Koyama T, Oike M, Komiyama S, Ito Y
Department of Pharmacology, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan.
Am J Physiol. 1999 Dec;277(6):L1089-95. doi: 10.1152/ajplung.1999.277.6.L1089.
We examined the effects of superoxide anion (O(-2)) on the intracellular Ca(2+) concentration in cultured human nasal epithelial cells. The cells were exposed to O(-2) by pretreatment with xanthine (X) and xanthine oxidase (XO); control cells were treated with X alone. When Ca(2+)-containing Krebs solution was reperfused in the thapsigargin-treated, store-depleted cells, reapplication-induced intracellular Ca(2+) concentration elevation was significantly smaller in X/XO-treated cells than in the control cells, suggesting that O(-2) impairs Ca(2+) release-activated Ca(2+) entry (CRAC). Bath application of ATP induced a steep Ca(2+) transient in both control and X/XO-treated cells. However, the concentration-response curve of the ATP-induced Ca(2+) transient was shifted to a higher concentration in X/XO-treated cells. The impairments of CRAC and ATP-induced Ca(2+) transient induced by X/XO were reversed by superoxide dismutase. Furthermore, all these X/XO-induced effects were also observed in cells pretreated with pyrogallol, also an O(-2) donor. These results indicate that O(-2) impairs at least two mechanisms involved in Ca(2+) mobilization in human nasal epithelial cells, i.e., CRAC and ATP-induced Ca(2+) release.
我们研究了超氧阴离子（O(-2)）对培养的人鼻上皮细胞内钙离子浓度的影响。通过用黄嘌呤（X）和黄嘌呤氧化酶（XO）预处理使细胞暴露于O(-2)；对照细胞仅用X处理。当在经毒胡萝卜素处理、储存耗尽的细胞中重新灌注含Ca(2+)的Krebs溶液时，重新施加诱导的细胞内Ca(2+)浓度升高在X/XO处理的细胞中比在对照细胞中显著更小，这表明O(-2)损害了Ca(2+)释放激活的Ca(2+)内流（CRAC）。浴加ATP在对照细胞和X/XO处理的细胞中均诱导了陡峭的Ca(2+)瞬变。然而，在X/XO处理的细胞中，ATP诱导的Ca(2+)瞬变的浓度-反应曲线向更高浓度偏移。超氧化物歧化酶可逆转X/XO诱导的CRAC损害和ATP诱导的Ca(2+)瞬变。此外，在用邻苯三酚（也是一种O(-2)供体）预处理的细胞中也观察到了所有这些X/XO诱导的效应。这些结果表明，O(-2)损害了人鼻上皮细胞中至少两种参与Ca(2+)动员的机制，即CRAC和ATP诱导的Ca(2+)释放。
