. Activation of adenosine A2-receptors may account for most of the beneficial(More)
This study was aimed to differentiate the action of (+)- and (+/-)-sotalol (10-1000 mumol/l) on membrane currents which are active during the repolarization of cardiac action potentials. Effects where studied in shortened sheep cardiac Purkinje fibres with the two-microelectrode voltage-clamp technique. Action potentials were activated at a frequency of(More)
Intravenous magnesium lowers mortality in patients with suspected myocardial infarction. We tested the hypothesis that the protective effect may be due to a direct, local influence of magnesium on myocardial reperfusion injury in a dog model of ischaemia/reperfusion. Ten anaesthetized open chest dogs underwent 1 h of left anterior descending artery (LAD)(More)