Bargmann Cornelia I
Howard Hughes Medical Institute, Laboratory of Neural Circuits and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
WormBook. 2006 Oct 25:1-29. doi: 10.1895/wormbook.1.123.1.
C. elegans has a highly developed chemosensory system that enables it to detect a wide variety of volatile (olfactory) and water-soluble (gustatory) cues associated with food, danger, or other animals. Much of its nervous system and more than 5% of its genes are devoted to the recognition of environmental chemicals. Chemosensory cues can elicit chemotaxis, rapid avoidance, changes in overall motility, and entry into and exit from the alternative dauer developmental stage. These behaviors are regulated primarily by the amphid chemosensory organs, which contain eleven pairs of chemosensory neurons. Each amphid sensory neuron expresses a specific set of candidate receptor genes and detects a characteristic set of attractants, repellents, or pheromones. About 500-1000 different G protein-coupled receptors (GPCRs) are expressed in chemosensory neurons, and these may be supplemented by alternative sensory pathways as well. Downstream of the GPCRs, two signal transduction systems are prominent in chemosensation, one that uses cGMP as a second messenger to open cGMP-gated channels, and one that relies upon TRPV channels. These sensory pathways are modulated and fine-tuned by kinases and phosphatases. Chemosensory preferences can be modified by sensory adaptation, developmental history, and associative learning, allowing C. elegans to integrate context and experience into its behavior.
秀丽隐杆线虫拥有高度发达的化学感应系统，使其能够检测到与食物、危险或其他动物相关的多种挥发性（嗅觉）和水溶性（味觉）信号。其大部分神经系统以及超过5%的基因都用于识别环境中的化学物质。化学感应信号可引发趋化作用、快速回避、整体运动性的改变，以及进入和退出另一种滞育发育阶段。这些行为主要由两性化学感应器官调控，该器官包含11对化学感应神经元。每个两性感觉神经元都表达一组特定的候选受体基因，并检测一组特定的引诱剂、驱避剂或信息素。在化学感应神经元中大约表达500 - 1000种不同的G蛋白偶联受体（GPCR），并且这些受体可能还会有其他感觉通路作为补充。在GPCR的下游，有两个信号转导系统在化学感应中很突出，一个以cGMP作为第二信使来打开cGMP门控通道，另一个则依赖于TRPV通道。这些感觉通路由激酶和磷酸酶进行调节和微调。化学感应偏好可通过感觉适应、发育历程和联想学习来改变，这使得秀丽隐杆线虫能够将环境背景和经验融入其行为中。
