Cardiotonic effects of proscillaridin A

Cardiotonic effect of proscillaridin A, cardiac glycoside derived from a squill, was tested in some methods. 1. Lethal doses (Hatcher doses) of proscillaridin A were 0.142mg/kg in cats, 0.152mg/kg in dogs, and 0.484mg/kg in rabbits, whereas the dose of g-strophanthin was 0.104mg/kg in cats. 2. 3.16×10-8 Molar concentration of proscillaridin A showed a persistent 60% increase of contractile force in cat papillary muscle preparation. 3. Contractile force of left ventricular muscle showed 9% increase after the second administration (total proscillaridin A 0.04mg/kg) in phenobarbital induced myocardial depression. 4. The ratio between the maximum rate of development isometric tension (dp/dt) and a constant fraction of the integrated isometric tension developed (IIT) showed 12% increase after the second administration of proscillaridin A.