Department of Anesthesiology, Chang Gung Memorial Hospital, 6 Jiapu Road, Puzi City, Chiayi County, 61363, Taiwan.
Department of Nursing, Chang Gung University of Science and Technology, 2 Jiapu Road, Puzi City, Chiayi County, 61363, Taiwan.
Fundam Clin Pharmacol. 2019 Dec;33(6):604-611. doi: 10.1111/fcp.12491. Epub 2019 Jul 4.
In a previous publication when we studied the purinergic receptor with which ATP interacted in mouse brain bEND.3 endothelial cells, we observed addition of 3 μm ARC 118925XX (ARC; selective P2Y antagonist) strongly suppressed ATP-triggered Ca release, suggesting the response was mediated via P2Y receptors. We here report ARC unexpectedly promoted substantial Ca influx even when ATP-triggered Ca release was largely inhibited. Since this large Ca influx may have important pharmacological significance, we proceeded to investigate its mechanism. ARC did not trigger intracellular Ca release thus suggesting Ca influx triggered by ARC was not store-operated. ARC-triggered Ca influx could be blocked by 1 mm Ni , a general Ca channel blocker, but not by SK&F 96365, a nonselective TRP channel blocker. Unexpectedly, ARC promoted influx of Na and La , but not Mn . This is a surprising finding, since Mn is conventionally used as a Ca surrogate ion (as it permeates Ca channel), and La is classically used as a potent Ca channel antagonist. Electrophysiological examination showed ARC did not stimulate any cation currents. Therefore, ARC opened, rather than a cation channel pore, an unidentified Ca influx pathway which was Na - and La -permeable but Mn -impermeable.
在之前的一项研究中，我们研究了与 ATP 在小鼠脑 bEND.3 内皮细胞中相互作用的嘌呤能受体，我们观察到添加 3μm 的 ARC 118925XX（ARC；选择性 P2Y 拮抗剂）强烈抑制了 ATP 触发的 Ca 释放，表明该反应是通过 P2Y 受体介导的。我们在这里报告说，ARC 出人意料地促进了大量的 Ca 内流，即使 ATP 触发的 Ca 释放被很大程度地抑制了。由于这种大量的 Ca 内流可能具有重要的药理学意义，我们继续研究其机制。ARC 没有触发细胞内 Ca 释放，因此表明 ARC 触发的 Ca 内流不是由储存操作引起的。1mm Ni（一种通用的 Ca 通道阻断剂）可以阻断 ARC 触发的 Ca 内流，但不能阻断 SK&F 96365（一种非选择性 TRP 通道阻断剂）。出乎意料的是，ARC 促进了 Na 和 La 的内流，但不能促进 Mn 的内流。这是一个令人惊讶的发现，因为 Mn 通常被用作 Ca 的替代离子（因为它可以渗透 Ca 通道），而 La 通常被用作一种有效的 Ca 通道拮抗剂。电生理学研究表明，ARC 没有刺激任何阳离子电流。因此，ARC 打开的不是阳离子通道孔，而是一种未知的 Ca 内流途径，该途径可通过 Na 和 La，但不能通过 Mn。
