The membrane active antibiotics effects on rat heart myocardium

The effect of some membrane active ionophoric antibiotics on the amplitude of contractions of isolated rat heart right ventricle was studied. The effects of polyether nigericin, polyene amphotericin B and peptide antibiotic polymyxin B were examined. Nigericin in a concentration of 1.38 mu mol/L exerts a positive inotropic effect with its maximal value (+29%) 15 minutes after application. Amphotericin B in a concentration of 1.08 mu mol/L caused a positive inotropic effect, which was maximal in the 30(th) minute of the experiment (+28%). Polymyxin B in a concentration of 0.84 mu mol/L caused a positive inotropic effect, which was maximal (+32%) 20 minutes after application.