Release of ATP from avian Muller glia cells in culture
Release of ATP from avian Muller glia cells in culture
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DOI：
10.1016/j.neuint.2010.12.019
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发表时间：
2011-02-01
影响因子：
4.2
通讯作者：
Marques Ventura, Ana Lucia
中科院分区：
文献类型：
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作者：
Loiola, Erick Correia;Marques Ventura, Ana Lucia
ATP 可以从神经元中释放并充当神经系统中的神经调节剂。除了神经元之外，皮质星形胶质细胞也能够以 Ca2+ 依赖性方式从酸性囊泡中释放 ATP。在目前的工作中，我们通过检查奎纳克林染色并测量纯化的米勒神经胶质细胞培养物中 ATP 的细胞外水平，研究了鸡胚视网膜米勒神经胶质细胞 ATP 的释放。我们的数据显示，神经胶质细胞可以用奎纳克林标记，这种反应可以通过将细胞与 1 μM 巴弗洛霉素 A1 或 2 μM 伊文思蓝（分别是液泡 ATP 酶和囊泡核苷酸转运蛋白的有效抑制剂）一起孵育来阻止。细胞孵育 5 分钟后，50 mM KCl 或 1 mM 谷氨酸能够减少细胞的奎纳克林染色，并使细胞外培养基中的 ATP 水平分别增加 77% 和 89.5%。在不含 MgCl2 但含有 2 mM 甘氨酸的培养基中，谷氨酸诱导的细胞外 ATP 升高可以通过 100 μM 红藻氨酸 (81.5%) 模拟，但不能通过 100 μM NMDA 模拟。然而，谷氨酸和红藻氨酸诱导的细胞外ATP水平的增加均被50μM的谷氨酸拮抗剂DNQX和MK-801阻断，表明NMDA和非NMDA受体都参与其中。将细胞与30μM BAPTA-AM或1μM巴弗洛霉素A1一起温育也可阻断由谷氨酸诱导的细胞外ATP积累。这些结果表明，谷氨酸通过激活 NMDA 和非 NMDA 受体，通过钙依赖性胞吐机制诱导视网膜 Muller 细胞释放 ATP。 (C) 2010 Elsevier Ltd. 保留所有权利。
ATP can be released from neurons and act as a neuromodulator in the nervous system. Besides neurons, cortical astrocytes also are capable of releasing ATP from acidic vesicles in a Ca2+-dependent way. In the present work, we investigated the release of ATP from Muller glia cells of the chick embryo retina by examining quinacrine staining and by measuring the extracellular levels of ATP in purified Muller glia cultures. Our data revealed that glial cells could be labeled with quinacrine, a reaction that was prevented by incubation of the cells with 1 mu M bafilomycin A1 or 2 mu M Evans blue, potent inhibitors of vacuolar ATPases and of the vesicular nucleotide transporter, respectively. Either 50 mM KCl or 1 mM glutamate was able to decrease quinacrine staining of the cells, as well as to increase the levels of ATP in the extracellular medium by 77% and 89.5%, respectively, after a 5 min incubation of the cells. Glutamate-induced rise in extracellular ATP could be mimicked by 100 mu M kainate (81.5%) but not by 100 mu M NMDA in medium without MgCl2 but with 2 mM glycine. However, both glutamate- and kainate-induced increase in extracellular ATP levels were blocked by 50 mu M of the glutamatergic antagonists DNQX and MK-801, suggesting the involvement of both NMDA and non-NMDA receptors. Extracellular ATP accumulation induced by glutamate was also blocked by incubation of the cells with 30 mu M BAPTA-AM or 1 mu M bafilomycin A1. These results suggest that glutamate, through activation of both NMDA and non-NMDA receptors, induces the release of ATP from retinal Muller cells through a calcium-dependent exocytotic mechanism. (C) 2010 Elsevier Ltd. All rights reserved.