O2-sensing neurons control CO2 response in C. elegans.
O2-sensing neurons control CO2 response in C. elegans.
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DOI：
10.1523/jneurosci.4541-12.2013
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发表时间：
2013-06-05
期刊：
影响因子：
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通讯作者：
Hallem EA
中科院分区：
文献类型：
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作者：
Carrillo MA;Guillermin ML;Rengarajan S;Okubo RP;Hallem EA
感官行为通常是灵活的，允许动物对不断变化的环境条件产生与上下文相适应的反应。为了研究行为灵活性的神经基础，我们研究了秀丽隐杆线虫对二氧化碳（CO2）反应的调节。CO2是许多动物的重要感觉线索，介导对食物、同种、捕食者和宿主的反应。In C.在线虫中，CO2反应受多态性神经肽受体NPR-1调节：具有npr-1的N2等位基因的动物避免CO2，而具有夏威夷（HW）等位基因或npr-1功能丧失（lf）突变的动物似乎对CO2几乎不敏感。在这里，我们表明，消融的氧（O2）敏感URX神经元的npr-1（lf）突变恢复CO2回避，这表明NPR-1使CO2回避通过抑制URX神经元。URX以前被证明是由环境中的O2增加激活。我们发现在npr-1（lf）突变体中，O2诱导的URX激活抑制CO2回避。此外，HW和npr-1（lf）动物在低O2条件下避免CO2，当URX不活动时。我们的研究结果表明，CO2响应是由O2敏感神经元的活动，并建议，O2依赖性调节CO2回避可能是一个生态相关的机制，线虫导航气体梯度。
Sensory behaviors are often flexible, allowing animals to generate context-appropriate responses to changing environmental conditions. To investigate the neural basis of behavioral flexibility, we examined the regulation of carbon dioxide (CO2) response in the nematode Caenorhabditis elegans. CO2 is a critical sensory cue for many animals, mediating responses to food, conspecifics, predators, and hosts. In C. elegans, CO2 response is regulated by the polymorphic neuropeptide receptor NPR-1: animals with the N2 allele of npr-1 avoid CO2, while animals with the Hawaiian (HW) allele or an npr-1 loss-of-function (lf) mutation appear virtually insensitive to CO2. Here we show that ablating the oxygen (O2)-sensing URX neurons in npr-1(lf) mutants restores CO2 avoidance, suggesting that NPR-1 enables CO2 avoidance by inhibiting URX neurons. URX was previously shown to be activated by increases in ambient O2. We find that in npr-1(lf) mutants, O2-induced activation of URX inhibits CO2 avoidance. Moreover, both HW and npr-1(lf) animals avoid CO2 under low O2 conditions, when URX is inactive. Our results demonstrate that CO2 response is determined by the activity of O2-sensing neurons, and suggest that O2-dependent regulation of CO2 avoidance is likely to be an ecologically relevant mechanism by which nematodes navigate gas gradients.