Effects of angiotensin Ⅱ and captopril on outward potassium channel currents in canine atrial myocytes / 中华急诊医学杂志

ABSTRACT

Objective To observe effects of angieminⅡ(AngⅡ)and captopril on outward potassium channel currents in canine atrial myoeytes,and to study mechanisnof Ang II and capupril on atrial arrhythmia.Method Ten healthy adult mongrel dogs(general class),weighing 15 to 20 kg,male and female informality,were provided bythe service centre of Tianjin Li-qun experimental animals.Single canine atrial myotcyte was acutely isolated and whole-cell configtmtion of the patch-clamp tchnique was used to detec trapidly activating delayed reefifier outward K+ current(Ikr),slowly activating delayed recti fier outward K+ current(Iks),ultra-rapidly aetivatin delayed rectifier outward K+ current(Ikur)and transient outward potassium current(Ito)before and after An II and captopril peffion.Software of pClamp 7.0 for windows and pClampfit 7.0 Was used to measure current and data were expressed as mean±standard deviation(x±s).SPSS 10.0 statistical was used for statistical analysis.The paired t test was useel for comparison betwn before and after treatment.P<0.05 was comidered as statistical significance.Results AngII(0.5/mol/L)increased Ikr and Iks,ilfibited Ito[(19.54±2.41)pA/pF vs.(24.83±2.52)pA/pF,P=0.001;(20.69±2.29)pA/pF Vfl.(25.59±3.42)pA/pF,P:0.0003;(6.34±1.93)pA/pF vs.(3.71±1.50)pA/pF,P=0.001)],and had no effect on k[(19.78±1.22 pA/pr Vs.(20.39±1.50)pA/pF,P=0.258)].Captopril(5tot/L)had no significant effect on Ikr.,b.k and[(19.11 4-4.91)pA/pF vs.(18.99 4-4.04)-∥pF,P=0.808;(20.76 4-2.89)pA/pF vs.(20.27 a-3.46)pA/pF,P=0.305;(18.50 4-3.78)pA/pF vs.(18.25 4-4.02)pA/pF,P=0.704;(7.31±1.99)pA/pF vs.(6.89±2.12)pA/pF,P=0.136)].Conclusioas AngⅡmay promote atrial electrical remocof atrial fibrillation through outward potassium currents.As angiotemin-eonverting enzy/ne inhibitor.captioruk can prevent atrial electrical rodding of atrial fibrillation by inhibiting renin-angiotensin-system.