快速起搏大鼠心房肌细胞L-型钙通道及钾通道Kv4·3的表达变化

Expressions of L-type calcium channel and potassium channel Kv4.3 in rapid paced primary cultured atrial myocytes

目的利用原代培养的心房肌细胞建立快速起搏模型,研究L-型钙通道及钾通道Kv4·3在快速起搏早期的表达变化。方法原代培养大鼠心房肌细胞,并建立快速起搏细胞模型,利用RT-PCR以及Western-blot方法检测L-型钙通道α1c及钾通道Kv4·3在快速起搏3、6、12、24h后mRNA和蛋白的表达变化。结果快速起搏6h后L-型钙通道α1c的mRNA和蛋白表达较起搏前持续降低,并于24h时达到最低值;而钾通道Kv4·3mRNA和蛋白的表达在快速起搏12h后降低,并且在其后保持相对稳定的水平。结论快速起搏早期,原代培养心房肌细胞L-型钙通道α1c及钾通道Kv4·3的mRNA和蛋白表达均出现不同程度的降低,提示其发生了离子通道重构,并且可能是电重构的分子基础。

Objective To study the expressions of L-type calcium channel otlc and potassium channel Kv4.3 at early stages of atrial fibrillation in a rapid paced primary cultured atrial myocyte model. Methods Primary rat atrial myocytcs were cultured and a rapid paced cell model was established. The atrial cells were divided into five groups with pacing durations within 0 and 24 h. Reverse transcriptionpolymerase chain reaction and Western blot were applied to detect the messenger ribonucleic acid （mRNA） and proteins of L-type calcium channel α1 c and potassium channel Kv4.3, respectively. Results mRNA expression of L-type calcium channel α1c reduced after 6 h of rapid pacing and continued to decline as the pacing process. The decrease of L-type calcium channel α1 c protein was paralleled with mRNA expression and reached the lowest levels at 24 h. Similarly, changes of potassium channel Kv4.3 protein and mRNA were paralleled. Kv4.3 mRNA was not altered within the first 6 h. It was reduced after 12 h. However, longer pacing periods did not further decrease mRNA and protein expression levels of potassium channel Kv4.3. Conclusions Expressions of L-type calcium channel α1c and potassium channel Kv4.3 were both reduced at different levels in early phase of rapid pacing atrial myocytes. It implicates the occurrence of ion channel remodeling of atrial myocytes, which may serve as molecular mechanism of electrical remodeling in the development of atrial fihrillation.