Angiotensin II increases the cytosolic calcium activity in rat podocytes in culture
Angiotensin II increases the cytosolic calcium activity in rat podocytes in culture
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血管紧张素 II 可提高培养大鼠荚膜细胞的细胞膜钙活性
DOI：
10.1038/ki.1997.383
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发表时间：
1997-09-01
影响因子：
19.6
通讯作者：
Pavenstadt, H
中科院分区：
文献类型：
--
作者：
Henger, A;Huber, T;Pavenstadt, H
在肾小球中，血管紧张素II （angii）降低超滤系数，增强大分子的过滤。在肾小球损伤期间，血管紧张素转换酶抑制剂对肾素-血管紧张素系统的抑制可减少蛋白尿，并延缓进展为终末期肾功能不全。Ang II调节肾小球功能的机制仍在研究中。为了研究Ang II是否可以调节足细胞内的胞质钙活性（[Ca2+](i)），我们对这些细胞进行短期培养，并在单个足细胞中使用Fura-2微荧光技术检测Ang II的作用。体外培养足细胞特异性抗体WT-1和pp44的表达证实了培养足细胞的细胞特性。Ang II导致浓度依赖性，可逆和缓慢的[Ca2+]增加(i)， EC50为3 nmol/l Ang II （N = 229）。10 nmol/l Ang II使[Ca2+](i)从41 +/- 9增加到260 +/- 34 nmol/l （N = 210）。在细胞外Ca2+浓度降低为10 μ mol/l的溶液中，Ang ii介导的[Ca2+](i)增加显着减少了60 +/- 20% (N = 12)，表明[Ca2+](i)增加是由于Ca2+从细胞外空间内流入和Ca2+从细胞内储存释放所致。非选择性离子通道抑制剂氟芬酸酯显著抑制Ang ii介导的[Ca2+](i)升高（IC50 = 20 μ mol/l, N = 29），而l型Ca2+通道阻滞剂尼卡地平即使在高浓度>.1 μ mol/l时也只有很小的抑制作用。AT(1)受体拮抗剂氯沙坦抑制Ang ii介导的[Ca2+](i)增加，IC50约为0.3 nmol/l （N = 35）。数据表明，Ang II增加足细胞中的[Ca2+](i)是通过非选择性通道的Ca2+流入和细胞内储存的Ca2+释放。Ang II的作用是通过AT(1)受体介导的。
In the glomerulus, angiotensin II (Ang II) reduces the ultrafiltration coefficient and enhances the filtration of macromolecules. During glomerular injury, inhibition of the renin-angiotensin system by angiotensin-converting-enzyme inhibitors reduces proteinuria and retards the progression to end-stage renal insufficiency. The mechanisms by which Ang II modulates glomerular function are still a matter of investigation. To study whether Ang II may regulate the cytosolic calcium activity ([Ca2+](i)) in podocytes, these cells were propagated in short-term culture and the effect of Ang II was examined with the Fura-2 microfluorescence technique in single podocytes. The cellular identity of cultured podocytes was proven by the expression of WT-1 and pp44, specific antibodies against podocytes in vivo. Ang II led to a concentration-dependent, reversible and slow increase of [Ca2+](i) with an EC50 of 3 nmol/liter Ang II (N = 229). Ten nmol/liter Ang II increased [Ca2+](i) from 41 +/- 9 to 260 +/- 34 nmol/liter (N = 210). In a solution with an extracellular reduced Ca2+ concentration of 10 mu mol/liter, Ang II-mediated [Ca2+](i) increase was significantly reduced by 60 +/- 20% (N = 12), indicating that the [Ca2+](i) increase was due to a Ca2+ influx from the extracellular space and a release of Ca2+ from intracellular stores. Flufenamate, an inhibitor of non-selective ion channels, significantly inhibited Ang II-mediated increase of [Ca2+](i) (IC50 = 20 mu mol/liter, N = 29), whereas the L-type Ca2+ channel blocker nicardipine even in high concentrations of > 1 mu mol/liter had only a small inhibitory effect. The AT(1) receptor antagonist losartan inhibited Ang II-mediated [Ca2+](i) increase with an IC50 of about 0.3 nmol/liter (N = 35). The data suggest that Ang II increases [Ca2+](i) in podocytes by an influx of Ca2+ through non-selective channels and by a release of Ca2+ from intracellular stores. The effect of Ang II is mediated via an AT(1) receptor.