[Effects of E 4031 on isolated cardiac function and resting Ca2+ level of myocardial cells from rats with chronic heart failure].

Objective: To investigate the effects of E 4031, a sodium calcium exchanger (NCX) agonist, on the isolated cardiac function and resting Ca2+ level in myocardial cells from rats with chronic heart failure.
Methods: Rats chronic heart failure model was established by abdominal aorta coarctation with; Isolated heart perfusion by Langendorff apparatus was used to detect heart function and the effects of E 4031 on haemodynamic indexes; Myocardial cells of rats in the model group were extracted quickly and co-incubated with calcium fluorescent indicator fluo3/AM and the impact of E 4031 on the fluorescence intensity in myocardial cells were evaluated by confocal microscopy.
Results: Heart function of rats in the model group detected by Langendorff perfusion was significantly reduced after 12 weeks, E 4031 at 10 micromol/L could improve their left ventricular developed pressure(LVDP) and systolic / diastolic maximum rate (+/- dp/dtmax). Compared with the control and sham operation groups, the resting Ca2+ fluorescence intensity of the myocardial cells of rats in model group was at a higher level and went through a process of transient rise and drop, then stably remaining at a low level after co-incubated with 10 micromol/L E 4031.
Conclusion: E 4031 can improve the isolated heart function of rats with chronic heart failure, which may be associated with its enhancing the activity of NCX in the myocardial cell membrane and stabilizing intracellular Ca2+ level.