Na+/Ca2+ exchange current in myocytes isolated from rat hypertrophied heart

Effects of myocardial hypertrophy on the Na+/Ca2+ exchange current in isolated rat cardiac myocytes were investigated, using whole cell patch techniques. Goldblatt 2-kidney, one-clip technique was used to induce cardiomyocyte hypertrophy. The results demonstrated that the Ni(2+)-sensitive Na+/Ca2+ exchange current density was larger in hypertrophied cells than that in normal cells. At a holding potential of mV, the outward current densities were 1.53 +/- 0.31 pA/pF in normal cells and 2.62 +/- 0.53 pA/pF in hypertrophied cells (P < 0.01). At a holding potential of -100 mV, the inward current densities were 0.42 +/- 0.14 pA/pF in normal cells and 1.12 +/- 0.33 pA/pF in hypertrophied cells (P < 0.001). The results suggest that during myocardial hypertrophy the Na+/Ca2+ exchange current is significantly increased.