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Enhancement of Ca~(2+) transients and contraction of single ventricular myocytes of rats by 5-(N, N-dimethyl) amiloride

Cui Xiangli, Chen Huanzhen, Wu Dongmei, Wu Bowei

Department of Physiology,Shanxi Medical University.Taiyuan 030001,Shanxi

Abstract

The results showed that 10 #mu#mol/L DMA increased Ca~(2+) transient and cell shortening from 209.60±54.96 and 3.07±0.97 #mu#m to 238.50±80.41 and 4.07±1.02 #mu#m, respectively (P<0.05), which was completely abolished by application of KB-R7943, a specific reverse mode Na~(+)/Ca~(2+) exchanger blocker. After blocking L-type Ca~(2+) channels by nicardipine, DMA also enhanced Ca~(2+) transient and cell shortening. In rats with myocardial hypertrophy, DMA showed the common pharmacologic profile as in normal rats but more intense stimulating effects on Ca~(2+) transient and cell contraction. The results suggest that DMA increase Ca~(2+) transient and cell contraction via stimulating reverse mode Na~(+)/Ca~(2+) exchange, and the stimulating effect is more pronounced in rats with myocardial hypertrophy than in normal ones.

Key words: Fura-2;Calcium;Contraction;Sodium-calcium exchanger;Myocardium;Hypertrophy ;

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Citing This Article：

Cui Xiangli, Chen Huanzhen, Wu Dongmei, Wu Bowei. Enhancement of Ca~(2+) transients and contraction of single ventricular myocytes of rats by 5-(N, N-dimethyl) amiloride. Acta Physiol Sin 2002; 54 (3): (in Chinese with English abstract).