Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea.
Robotics Engineering Department, DGIST, Daegu 42988, Republic of Korea.
Curr Biol. 2022 Jan 24;32(2):398-411.e4. doi: 10.1016/j.cub.2021.11.035. Epub 2021 Dec 13.
Animals detect and discriminate countless environmental chemicals for their well-being and survival. Although a single chemical can trigger opposing behavioral responses depending on its concentration, the mechanisms underlying such a concentration-dependent switching remain poorly understood. Here, we show that C. elegans exhibits either attraction or avoidance of the bacteria-derived volatile chemical dimethyl trisulfide (DMTS) depending on its concentration. This behavioral switching is mediated by two different types of chemosensory neurons, both of which express the DMTS-sensitive seven-transmembrane G protein-coupled receptor (GPCR) SRI-14. These two sensory neurons share downstream interneurons that process and translate DMTS signals via distinct glutamate receptors to generate the appropriate behavioral outcome. Thus, our results present one mechanism by which an animal connects two distinct types of chemosensory neurons detecting a common ligand to alternate downstream circuitry, thus efficiently switching between specific behavioral programs based on ligand concentration.
动物为了自身的福祉和生存，能够探测和辨别无数的环境化学物质。尽管一种化学物质的浓度会引发相反的行为反应，但这种浓度依赖性转换的机制仍知之甚少。在这里，我们表明，线虫根据其浓度表现出对细菌衍生的挥发性化学物质二甲基三硫（DMTS）的吸引或回避。这种行为转换由两种不同类型的化学感觉神经元介导，这两种神经元都表达 DMTS 敏感的七跨膜 G 蛋白偶联受体（GPCR）SRI-14。这两个感觉神经元共享下游中间神经元，通过不同的谷氨酸受体处理和翻译 DMTS 信号，以产生适当的行为结果。因此，我们的研究结果提供了一种机制，即动物将两种不同类型的化学感觉神经元连接起来，检测共同的配体，从而改变下游的电路，从而根据配体浓度有效地在特定的行为程序之间切换。
