人心肌三磷酸腺苷敏感性钾通道的结构异质性及其与心房扩大的关联

Differential structure of ATP-sensitive potassium channels in human hearts and its association with atrial expanding

目的探讨人心房肌和心室肌细胞膜上三磷酸腺苷敏感性钾通道(KATP)的结构差异性,及其主要调节亚单位磺酰脲类受体(SUR1和SUR2A)两者mRNA表达量与心房扩大的关系。方法应用逆转录聚合酶链式反应分析正常个体心房肌和心室肌组织中KATP主要配基SUR1和SUR2A mRNA表达量的差异(共7例,左房/左室),对比正常个体左右心房(左房7例,右房6例)SUR1和SUR2A mRNA表达量的差异,并比较病人组扩大心房(8例)和正常心房(29例)两种配基的mRNA表达量差异。结果 KATP通道配基SUR1在正常个体心房中mRNA的表达高于心室(0.438 00±0.197 42 vs 0.219 7±0.077 11,P<0.05),SUR2A则在心室的表达明显高于心房(0.543 7±0.091 61 vs 0.331 9±0.087 35,P<0.05)。正常个体左房和右房中两种调节亚基其mRNA的表达量无差异,P>0.05。病人组扩大心房中SUR1表达明显增加(0.595 9±0.081 56 vs 0.331 8±0.051 08,P<0.05;心房扩大后SUR2A的表达量也有增加(0.556 1±0.175 76 vs 0.380 1±0.108 94,P<0.05)。结论正常人心房肌和心室肌细胞膜上的KATP通道存在结构异质性,心房肌的主要配基为SUR1,而心室肌主要是SUR2A,两种配基其mRNA的表达量随心房的扩大而改变。

Objective To investigate the difference of ATP-sensitive potassium channel （K_ATP ） composition between atria and ventricle in the human heart, and the possible relationship between the expression level of its main subunits sulfo- nylurea receptors（ SUR1 and SUR2A） and expansion of the atrium. Methods The mRNA expression of the KATe targets SUR1 and SUR2A in the left atria and ventricles of normal human （NF, n = 7 ） hearts were analyzed, and the level of mRNA was half quantified by revers transcription polymerase chain reaction, and the expression level of subunits （SUR1 and SUR2A） between left（ n = 7 ） and right（ n = 6 ） atria from NF was compared. Their expression level also were compared in expanding atrial （ n = 8 ） with normal atrial （ n = 29）. Result The expression level of SUR1 mRNA in atrium was grea- ter than that in ventricle（0.438 00 ±0. 197 42 vs 0. 219 7 ±0. 077 11 ,P 〈0.05）. The expression level of both SUR2A mRNA in ventricle was greater than that in atrium（0. 543 7 ±0.091 61 vs 0.331 9 ±0.087 35, P 〈0.05）. The expression level of both SUR1 mRNA and SUR2A mRNA increased obviously when the atrium was expanded（ SUR1 ：expanding 0.595 9 ±0. 081 56 vs normal 0.331 8 ± 0. 051 08 ,P 〈0.05 ;SUR2A：expanding 0. 556 1 ±0. 175 76 versus normal 0. 380 1 ± 0. 108 94, P 〈 0.05 ）. Conclusion KATP channels are heterogeneously expressed in the human heart, SUR1 is a domina- ting component of atrial, while SUR2A is essential for ventricle, and the expression level of SUR1 mRNA and SUR2A mR- NA increased with the expanding of the atrium.