Antisympathomimetic Effects of Kö 1313 and Kö 1366 in Guinea-Pig Atria

Antisympathomimetic effects of Kö 1313 and Kö 1366 in guinea-pig atria.

The antagonistic effects of two new ƒÀ-receptors blocking agents, Ko 1313 and Ko 1366 against the chronotropic and inotropic responses to noradrenaline and tyramine were studied on the isolated right and left atria of guinea-pigs. From the KB values estimated by means of three different methods, it was found that the potencies of KO 1366 were 5 to 10 times and 5 to 7 times those of Ko 1313 in t...

Clinical pharmacological studies of Kö 1173--a new antiarrhythmic agent.

Effect of Sodium Valproate on Ouabain-Induced Arrhythmia in Isolated Guinea-Pig Atria

Sodium valproate (SV), an antiepileptic drug has several mechanism of action. It inhibits voltage sensitive Na+ channels and reduces intracellular Na accumulation. These actions are similar to that of both phenytoin and carbamazepine. We have investigated the direct cardiac action of SV and its effects on ouabain-induced arrhythmia in isolated guinea-pig atria. The guinea-pig atrium was dissect...

Calcium Flux and Contractility in Guinea Pig Atria

The calcium in guinea pig atria can be divided into three components by kinetic studies with Ca(45): (a) a rapidly exchangeable fraction with a half-time of 4.5 minutes; (b) a slowly exchangeable fraction with a half-time of 86 (or 168) minutes; and (c) an inexchangeable fraction. In Krebs-Henseleit solution containing 2.5 mM calcium, the calcium content of the tissue at rest remains constant, ...

Possible Relaxant Effects of Thymoquinone on Guinea Pig Tracheal Chain

In the previous studies the relaxant, anti-cholinergic (functional antagonism) and anti-histaminic effects of Nigella sativa have been demonstrated on guinea pig tracheal chains. To elucidate the main substance responsible for the relaxant effect of this plant, the effect of thymoquinone, one of the main constituent of Nigella sativa was examined in this study. The bronchodilatory effects of th...