Effect of mercurascan on the contractility and excitability of dog papillary muscle in vitro.

The authors studied in 6 experimental series the effect of Mercurascan (2-hydromercurifluorescein and 4-hydroxymercurifluorescein) on isolated dog papillary muscle in vitro; they evaluated the magnitude and character of its electrically stimulated contractions. It was found that at concentration of 10(-3)M and 10(-4) M, Mercurascan (MSC) exerts a significant positive inotropic effect on papillary muscle. Incubation of the muscle in a medium containing MSC at the above-given concentrations significantly suppressed the positive inotropic and arrhythmogenic effect of adrenalin, added in an over-threshold dose into the nutrient medium.