P. Heistracher

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1. Contractile responses in short twitch-type snake muscle fibres have been studied. These fibres are sufficiently short to allow fairly uniform changes in membrane potential along their length when current is passed through an intracellular micropipette. Active sodium permeability changes were blocked with tetrodotoxin (TTX), procaine, or by using(More)
1. Contractile repriming has been studied in voltage-clamped snake twitch muscle fibres. Maintained depolarization causes a contractile response which inactivates after a few seconds. Repolarization of the fibre can restore its ability to contract to a subsequent depolarization. This restoration, or repriming, depends on the magnitude and the duration of(More)
54. Vincenzi, F. F., West, T. C. : Release of automatic mediators in cardiac tissue by direct subthreshold electrical stimulation. J . Pharmacol. exp. Ther. 141, 185 (1963). 55. Wallon, G., Corabceuf, E., Gargouil, Y. M. : Action de la v~ratrine sur l 'activit~ 41eetrique et m6canique du eceur. C. R. Soc. Biol. (Paris) (cir. 14). 56. Weidmann, S. : The(More)
The recently synthesized benzofuranylethanolamines GE 68, GE 70, GE 76, RG 16 and RG 25, were studied in guinea-pig isolated papillary muscles and right atria. With regard to their inotropic, chronotropic and beta-adrenoceptor-blocking activity, these compounds were compared with the reference drug propafenone. GE 68, GE 70 and GE 76 were almost equally(More)
Antidepressants and neuroleptic drugs are sometimes the reason for the occurrence of the polymorphic ventricular arrhythmia torsades de pointes in patients. Therefore, it was of interest to study the actions of some of these drugs such as imipramine, amitriptyline, doxepin, chlorpromazine, trifluoperazine and thioridazine in isolated, spontaneously beating(More)
1. The effect of procaine on the contractile responses of voltage clamped snake twitch muscle fibres has been investigated. Procaine hydrochloride shortened the duration of contractures produced by long depolarizing pulses. It also reduced the amount of inactivating outward current.2. The rate of repriming was greatly slowed by procaine. At -80 mV, for(More)
An improved synthesis of the enantiomers of the new benzofurane-type antiarrhythmic compound 1 is described, which makes use of the enantiomerically pure mbe-lactol. Thus, acylation of the benzofurane 4 with acetic anhydride and subsequent bromination gave the bromoacetyl-derivative 6, which, after reduction with LiAlH4, was protected with mbe-lactol to(More)
GE 68 ((Rac.)-1-[3-(Phenylethyl)-2-benzofuryl]-2-(propylamino)-ethanol hydrochloride) is structurally related to propafenone, and exerts negative inotropic and negative chronotropic effects similar to the parent drug, but lacks any β-adrenoceptor blocking activity contrary to propafenone. Thus, the electrophysiological effects of GE 68 were studied in(More)
1. The cardiotoxic effects of emetine dihydrochloride on mechanical and electrical activity were studied in isolated preparations (papillary muscles, sinoatrial and atrioventricular nodes, ventricular myocytes) of the guinea-pig heart. 2. Force of contraction was measured isometrically, action potentials and maximum rate of rise of the action potential were(More)