钾离子通道亚单位mRNA在犬左右心室中层心肌中的表达

Comparison of expression of lon-channel subunit mRNA in midmyocardium of canine right ventricular with left ventricular.

目的研究犬左右室中层心肌短暂外向钾电流(Ito)、延迟整流钾电流缓慢激活成分(Iks)亚单位mRNA的表达情况,探讨左右室复极异质性的可能分子机制。方法应用逆转录-聚合酶链反应(RT-PCR)半定量分析犬左右室中层心肌Ito的α亚单位(Kv4.3)、β亚单位(KchIP2)、Iks的α亚单位(KvLQT1)mRNA的表达量(以β-actin为内参照)。结果Kv4.3 mRNA水平在左右室中层心肌中表达没有显著性差异(P>0.05),KchIP2 mRNA、Kv-LQT1 mRNA水平在右室中层心肌表达明显高于左室中层心肌(P<0.01或<0.05)。结论KchIP2、KvLQT1 mRNA水平在左右室中层心肌中表达上的差异可能是其离子流差异的分子基础。

Objective To investigate the inhomogeneity in distribution of ion channels subunit mRNA in midmyocardium of canine right ventricular（RV） versus left ventricular（LV） and the potential molecular mechanism of electrical nonuniformity in the RV versus the LV. Methods The mRNA expression and distribution of the transient outward current α-subunits Kv4.3, the β-subunit KchIP2 and the slow delayed-rectifier α-subunits KvLQT1 mRNA were quantified by semiquantitative reverse transcription-polymerase chain reaction （RT-PCR） in tissue sections obtained from different regions of canine myocytes including RV and LV midmyocardium. Results Kv4.3 potassium channel α-subunit mRNA expressed at equal levels in RV and LV midmyocardium（ P 〉 0.05 ） , but KchIP2 mRNA expressed much more strongly in RV midmyocardium than in LV midmyocardium （P〈0.01）. KvLQT1 mRNA was more abundant in RV midmyocardium than in LV midmyocardium （P〈0.05）. Conclusions The inhomogeneity in distribution of ion channels subunit mRNA in canine RV and LV midmyoeardium may serve as the molecular basis of regional variation in midmyocardial ionic currents.