中文摘要：

目的：研究胡椒碱对H2O2引起的兔单个心房肌细胞内向整流钾电流（IK1）及超速激活的延迟整流钾电流（IKUr）异常的影响.方法：采用全细胞膜片钳技术分析50 μmol/L H2O2对兔单个心房肌细胞IK1和IKUr的影响,并研究预先应用7 μmol/L胡椒碱对其的保护作用.结果：7 μmol/L胡椒碱对正常兔心房肌细胞IK1和IKUr及其通道动力学无显著影响.在50 μmol/L H2O2作用下,兔心房肌细胞IK1峰值由（-148.2±16.7）pA/pF降低至（-64.2±9.8）pA/pF （P〈0.05）,电流-电压曲线上移;而IKUr峰值由（16.0±2.1）pA/pF降低至（6.1±1.4）pA/pF （P〈0.05）,电流-电压曲线下移,通道稳态激活曲线右移,通道稳态失活曲线左移及恢复时间减慢,而且存在频率依赖性特征.预先给予7 μmol/L胡椒碱,明显减轻H2O2对IK1和IKUr的抑制作用（P〈0.01）,并可减少H2O2对超速激活延迟整流钾通道动力学的异常影响.结论：胡椒碱可减轻氧化应激对心房肌细胞IK1和IKUr的影响.

英文摘要：

AIM： To study the protective effect of piperine on abnormalityies of inward rectifier potassium cur- rent （ IKl ） and ultra rapid delayed rectifier potassium current （ IKur） induced by hydrogen peroxide （ H2O2 ） in single rabbit atrial myocytes. METHODS： The technique of whole - cell patch - clamp was used to study the effect of H202 at concen- tration of 50 μmol/L on IK1 and IKur in single rabbit atrial myocytes. The protective effect of pretreatment with piperine （7 μmol/L） was also observed. RESULTS： The piperine at concentration of 7 μmol/L had no significant effect on Ik1 and IKUr and their channel dynamics. In the presence of H2 02 at concentration of 50 μmol/L, the peak currents of IKI and IKur reduced significantly （ P 〈 0. 05 ）. The steady - state activation curve of/gut Was shifted right, the steady - state inactivation curve of Igur was shifted left, and the recovery from inactivation of IKur was shifted downward. The IKUr showed frequency - dependent characteristics. Piperine at concentration of 7 μmol/L significantly alleviated the inhibitory effect of H2O2 on Ik1 and Igor（P〈0.01 ）. In addition, piperine protected against the changes of IKUr dynanlics induced by H2O2. CONCLUSION： Piperine alleviates the abnormalities of IK1 and IKur induced by oxidative stress in atrial myoeytes.