A novel mechanosensitive channel identified in sensory neurons
A novel mechanosensitive channel identified in sensory neurons
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DOI：
10.1111/j.1460-9568.2006.04802.x
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发表时间：
2006-05-01
影响因子：
3.4
通讯作者：
Oh, Uhtaek
中科院分区：
文献类型：
--
作者：
Cho, Hawon;Koo, Jae Yeon;Oh, Uhtaek
机械敏感（MS）通道是由不同类型的机械刺激门控的离子通道。感觉神经元中的MS通道被认为是身体感觉如触觉、压力、本体感觉和疼痛的分子换能器。以前，我们报道了两种类型的MS通道存在于感觉神经元。这些通道基于其激活的压力阈值被称为低阈值（LT）和高阈值（HT）MS通道。在这里，我们报告另一种类型的MS通道存在于感觉神经元。该通道由施加到贴片的低压激活（阈值类似于20 mmHg，类似于LT通道中的阈值）。然而，因为该通道具有比LT通道更小的单通道电导，所以新分类的MS通道现在被称为低阈值小电导（LTSC）通道。与具有向外整流电流的LT通道不同，LTSC的电流-电压关系是线性的。LTSC对一价阳离子和Ca 2+具有渗透性，并被MS通道阻断剂钆可逆地阻断。与LT通道不同，LTSC被前列腺素E2致敏，前列腺素E2是一种已知使伤害感受器对机械刺激敏感的炎症介质。LTSC通道主要存在于培养的小感觉神经元中。因此，这些结果表明，LTSC是一种独特类型的MS通道，不同于感觉神经元中的LT和HT通道，并且LTSC可能在介导包括疼痛在内的躯体感觉中发挥作用。
Mechanosensitive (MS) channels are ion channels gated by different types of mechanical stimuli. MS channels in sensory neurons are thought to be molecular transducers for somatic sensations such as touch, pressure, proprioception and pain. Previously, we reported that two types of MS channels are present in sensory neurons. These channels are termed low threshold (LT) and high threshold (HT) MS channels based on their pressure threshold for activation. Here, we report another type of MS channel present in sensory neurons. The channel is activated by low pressure applied to a patch (threshold similar to 20 mmHg, similar to that in the LT channel). However, because this channel has a smaller single-channel conductance than that of the LT channel, the newly classified MS channel is now called a low threshold small conductance (LTSC) channel. Unlike the LT channel, which has outwardly rectifying currents, the current-voltage relationship of the LTSC is linear. The LTSC was permeable to monovalent cations and Ca2+, and reversibly blocked by gadolinium, a blocker of MS channels. Unlike the LT channel, the LTSC was sensitized by prostaglandin E2, an inflammatory mediator that is known to sensitize nociceptors to mechanical stimuli. LTSC channels were found mostly in small cultured sensory neurons. Thus, these results suggest that the LTSC is a distinct type of MS channel that is different from the LT and HT channels in sensory neurons, and that LTSCs might play a role in mediating somatosensations, including pain.