Effect of N-(4-butoxybenzyl) hyoscyaminium bromide (butropium bromide) on the isolated, blood-perfused canine atrium preparation.
The effects of butropium on chronotropic and inotropic activity were investigated in 10 isolated atrial preparations which were suspended in a bath and perfused with arterial blood led from a carotid artery of heparinized support dog. Butropium injected into the cannulated sinus node artery in a dose range of 3 to 100 microgram produced a dose-dependent positive chronotropic and inotropic effect. At relatively higher doses above 30 microgram, slight and brief initial negative chronotropic and inotropic effect followed by a long-lasting positive effect was observed. The positive effect of butropium was markedly suppressed by propranolol or carteolol, but it was not affected by tetrodotoxin or desmethylimipramine. From these results, a large amount of butropium may induce positive chronotropic and inotropic effect through cholinergic blockade and in part stimulation of adrenergic beta-receptors.
D000818:Animals; D001286:Atropine Derivatives / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology; D004285:Dogs; D005260:Female; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010477:Perfusion; D011433:Propranolol / Q000494:pharmacology; D013268:Stimulation, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology
D001286:Atropine Derivatives; D013779:Tetrodotoxin; D011433:Propranolol; C006846:butoxybenzyl hyoscyamine; D003891:Desipramine