Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
Neuron. 2011 Sep 8;71(5):845-57. doi: 10.1016/j.neuron.2011.06.038.
Many nociceptors detect mechanical cues, but the ion channels responsible for mechanotransduction in these sensory neurons remain obscure. Using in vivo recordings and genetic dissection, we identified the DEG/ENaC protein, DEG-1, as the major mechanotransduction channel in ASH, a polymodal nociceptor in Caenorhabditis elegans. But DEG-1 is not the only mechanotransduction channel in ASH: loss of deg-1 revealed a minor current whose properties differ from those expected of DEG/ENaC channels. This current was independent of two TRPV channels expressed in ASH. Although loss of these TRPV channels inhibits behavioral responses to noxious stimuli, we found that both mechanoreceptor currents and potentials were essentially wild-type in TRPV mutants. We propose that ASH nociceptors rely on two genetically distinct mechanotransduction channels and that TRPV channels contribute to encoding and transmitting information. Because mammalian and insect nociceptors also coexpress DEG/ENaCs and TRPVs, the cellular functions elaborated here for these ion channels may be conserved.
许多伤害感受器可检测机械线索,但这些感觉神经元中负责机械转导的离子通道仍不清楚。我们使用体内记录和遗传剖析,将 DEG/ENaC 蛋白 DEG-1 鉴定为秀丽隐杆线虫 ASH(一种多模式伤害感受器)中的主要机械转导通道。但是,DEG-1 并非 ASH 中唯一的机械转导通道:deg-1 的缺失揭示了一种小电流,其特性与 DEG/ENaC 通道预期的不同。该电流与 ASH 中表达的两种 TRPV 通道无关。尽管这些 TRPV 通道的缺失会抑制对有害刺激的行为反应,但我们发现 TRPV 突变体中的机械感受器电流和电位基本上与野生型相同。我们提出 ASH 伤害感受器依赖于两种遗传上不同的机械转导通道,而 TRPV 通道有助于编码和传递信息。由于哺乳动物和昆虫伤害感受器也共表达 DEG/ENaCs 和 TRPVs,因此这些离子通道的细胞功能在这里可能是保守的。
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