Enhancement of receptor-operated cation current and TRPC6 expression in arterial smooth muscle cells of deoxycorticosterone acetate-salt hypertensive rats
Enhancement of receptor-operated cation current and TRPC6 expression in arterial smooth muscle cells of deoxycorticosterone acetate-salt hypertensive rats
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DOI：
10.1097/hjh.0b013e3280148312
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发表时间：
2007-04-01
影响因子：
4.9
通讯作者：
Ho, Won-Kyung
中科院分区：
文献类型：
--
作者：
Bae, Young Min;Kim, Aeran;Ho, Won-Kyung
在醋酸脱氧皮质酮（DOCA）盐高血压大鼠中，血管对血管活性激动剂的反应性改变通常与血压升高有关。典型瞬时受体电位（TRPC）通道被认为编码受体操作阳离子通道（ROC），其激活参与平滑肌去极化和血管收缩。本研究的目的是探讨doca高血压大鼠的ROC电流是否增加，并确定醛固酮是否直接提高TRPC的表达。方法采用制氨抑素穿孔膜片钳技术，对假手术和doca盐高血压大鼠经酶解后的肠系膜动脉平滑肌细胞进行受体刺激离子电流记录。采用逆转录聚合酶链反应（RT-PCR）和Western blot检测TRPCs的表达。结果与假手术大鼠相比，doca盐高血压大鼠肠系膜动脉平滑肌细胞中5-羟色胺和去甲肾上腺素激活的受体刺激电流明显增加。离子取代实验表明，增强电流为阳离子电流（ROC电流）。实时RT-PCR证实了doca盐高血压大鼠肠系膜动脉中TRPC6的表达增强。RT-PCR和western blot也观察到醛固酮在体外处理A7r5细胞中TRPC6的上调。结论醛固酮增强血管平滑肌细胞TRPC6的表达和ROC电流，这可能导致血管反应性改变和高血压。
Objectives In deoxycorticosterone acetate (DOCA)-salt hypertensive rats, altered reactivity of blood vessels to vasoactive agonists is frequently associated with an elevation in blood pressure. Canonical transient receptor potential ( TRPC) channels are believed to encode receptor-operated cation channels (ROC), the activation of which is involved in smooth muscle depolarization and vasoconstriction. The aims of the present study were to investigate whether the ROC current is increased in DOCA-hypertensive rats and determine whether aldosterone directly enhances the expression of TRPC.Methods The nystatin-perforated patch-clamp technique was used for the recording of receptor-stimulated ion currents in mesenteric arterial smooth muscle cells, which were enzymatically dispersed from sham-operated and DOCA-salt hypertensive rats. Expressions of TRPCs were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and by Western blot analysis.Results Receptor-stimulated currents activated by 5-hydroxytryptamine ( serotonin) and norepinephrine were increased significantly in the mesenteric arterial smooth muscle cells of DOCA-salt hypertensive rats compared to sham-operated rats. Ion-substitution experiments revealed that the enhanced currents were cation currents (ROC currents). Enhanced expression of TRPC6 in mesenteric arteries from DOCA-salt hypertensive rats was demonstrated by real-time RT-PCR. Up-regulation of TRPC6 by aldosterone treatment in vitro was also observed in A7r5 cells by RT-PCR and in western blots.Conclusion These results suggest that aldosterone enhances TRPC6 expression and ROC currents in vascular smooth muscle cells, and that this may in turn contribute to altered vascular reactivity and to hypertension.