Wang Lifang, Sato Hirofumi, Satoh Yohsuke, Tomioka Masahiro, Kunitomo Hirofumi, Iino Yuichi
Department of Biological Sciences, Graduate School of Science, and.
Department of Biological Sciences, Graduate School of Science, and
J Neurosci. 2017 Feb 22;37(8):2097-2111. doi: 10.1523/JNEUROSCI.1774-16.2017. Epub 2017 Jan 26.
Animals show various behaviors in response to environmental chemicals. These behaviors are often plastic depending on previous experiences. , which has highly developed chemosensory system with a limited number of sensory neurons, is an ideal model for analyzing the role of each neuron in innate and learned behaviors. Here, we report a new type of memory-dependent behavioral plasticity in Na chemotaxis generated by the left member of bilateral gustatory neuron pair ASE (ASEL neuron). When worms were cultivated in the presence of Na, they showed positive chemotaxis toward Na, but when cultivated under Na-free conditions, they showed no preference regarding Na concentration. Both channelrhodopsin-2 (ChR2) activation with blue light and up-steps of Na concentration activated ASEL only after cultivation with Na, as judged by increase in intracellular Ca Under cultivation conditions with Na, photoactivation of ASEL caused activation of its downstream interneurons AIY and AIA, which stimulate forward locomotion, and inhibition of its downstream interneuron AIB, which inhibits the turning/reversal behavior, and overall drove worms toward higher Na concentrations. We also found that the Gq signaling pathway and the neurotransmitter glutamate are both involved in the behavioral response generated by ASEL. Animals have acquired various types of behavioral plasticity during their long evolutionary history. prefers odors associated with food, but plastically changes its behavioral response according to previous experience. Here, we report a new type of behavioral response generated by a single gustatory sensory neuron, the ASE-left (ASEL) neuron. ASEL did not respond to photostimulation or upsteps of Na concentration when worms were cultivated in Na-free conditions; however, when worms were cultivated with Na, ASEL responded and inhibited AIB to avoid turning and stimulated AIY and AIA to promote forward locomotion, which collectively drove worms toward higher Na concentrations. Glutamate and the Gq signaling pathway are essential for driving worms toward higher Na concentrations.
动物会对环境化学物质表现出各种行为。这些行为通常具有可塑性，取决于以往的经历。线虫拥有高度发达的化学感应系统，且感觉神经元数量有限，是分析每个神经元在先天和习得行为中作用的理想模型。在此，我们报告了一种由双侧味觉神经元对ASE的左侧成员（ASEL神经元）产生的新型依赖记忆的行为可塑性，该可塑性存在于线虫对钠离子的趋化作用中。当线虫在有钠离子的环境中培养时，它们会表现出对钠离子的正向趋化性，但在无钠条件下培养时，它们对钠离子浓度没有偏好。蓝光激活通道视紫红质-2（ChR2）以及钠离子浓度的升高仅在有钠离子培养后才会激活ASEL，这可通过细胞内钙离子增加来判断。在有钠离子的培养条件下，ASEL的光激活会导致其下游中间神经元AIY和AIA的激活，它们会刺激向前运动，同时抑制其下游中间神经元AIB，AIB会抑制转向/反转行为，总体上驱使线虫趋向更高的钠离子浓度。我们还发现，Gq信号通路和神经递质谷氨酸都参与了ASEL产生的行为反应。动物在其漫长的进化历史中获得了各种类型的行为可塑性。线虫偏好与食物相关的气味，但会根据以往经验灵活改变其行为反应。在此，我们报告了一种由单个味觉感觉神经元，即ASE左侧（ASEL）神经元产生的新型行为反应。当线虫在无钠条件下培养时，ASEL对光刺激或钠离子浓度升高无反应；然而，当线虫在有钠条件下培养时，ASEL会做出反应并抑制AIB以避免转向，并刺激AIY和AIA以促进向前运动，这共同驱使线虫趋向更高的钠离子浓度。谷氨酸和Gq信号通路对于驱使线虫趋向更高的钠离子浓度至关重要。
