Upregulation of L-type Ca2+ channels in mesenteric and skeletal arteries of SHR
Upregulation of L-type Ca2+ channels in mesenteric and skeletal arteries of SHR
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DOI：
10.1161/01.hyp.0000025877.23309.36
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发表时间：
2002-08-01
期刊：
影响因子：
8.3
通讯作者：
Rusch, NJ
中科院分区：
文献类型：
--
作者：
Pratt, PF;Bonnet, S;Rusch, NJ
在自发性高血压大鼠（SHR）的肠系膜血管平滑肌细胞中，已证实二氢吡啶敏感的L型Ca2+通道的Ca2+内流增加。本研究探讨了L型Ca2+通道的成孔α(1C)亚基的上调是否是这种离子缺陷的基础。利用12 - 16周龄的SHR和正常血压的Wistar Kyoto（WKY）大鼠的肠系膜弓状动脉，逆转录聚合酶链反应显示，SHR动脉中对应于α(1C)亚基mRNA的扩增cDNA水平升高。蛋白质印迹证实，与WKY肠系膜动脉相比，SHR中α(1C)亚基蛋白的免疫反应信号增加了3.4倍，且mRNA表达增加与之相关，免疫细胞化学在单细胞水平证实了这种异常。最后，从SHR分离的肠系膜动脉对贝亚K8644高度敏感，并产生异常的Ca2+依赖性张力，表明α(1C)亚基上调在血管高反应性中具有功能性作用。为了确定这些Ca2+通道异常是否延伸到SHR骨骼肌床，我们在WKY和SHR后肢动脉中重复了一系列类似的研究。SHR的骨骼肌动脉也比WKY动脉表达更高水平的α(1C)亚基mRNA和蛋白，并产生归因于L型Ca2+通道的异常Ca2+依赖性张力。我们的数据首次提供了证据，表明α(1C)亚基mRNA和蛋白在SHR动脉中上调，并且L型Ca2+通道孔数量的增加与异常血管张力的产生有关。
An increased Ca2+ influx attributed to dihydropyridine-sensitive L-type Ca2+ channels has been demonstrated in mesenteric vascular smooth muscle cells of spontaneously hypertensive rats (SHR). This study examined whether an upregulation of the pore-forming alpha(1C) subunit of the L-type Ca2+ channel underlies this ionic defect. With the use of mesenteric arcade arteries from 12- to 16-week-old SHR and normotensive Wistar Kyoto (WKY) rats, reverse transcriptase-polymerase chain reaction demonstrated an increased level of amplified cDNA corresponding to the alpha(1C) subunit mRNA in the SHR arteries. Western blots confirmed that the increased mRNA expression was associated with a 3.4-fold increase in the immunoreactive signal of the alpha(1C) subunit protein in SHR compared with WKY mesenteric arteries, and immunocytochemistry confirmed this abnormality at the single-cell level. Finally, isolated mesenteric arteries from SHR were highly reactive to Bay K8644 and developed anomalous Ca2+-dependent tone, suggesting a functional role for alpha(1C) subunit upregulation in vascular hyperreactivity. To determine if these Ca2+ channel abnormalities extended to the SHR skeletal muscle bed, we repeated a similar series of studies in WKY and SHR hind limb arteries. Skeletal muscle arteries from SHR also expressed higher levels of alpha(1C) subunit mRNA and protein than WKY arteries and developed anomalous Ca2+-dependent tone attributed to L-type Ca2+ channels. Our data provide the first evidence that the alpha(1C) subunit mRNA and protein are upregulated in SHR arteries and that the increased numbers of L-type Ca2+ channel pores are associated with the generation of abnormal vascular tone.