Bhatla Nikhil, Horvitz H Robert
Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Neuron. 2015 Feb 18;85(4):804-18. doi: 10.1016/j.neuron.2014.12.061. Epub 2015 Jan 29.
While gustatory sensing of the five primary flavors (sweet, salty, sour, bitter, and savory) has been extensively studied, pathways that detect non-canonical taste stimuli remain relatively unexplored. In particular, while reactive oxygen species cause generalized damage to biological systems, no gustatory mechanism to prevent ingestion of such material has been identified in any organism. We observed that light inhibits C. elegans feeding and used light as a tool to uncover molecular and neural mechanisms for gustation. Light can generate hydrogen peroxide, and we discovered that hydrogen peroxide similarly inhibits feeding. The gustatory receptor family members LITE-1 and GUR-3 are required for the inhibition of feeding by light and hydrogen peroxide. The I2 pharyngeal neurons increase calcium in response to light and hydrogen peroxide, and these responses require GUR-3 and a conserved antioxidant enzyme peroxiredoxin PRDX-2. Our results demonstrate a gustatory mechanism that mediates the detection and blocks ingestion of a non-canonical taste stimulus, hydrogen peroxide.
虽然对五种基本味觉（甜、咸、酸、苦和鲜味）的味觉感知已得到广泛研究，但检测非经典味觉刺激的途径仍相对未被探索。特别是，虽然活性氧会对生物系统造成广泛损害，但尚未在任何生物体中发现防止摄入此类物质的味觉机制。我们观察到光会抑制秀丽隐杆线虫的进食，并将光用作揭示味觉分子和神经机制的工具。光可以产生过氧化氢，我们发现过氧化氢同样会抑制进食。味觉受体家族成员LITE-1和GUR-3是光和过氧化氢抑制进食所必需的。I2咽部神经元会响应光和过氧化氢而增加钙含量，这些反应需要GUR-3和一种保守的抗氧化酶过氧化物酶PRDX-2。我们的结果证明了一种味觉机制，该机制介导对非经典味觉刺激过氧化氢的检测并阻止其摄入。
