Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, and.
Institute of Genetics and Biophysics of the National Research Council, 80131 Naples, Italy.
J Neurosci. 2014 Jul 9;34(28):9389-403. doi: 10.1523/JNEUROSCI.0012-14.2014.
Food is critical for survival. Many animals, including the nematode Caenorhabditis elegans, use sensorimotor systems to detect and locate preferred food sources. However, the signaling mechanisms underlying food-choice behaviors are poorly understood. Here, we characterize the molecular signaling that regulates recognition and preference between different food odors in C. elegans. We show that the major olfactory sensory neurons, AWB and AWC, play essential roles in this behavior. A canonical Gα-protein, together with guanylate cyclases and cGMP-gated channels, is needed for the recognition of food odors. The food-odor-evoked signal is transmitted via glutamatergic neurotransmission from AWC and through AMPA and kainate-like glutamate receptor subunits. In contrast, peptidergic signaling is required to generate preference between different food odors while being dispensable for the recognition of the odors. We show that this regulation is achieved by the neuropeptide NLP-9 produced in AWB, which acts with its putative receptor NPR-18, and by the neuropeptide NLP-1 produced in AWC. In addition, another set of sensory neurons inhibits food-odor preference. These mechanistic logics, together with a previously mapped neural circuit underlying food-odor preference, provide a functional network linking sensory response, transduction, and downstream receptors to process complex olfactory information and generate the appropriate behavioral decision essential for survival.
食物是生存的关键。许多动物，包括线虫秀丽隐杆线虫，使用感觉运动系统来检测和定位它们喜欢的食物来源。然而，食物选择行为背后的信号机制还了解甚少。在这里，我们描述了调节秀丽隐杆线虫识别和偏好不同食物气味的分子信号。我们表明，主要嗅觉感觉神经元 AWB 和 AWC 在这种行为中起着重要作用。一个典型的 G 蛋白，与鸟苷酸环化酶和 cGMP 门控通道一起，是识别食物气味所必需的。食物气味引发的信号通过 AWC 中的谷氨酸能神经传递，并通过 AMPA 和类似海人藻酸的谷氨酸受体亚基进行传递。相比之下，肽能信号对于不同食物气味之间的偏好产生是必需的，而对于气味的识别则是可有可无的。我们表明，这种调节是通过 AWB 中产生的神经肽 NLP-9 及其假定的受体 NPR-18 以及 AWC 中产生的神经肽 NLP-1 来实现的。此外，另一组感觉神经元抑制食物气味的偏好。这些机制逻辑，以及先前映射的食物气味偏好的神经回路，提供了一个功能网络，将感觉反应、转导和下游受体联系起来，以处理复杂的嗅觉信息并做出适当的行为决策，这对于生存至关重要。
