摘要
Objective To investigate the long-term effects of imidapril (IMI) on action potential and calcium and potassium currents in rabbit left ventricular hypertrophic myocytes. Methods Rabbits were randomly divided into three groups: IMI-treated, hypertrophic and sham-operated control groups. Cardiac hypertrophy was induced in hypertrophy group by partial ligation of the abdominal aorta. In the IMI-treated group, the rabbits were administered IMI (1.5 mg·kg -1·d -1) for 8 weeks after surgery. In the sham-operated control group, the animals underwent an abdominal laparotomy without further procedure. Whole-cell patch clamp technique was used to record ionic currents. Results Membrane capacitance was larger in hypertrophic cells than in sham-operated cells or IMI-treated cells. Action potential duration was lengthened in hypertrophic cells and was remarkably shortened by IMI. The density of I Ca,L was reduced from 12.8±0.7 pA/pF in the sham-operated cells, to 7.7±0.8 pA/pF in hypertrophic cells, while it resembled the control cells after IMI treatment (11.9±1.0 pA/pF). After IMI treatment, the density of I Ks,tail was enhanced from 2.5±0.1 pA/pF in hypertrophic cells to 4.7±0.6 pA/pF (n=7, P<0.01), which was similar to the sham-operated cells. The densities of I to and I K1 were significantly increased in IMI-treated cells, from 3.8±0.4 pA/pF and 3.7±0.5 pA/pF in the hypertrophic cells to 6.4±0.8 pA/pF and 6.5±0.3 pA/pF, respectively, but the I Kr densities were not different in the three groups. Conclusion IMI could reverse the increase in membrane capacitance in hypertrophic cells, shorten action potential duration, and increase the densities of I Ca, L, I Ks, I to and I K1 in hypertrophic cells.
Objective To investigate the long-term effects of imidapril (IMI) on action potential and calcium and potassium currents in rabbit left ventricular hypertrophic myocytes. Methods Rabbits were randomly divided into three groups: IMI-treated, hypertrophic and sham-operated control groups. Cardiac hypertrophy was induced in hypertrophy group by partial ligation of the abdominal aorta. In the IMI-treated group, the rabbits were administered IMI (1.5 mg·kg -1·d -1) for 8 weeks after surgery. In the sham-operated control group, the animals underwent an abdominal laparotomy without further procedure. Whole-cell patch clamp technique was used to record ionic currents. Results Membrane capacitance was larger in hypertrophic cells than in sham-operated cells or IMI-treated cells. Action potential duration was lengthened in hypertrophic cells and was remarkably shortened by IMI. The density of I Ca,L was reduced from 12.8±0.7 pA/pF in the sham-operated cells, to 7.7±0.8 pA/pF in hypertrophic cells, while it resembled the control cells after IMI treatment (11.9±1.0 pA/pF). After IMI treatment, the density of I Ks,tail was enhanced from 2.5±0.1 pA/pF in hypertrophic cells to 4.7±0.6 pA/pF (n=7, P<0.01), which was similar to the sham-operated cells. The densities of I to and I K1 were significantly increased in IMI-treated cells, from 3.8±0.4 pA/pF and 3.7±0.5 pA/pF in the hypertrophic cells to 6.4±0.8 pA/pF and 6.5±0.3 pA/pF, respectively, but the I Kr densities were not different in the three groups. Conclusion IMI could reverse the increase in membrane capacitance in hypertrophic cells, shorten action potential duration, and increase the densities of I Ca, L, I Ks, I to and I K1 in hypertrophic cells.
