Title: Positive inotropic action of dimethylamiloride in normal rat isolated hearts and papillary muscle and its primary mechanism
Abstract: 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)μmol·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(P0.05 or P0.01);in isolated papillary muscle,DMA improved TC(developed tension of contraction)and shortened T-dp/dtmax significantly(P0.05 or P0.01).② The positive inotropic action of DMA in normal rat isolated hearts could not be blocked by nicardipine(one of L-calcium channel blockers).③ The positive inotropic action of DMA in normal rat isolated hearts could be inhibited by NiCl2(one of sodium calcium exchanger inhibitors).Conclusion(1~20)μmol·L-1 DMA exerts positive inotropic action in normal rat isolated hearts.By agitating NCX,instead of L-calcium channel,DMA enhances cardiac performance and the systolic function of papillary muscle.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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