ATP released via pannexin-1 hemichannels mediates bladder overactivity triggered by urothelial P2Y6 receptors
ATP released via pannexin-1 hemichannels mediates bladder overactivity triggered by urothelial P2Y6 receptors
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DOI：
10.1016/j.bcp.2013.11.007
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发表时间：
2014-01-15
影响因子：
5.8
通讯作者：
Correia-de-Sa, Paulo
中科院分区：
文献类型：
--
作者：
Alexandrina Timoteo, M.;Carneiro, Ines;Correia-de-Sa, Paulo
与尿路上皮 ATP 控制膀胱功能的众所周知的信号作用相反，尿嘧啶核苷酸（UTP 和/或 UDP）也发挥自分泌/旁分泌作用的假设最近才获得实验支持。尿路上皮细胞表达UDP敏感的P2Y(6)受体，但它们在控制膀胱活动中的作用大多被忽视。本研究旨在研究 PSB0474（一种稳定的 UDP 类似物，对 P2Y(6) 受体具有选择性）在体内调节麻醉大鼠尿动力学反应的能力。将 PSB0474 注入膀胱可增加排尿频率 (VF)，而不影响膀胱收缩的幅度 (A) 和持续时间 (At)。选择性 P2Y(6) 拮抗剂 MRS2578 可预防 PSB0474 诱导的膀胱过度活动。当这些药物应用于膀胱腔内时，PSB0474 产生的 VF 增加也被 pannexin-1 半通道抑制剂、(10)Panx 或carbenoxolone 阻断，但静脉注射时则不然。 H1152 降低半通道孔渗透性也可防止 PSB0474 诱导的膀胱过度活动，但胞吐作用抑制剂 Exo-1 没有活性。 PSB0474 使尿 ATP 含量增加 3 倍。半通道通透性对 PSB0474 诱导的 ATP 释放的影响通过实时荧光视频显微镜测量完整尿路上皮细胞在不存在和存在 MRS2578 或羧苯索龙的情况下对碘化丙啶的摄取来证明。共聚焦显微镜研究证实了 pannexin-1 和 P2Y(6) 受体在大鼠尿路上皮中的共定位。数据表明，P2Y(6) 受体的激活通过 pannexin-1 半通道从尿路上皮释放 ATP，间接导致麻醉大鼠膀胱过度活动。 (C) 2013 Elsevier Inc. 保留所有权利。
In contrast to the well-known signaling role of urothelial ATP to control bladder function, the hypothesis that uracil nucleotides (UTP and/or UDP) also exert autocrine/paracrine actions only recently gained experimental support. Urothelial cells express UDP-sensitive P2Y(6) receptors, yet their role in the control of bladder activity has been mostly neglected. This study was designed to investigate the ability of PSB0474, a stable UDP analogue which exhibits selectivity for P2Y(6) receptors, to modulate urodynamic responses in the anaesthetized rat in vivo. Instillation of PSB0474 into the bladder increased the voiding frequency (VF) without affecting the amplitude (A) and the duration (At) of bladder contractions. PSB0474-induced bladder overactivity was prevented by the selective P2Y(6) antagonist, MRS2578. The increase in the VF produced by PSB0474 was also blocked by inhibitors of pannexin-1 hemichannels, (10)Panx or carbenoxolone, when these drugs were applied inside the bladder lumen but not when they were administered intravenously. Reduction of hemichannels pore permeability with H1152 also prevented PSB0474-induced bladder overactivity, but the exocytosis inhibitor, Exo-1, was inactive. PSB0474 increased by 3-fold the urinary ATP content. Implication of hemichannels permeability on PSB0474-induced ATP release was demonstrated by real-time fluorescence video-microscopy measuring the uptake of propidium iodide by intact urothelial cells in the absence and in the presence of MRS2578 or carbenoxolone. Confocal microscopy studies confirmed the co-localization of pannexin-1 and P2Y(6) receptors in the rat urothelium. Data indicate that activation of P2Y(6) receptors causes bladder overactivity in the anaesthetized rat indirectly by releasing ATP from the urothelium via pannexin-1 hemichannels. (C) 2013 Elsevier Inc. All rights reserved.