Objective: To investigate the effects of 17-methoxyl-7-hydroxy-benzfuranchalcon (YLSC)on intracellular calcium overload in cultured cardiac myocytes of neonatal rats injured by H2O2and L-type calcium current(ICa-L) in isolated ventricular myocytes. Method: The cells of primary cultured cardiac myocytes of neonatal rats were divided into groups:①control group;② model group:administrated with 0.3 mmol·L-1 H2O2;③YLSC treated groups:incubation respectively with 100

200

400 μmol·L-1YLSC for 24 h

and add 0.3 mmol·L-1 H2O2.Laser confocal microscopy was used with Fluo-3/Am as indicator to detect changes of [Ca2+]i immediately and 15 mintues after H2O2 intervention. Single ventricular cell was obtained enzymatically by Langendorff perfusion apparatus. The wholecell patch clamp was used to record the ICa-L. Result: ①The average fluorescence intensity values of the model group treated by H2O2 higher significantly than control group and the fluorescence enhancement ratio was 60.43%±7.75%. The YLSC could decline the intensity values in a does-dependent manner manner

the fluorescence enhancement ratios of low

middle and high does respectively were 38.39%±13.87%

14.49%±2.94%

-28.1%±1.52%

and all of them were much lower compared with H2O2 group(P<0.01). ②YLSC can up-shifted the current-voltage(I-V) curves and markedly shifted the steady state activation and inactivation curve of ICa-L to the left. Conclusion: YLSC inhibited the L-type calcium channel

it can significantly reduce the myocardial intracellular Ca2+ overload induced by H2O2.