Activation of transient receptor potential A1 channels by mustard oil, tetrahydrocannabinol and Ca2+ reveals different functional channel states
Activation of transient receptor potential A1 channels by mustard oil, tetrahydrocannabinol and Ca2+ reveals different functional channel states
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DOI：
10.1016/j.neuroscience.2008.04.048
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发表时间：
2008-07-17
期刊：
影响因子：
3.3
通讯作者：
Kim, D.
中科院分区：
文献类型：
--
作者：
Cavanaugh, E. J.;Simkin, D.;Kim, D.
我们最近的研究表明，刺激性化学物质如烯丙基异硫氰酸酯（AITC）激活瞬时受体电位全通道（TRPA 1）需要一种未鉴定的细胞溶质因子，其作用可以通过无机多磷酸盐模拟。因此，AITC和其他刺激性化学物质无法激活切除的斑块中的TRPA 1。目前尚不清楚TRPA 1是否会转换为对刺激性化学物质不敏感的构象，或者TRPA 1是否只是在胞质因子不存在时完全无功能且对所有激活剂不敏感。为了帮助区分这些可能性，测试了结构上与刺激性化学物质不同的Delta（9）-四氢大麻酚（THC）和Ca 2+对TRPA 1的AITC敏感和AITC不敏感状态的影响。在瞬时表达小鼠TRPA 1的HeLa细胞中，THC对TRPA 1的激活从细胞外侧（细胞附着; K-1/2 >20 μ M）是缓慢和微弱的，但从细胞内侧（由内向外; K-1/2，类似于0.7 μ M）是更快和更有效的，并且这不需要多磷酸盐的存在。在大鼠三叉神经元中观察到类似的结果。增加细胞外[Ca 2 +]从类似0-1-3 mM激活TRPA 1在细胞附着的补丁。使用毒胡萝卜素（Ca 2 +-ATPA酶抑制剂）和组胺（升高IP 3）升高细胞溶质[Ca 2 +]也激活了细胞贴附贴片中的TRPA 1。类似于刺激性化学物质，Ca 2+（1-5 μ M）未能激活TRPA 1在由内而外的补丁，除非多磷酸盐存在。这些结果表明，TRPA 1可以存在于不同的功能状态：天然状态（细胞附着的补丁）和非天然状态（切除的补丁）。THC可以激活TRPA 1，即使在没有多磷酸盐的情况下，而刺激性化学物质和Ca 2+需要它来激活。(C)2008年IBRO。由爱思唯尔有限公司出版。保留所有权利。
Our recent study has shown that activation of transient receptor potential All channel (TRPA1) by pungent chemicals such as allyl-isothlocyanate (AITC) requires an unidentified cytosolic factor whose action can be mimicked by inorganic polyphosphates. Thus, AITC and other pungent chemicals fail to activate TRPA1 in excised patches. It is unclear whether TRPA1 switches to a conformation that is insensitive to the pungent chemicals, or whether TRPA1 simply becomes completely non-functional and insensitive to all activators when the cytosolic factor is absent. To help distinguish between these possibilities, the effects of Delta(9)-tetrahydrocannabinol (THC) and Ca2+ that are structurally different from pungent chemicals were tested on AITC-sensitive and AITC-insensitive states of TRPA1. In HeLa cells transiently expressing mouse TRPA1, activation of TRPA1 by THC was slow and weak from the extracellular side (cell-attached; K-1/2 >20 mu M), but was faster and more potent from the intracellular side (inside-out; K-1/2, similar to 0.7 mu M), and this did not require the presence of a polyphosphate. Similar results were observed in rat trigeminal neurons. Increasing the extracellular [Ca2+] from similar to 0-1-3 mM activated TRPA1 in cell-attached patches. Elevation of cytosolic [Ca2+] using thapsigargin (inhibitor of Ca2+-ATPAse) and histamine (that elevates IP3) also activated TRPA1 in cell-attached patches. Similar to pungent chemicals, Ca2+ (1-5 mu M) failed to activate TRPA1 in inside-out patches, unless polyphosphates were present. These results show that TRPA1 can exist in different functional states: a native state (cell-attached patch) and a non-native state (excised patch). THC can activate TRPA1 even in the absence of polyphosphates, whereas pungent chemicals and Ca2+ require it for activation. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.