Regulation of AT1-Calcineurin signaling pathway on inward rectifier potassium ionic channel remolding of hypertrophic atrial myocytes from neonatal rats
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摘要: 目的:探讨血管紧张素Ⅱ受体1型(AT1)-钙调神经磷酸酶(CaN)信号通路对肥大乳鼠心房肌细胞内向整流钾电流(IK1)离子通道重构和动作电位时程(APD)改变的调控作用。方法:酶解法分离获得1d龄SD乳鼠心房肌细胞,据干预方式不同分为4组:对照组;牵张肥大组:牵张刺激24h;替米沙坦组:1μmol/L替米沙坦干预1h,牵张24h;环孢素(CsA)组:0.25μg/ml CsA干预1h,牵张24h。免疫印记法检测Kir2.1、CaN A亚基表达。全细胞膜片钳技术检测细胞膜IK1和单细胞APD的变化。结果:牵张刺激导致心房肌细胞肥大,促进CaN A亚基和Kir2.1蛋白表达,增大IK1电流密度,缩短动作电位复极50%(APD50)和复极90%(APD90);CsA和替米沙坦干预显著抑制牵张刺激的上述效应。结论:AT1-CaN信号通路参与调控肥大乳鼠心房肌细IK1离子通道重构和APD改变。Abstract: Objective:To investigate the role of angiotensin Ⅱ receptor 1type(AT1)-calcineurin(CaN)signaling pathway in inward rectifier potassium current(IK1)ionic channel remolding and action potential(AP)change of hypertrophic atrial myocytes from neonatal rats.Method:The atrial myocytes were isolated from 1-d-old SD rats and cultured on silicone sheeting for 24 h,and they were divided into 4groups depending on the treatment administered:Control,Stretch-induced hypertrophy(Stretched;cells were stretched for 24h),Telmisartan(cells were incubated with 1μmol/L Telmisartan for 1hthen stretched for 24h),and Cyclosporin-A(CsA;cells were incubated with 0.25μg/ml CsA for 1hthen stretched for 24h)groups.The proteins expression of kir2.1and CaN A subunit(CaNA)were assayed by western blot analysis.IK1 and AP were recorded by whole-cell patch clamp technique.Result:Stretch stimulation lead to atrial myocyte hypertrophy,promoted the expression of kir2.1and CaNA proteins,increased the density of IK1,and shorten the AP duration(APD)at 50% and 90%level of repolarization,which were significantly attenuated by incubation with Telmisartan and CsA.Conclusion:AT1-CaN signaling pathway plays an important role in regulating IK1 ionic channel remolding and AP change of stretch-induced hypertrophic atrial neonatal myocytes.
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Key words:
- atrial myocyte /
- potassium channel /
- action potential /
- remolding /
- whole-cell patch clamp technique
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