Effect of hydrogen peroxide on persistent sodium current in guinea pig ventricular myocytes  

作　　者：Ji-huaMA An-taoLUO Pei-huaZHANG 

机构地区：[1]Cardio-ElectrophysiologicalResearchLaboratory,MedicalCollege,WuhanUniversityofScienceandTechnology,Wuhan430080,China

出　　处：《Acta Pharmacologica Sinica》2005年第7期828-834,共7页中国药理学报（英文版）

基　　金：the Natural Science Foundation of Hubei Province(No 2003ABA189).

摘　　要：Aim:To study the effect of hydrogen peroxide(H202)on persistent sodium cur- rent(1_(Na.p))in guinea pig ventricular myocytes.Methods:The whole-cell,cell- attached,and inside-out patch-clamp techniques were applied on isolated ven- tricular myocytes from guinea pig.Results:H_2O_2(0.1 mmol/L,0.5 mmol/L and 1.0 mmol/L)increased the amplitude of whole-cell I_(Na.p)in a concentration-dependent manner,and glutathione(GSH 1 mmol/L)reversed the increased I_(Na.p).H_2O_2(1 mmol/L)increased persistent sodium channel activity in cell-attached and inside- out patches.The mean open probability was increased from control values of 0.015±0.004 and 0.012±0.003 to 0.106±0.011 and 0.136e0.010,respectively(P< 0.01 vs control).They were then decreased to 0.039±0.024 and 0.027±0.006, respectively,after the addition of 1 mmol/L GSH(P<0.01 vs H_2O_2).The time when open probability began to increase and reached a maximum was shorter in inside- out patches than that in cell-attached patches(4.8e 1.0 min vs 11.5+3.9 min,P<0.01; 9.6±1.6 min vs 18.7±4.7 min,P<0.01).Conclusion:H_2O_2 increased the I_(Na.P)of guinea pig ventricular myocytes in a concentration-dependent manner,possibly by directly oxidating the cell membrane.Aim:To study the effect of hydrogen peroxide(H202)on persistent sodium cur- rent(1_(Na.p))in guinea pig ventricular myocytes.Methods:The whole-cell,cell- attached,and inside-out patch-clamp techniques were applied on isolated ven- tricular myocytes from guinea pig.Results:H_2O_2(0.1 mmol/L,0.5 mmol/L and 1.0 mmol/L)increased the amplitude of whole-cell I_(Na.p)in a concentration-dependent manner,and glutathione(GSH 1 mmol/L)reversed the increased I_(Na.p).H_2O_2(1 mmol/L)increased persistent sodium channel activity in cell-attached and inside- out patches.The mean open probability was increased from control values of 0.015±0.004 and 0.012±0.003 to 0.106±0.011 and 0.136e0.010,respectively(P< 0.01 vs control).They were then decreased to 0.039±0.024 and 0.027±0.006, respectively,after the addition of 1 mmol/L GSH(P<0.01 vs H_2O_2).The time when open probability began to increase and reached a maximum was shorter in inside- out patches than that in cell-attached patches(4.8e 1.0 min vs 11.5+3.9 min,P<0.01; 9.6±1.6 min vs 18.7±4.7 min,P<0.01).Conclusion:H_2O_2 increased the I_(Na.P)of guinea pig ventricular myocytes in a concentration-dependent manner,possibly by directly oxidating the cell membrane.

关 键 词：hydrogen peroxide MYOCARDIUM patch clamp techniques sodium channels 

分 类 号：R542.2[医药卫生—心血管疾病]