Positive inotropic action of dimethylamiloride in normal rat isolated hearts and papillary muscle and its primary mechanism / 中国药理学通报

Aim To study the inotropic action of DMA in normal rat isolated hearts and papillary muscle and search for its primary mechanism.Methods With Lansendorff-perfusion and isolated papillary muscle perfusion,cardiac performance and the systolic function of papillary muscle were measured to estimate the inotropic action of DMA;L-calcium channel blocker and sodium calcium exchanger(NCX)inhibitor were used to search for its primary mechanism.Results ①(1~20)?mol?L-1 DMA exerted a positive inotropic action in normal rat isolated hearts,that is in Langendorff-perfused hearts,DMA enhanced cardiac performance,i.e.LVSP-LVDP,+dp/dtmax,-dp/dtmax significantly(P