Kuwahara M, Miyaji T, Tsubone H
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.
Eur J Pharmacol. 2000 Jan 24;388(1):21-7. doi: 10.1016/s0014-2999(99)00861-4.
We investigated the Ca(2+) signaling pathways of the response to angiotensin II in pleural mesothelial cells and the role of these Ca(2+) signaling pathways in mesothelial cell proliferation. Rat pleural mesothelial cells were maintained in vitro, and the Ca(2+) movement to angiotensin II was evaluated using the fluorescent Ca(2+) indicator fura 2. Furthermore, proliferation of mesothelial cells was assessed using a spectrophotometric 3-(4, 5-dimethylthazol-2-yl)-2,5-diphenyl-2H-tetrasodium bromide (MTT) assay. Angiotensin II (1 pM-100 microM) induced in mesothelial cells a biphasic elevation of intracellular Ca(2+) concentration (Ca(2+)) that consisted of a transient initial component, followed by a sustained component. Neither removal of extracellular Ca(2+) nor inhibition of Ca(2+) influx by 1 microM nifedipine affected the angiotensin II-induced initial transient elevation of Ca(2+) in mesothelial cells. Nifedipine did not block angiotensin II-induced sustained elevation of Ca(2+). Angiotensin II (1 pM-100 microM) had a proliferative effect on mesothelial cells in a dose-dependent manner. Angiotensin II type 1 (AT(1)) receptor antagonist ([Sar(1), Ile(8)]angiotensin II) inhibited both angiotensin II-induced elevation of Ca(2+) and proliferation of mesothelial cells. Pertussis toxin did not affect angiotensin II-induced responses. These results suggest that angiotensin II-induced responses to mesothelial cells are extremely dependent on the angiotensin AT(1) receptor coupled with pertussis toxin-insensitive G protein.
我们研究了胸膜间皮细胞中对血管紧张素II反应的Ca(2+)信号通路以及这些Ca(2+)信号通路在间皮细胞增殖中的作用。将大鼠胸膜间皮细胞进行体外培养，使用荧光Ca(2+)指示剂fura 2评估对血管紧张素II的Ca(2+)移动情况。此外，使用分光光度法3-(4,5-二甲基噻唑-2-基)-2,5-二苯基-2H-四氮唑溴化钠（MTT）检测法评估间皮细胞的增殖情况。血管紧张素II（1 pM - 100 microM）在间皮细胞中诱导细胞内Ca(2+)浓度（Ca(2+)）出现双相升高，包括一个短暂的初始成分，随后是一个持续成分。去除细胞外Ca(2+)或用1 microM硝苯地平抑制Ca(2+)内流均不影响血管紧张素II诱导的间皮细胞中Ca(2+)的初始短暂升高。硝苯地平不阻断血管紧张素II诱导的Ca(2+)持续升高。血管紧张素II（1 pM - 100 microM）对间皮细胞具有剂量依赖性的增殖作用。血管紧张素1型（AT(1)）受体拮抗剂（[Sar(1),Ile(8)]血管紧张素II）抑制血管紧张素II诱导的Ca(2+)升高以及间皮细胞的增殖。百日咳毒素不影响血管紧张素II诱导的反应。这些结果表明，血管紧张素II诱导的对间皮细胞的反应极依赖于与百日咳毒素不敏感的G蛋白偶联的血管紧张素AT(1)受体。
