Block of specific gap junction channel subtypes by 2-aminoethoxydiphenyl borate (2-APB)
Block of specific gap junction channel subtypes by 2-aminoethoxydiphenyl borate (2-APB)
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DOI：
10.1124/jpet.106.112045
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发表时间：
2006-12-01
影响因子：
3.5
通讯作者：
Spray, David C.
中科院分区：
文献类型：
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作者：
Bai, Donglin;del Corsso, Cristiane;Spray, David C.
氨基乙氧基二苯基硼酸酯（2-APB），肌醇1，4，5-三磷酸受体调节剂，抑制电容电流瞬变测量在正常大鼠肾脏和人胚肾293细胞，这些细胞之间的缝隙连接通道阻断的迹象。在这里，我们使用了双全细胞膜片钳方法，研究2-APB的行动所形成的间隙连接通道的通信缺陷的神经母细胞瘤细胞系（N2 A）中表达的选择性连接蛋白。2-APB剂量依赖性地可逆地阻断连接蛋白（Cx）50间隙连接通道的连接电流。2-APB对连接电流的浓度-抑制曲线显示IC_（50）为3.7 μ M，低于大多数缝隙连接抑制剂。在20 μ M的浓度下，2-APB还显著阻断了由Cx 26、Cx 30、Cx 36、Cx40和Cx45偶联的细胞对中的连接电导，但对表达Cx 32、Cx43和Cx46的细胞对中的偶联没有明显影响。尽管2-APB对Cx 36通道的浓度抑制曲线与Cx 50相似（Cx 36; IC 50，3.0 μ M），但Cx43（51.6 μ M）、Cx45（18.1 μ M）和Cx46（29.4 μ M）的IC 50值较高。2-APB的阻断作用并没有显著改变Cx 50间隙连接通道的跨连接电压依赖性门控，并且从耦合不良的Cx 50转染的N2 A细胞对的记录表明，2-APB降低了间隙连接通道开放的概率，而不改变主要状态的单通道电导。2-APB阻断不同连接蛋白形成的间隙连接通道的不同功效可能提供一个有用的工具，可以在间隙连接研究中用于选择性阻断某些间隙连接通道亚型。
Aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-triphosphate receptor modulator, inhibits capacitive current transients measured in normal rat kidney and human embryonic kidney 293 cells, an indication of blocking gap junction channels between these cells. Here, we used the dual whole-cell patch-clamp method to study the actions of 2-APB on gap junction channels formed by selected connexins expressed in a communication-deficient neuroblastoma cell line (N2A). 2-APB dose-dependently and reversibly blocked junctional currents of connexin (Cx) 50 gap junction channels. The concentration-inhibition curve of 2-APB on the junctional current indicated an IC50 of 3.7 mu M, lower than that of most gap junction inhibitors. At a concentration of 20 mu M, 2-APB also significantly blocked junctional conductance in cell pairs coupled by Cx26, Cx30, Cx36, Cx40, and Cx45 but did not appreciably affect coupling in cell pairs expressing Cx32, Cx43, and Cx46. Although concentration inhibition curves of 2-APB on Cx36 channels were similar to Cx50 (Cx36; IC50, 3.0 mu M), IC50 values were higher for Cx43 (51.6 mu M), Cx45 ( 18.1 mu M), and Cx46 ( 29.4 mu M). The blocking action of 2-APB did not substantially alter transjunctional voltage-dependent gating of Cx50 gap junction channels, and recordings from poorly coupled pairs of Cx50-transfected N2A cells indicated that 2-APB reduced gap junction channel open probability without changing the main state single-channel conductance. The differential efficacy of block by 2-APB of gap junction channels formed by different connexins may provide a useful tool that could be exploited in gap junction research to selectively block certain gap junction channel subtypes.