Li Xiaonan, Sun Yuanjie, Gao Shan, Li Yan, Liu Li, Zhu Yan
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
iScience. 2023 Apr 7;26(5):106607. doi: 10.1016/j.isci.2023.106607. eCollection 2023 May 19.
Increasing pollution of heavy metals poses great risks to animals globally. Their survival likely relies on an ability to detect and avoid harmful heavy metal ions (HMIs). Currently, little is known about the neural mechanisms of HMI detection. Here, we show that and related species of actively avoid toxic HMIs at micromolar concentrations. The high sensitivity to HMIs is biologically relevant. Particularly, their sensitivity to cadmium is as high as that to the most bitter substance, denatonium. Detection of HMIs in food requires gustatory neurons but is independent of bitter-taste receptors. In these neurons, the ionotropic receptors IR76b, IR25a, and IR7a are required for the perception of heavy metals. Furthermore, IR47a mediates the activation of a distinct group of non- gustatory neurons elicited by HMIs. Together, our findings reveal a surprising taste quality represented by noxious metal ions.
重金属污染的加剧给全球动物带来了巨大风险。它们的生存可能依赖于检测和避免有害重金属离子（HMI）的能力。目前，人们对HMI检测的神经机制知之甚少。在这里，我们表明[具体物种]及其相关物种能够积极避免微摩尔浓度的有毒HMI。对HMI的高敏感性具有生物学意义。特别是，它们对镉的敏感性与对最苦的物质——苯甲地那铵的敏感性一样高。检测食物中的HMI需要[具体物种]的味觉神经元，但与苦味受体无关。在这些神经元中，离子型受体IR76b、IR25a和IR7a是感知重金属所必需的。此外，IR47a介导了由HMI引发的一组不同的非[具体物种]味觉神经元的激活。总之，我们的发现揭示了由有害金属离子代表的一种惊人的味觉特性。
