Potent block of Cx36 and Cx50 gap junction channels by mefloquine
Potent block of Cx36 and Cx50 gap junction channels by mefloquine
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DOI：
10.1073/pnas.0402044101
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发表时间：
2004-08-17
影响因子：
11.1
通讯作者：
Srinivas, M
中科院分区：
文献类型：
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作者：
Cruikshank, SJ;Hopperstadt, M;Srinivas, M
近年来，人们对脑、透镜、视网膜等组织中特异性缝隙连接蛋白（connexins）的功能研究产生了浓厚的兴趣。通过研究具有靶向连接蛋白缺失的基因敲除小鼠已经取得了一些进展。例如，这样的研究已经暗示了差距连接蛋白Cx 36在几个脑区域中同步神经元的节律活动。虽然敲除策略是信息丰富的，但它们可能是有问题的，因为在发育过程中有时会发生补偿性变化。因此，具有阻断特异性连接蛋白而对其他间隙连接或膜通道没有重大影响的药理学试剂将是极其有用的。我们表明，甲氟喹，抗疟疾药物，是这样的代理。它在低浓度下（IC 50约为300 nM）阻断转染的N2 A神经母细胞瘤细胞中表达的Cx 36通道。甲氟喹也阻断由透镜间隙连接蛋白Cx 50形成的通道（IC 50约为1.1 μ M）。然而，其他间隙连接（例如，Cx43、Cx 32和Cx 26）仅在浓度高10- 100倍时受到影响。为了进一步研究这种化合物的效用和特异性，我们表征了其在急性脑切片中的作用。25 μ M的甲氟喹阻断了新皮层切片中中间神经元之间的缝隙连接偶联，具有最小的非特异性作用。在这个浓度下，唯一的主要副作用是自发突触活动的增加。甲氟喹（25 μ M）引起诱发兴奋性或抑制性突触后电位没有显着变化，和内在的细胞特性也大多不受影响。因此，甲氟喹有望成为研究Cx 36和Cx 50功能的有用工具。
Recently, great interest has been shown in understanding the functional roles of specific gap junction proteins (connexins) in brain, lens, retina, and elsewhere. Some progress has been made by studying knockout mice with targeted connexin deletions. For example, such studies have implicated the gap junction protein Cx36 in synchronizing rhythmic activity of neurons in several brain regions. Although knockout strategies are informative, they can be problematic, because compensatory changes sometimes occur during development. Therefore, it would be extremely useful to have pharmacological agents that block specific connexins, without major effects on other gap junctions or membrane channels. We show that mefloquine, an antimalarial drug, is one such agent. It blocked Cx36 channels, expressed in transfected N2A neuroblastoma cells, at low concentrations (IC50 approximate to 300 nM). Mefloquine also blocked channels formed by the lens gap junction protein, Cx50 (IC50 approximate to 1.1 muM). However, other gap junctions (e.g., Cx43, Cx32, and Cx26) were only affected at concentrations 10- to 100-fold higher. To further examine the utility and specificity of this compound, we characterized its effects in acute brain slices. Mefloquine, at 25 muM, blocked gap junctional coupling between interneurons in neocortical slices, with minimal nonspecific actions. At this concentration, the only major side effect was an increase in spontaneous synaptic activity. Mefloquine (25 muM) caused no significant change in evoked excitatory or inhibitory postsynaptic potentials, and intrinsic cellular properties were also mostly unaffected. Thus, mefloquine is expected to be a useful tool to study the functional roles of Cx36 and Cx50.