Insulin signalling plays a significant role in both developmental programmes and pathways modulating the neuronal signalling that controls adult behaviour. Here, we have investigated insulin signalling in food-associated behaviour in adult C. elegans by scoring locomotion and feeding on and off bacteria, the worm’s food. This analysis used mutants (daf-2, daf-18) of the insulin signalling pathway, and we provide evidence for an acute role for insulin signalling in the adult nervous system distinct from its impact on developmental programmes. Insulin receptor daf-2 mutants move slower than wild type both on and off food and showed impaired locomotory responses to food deprivation. This latter behaviour is manifest as a failure to instigate dispersal following prolonged food deprivation and suggests a role for insulin signalling in this adaptive response. Insulin receptor daf-2 mutants are also deficient in pharyngeal pumping on food and off food. Pharmacological analysis showed the pharynx of daf-2 is selectively compromised in its response to 5-HT compared to the excitatory neuropeptide FLP-17. By comparing the adaptive pharyngeal behaviour in intact worms and isolated pharyngeal preparations, we determined that an insulin-dependent signal extrinsic to the pharyngeal system is involved in feeding adaptation. Hence, we suggest that reactive insulin signalling modulates both locomotory foraging and pharyngeal pumping as the animal adapts to the absence of food. We discuss this in the context of insulin signalling directing a shift in the sensitivity of neurotransmitter systems to regulate the worm’s response to changes in food availability in the environment.

中文翻译：

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秀丽隐杆线虫中胰岛素受体 DAF-2 对摄食行为的上下文依赖性调节。

胰岛素信号在发育程序和调节控制成人行为的神经元信号的通路中都发挥着重要作用。在这里，我们通过对运动进行评分和进食和关闭细菌（蠕虫的食物）来研究成年秀丽隐杆线虫食物相关行为中的胰岛素信号传导。该分析使用了胰岛素信号通路的突变体（daf - 2、daf - 18），我们提供了证据表明胰岛素信号在成人神经系统中的急性作用与其对发育程序的影响不同。胰岛素受体daf - 2突变体在进食和禁食时的移动速度都比野生型慢，并且对食物剥夺的运动反应受损。后一种行为表现为在长期食物剥夺后未能促使分散，并表明胰岛素信号传导在这种适应性反应中的作用。胰岛素受体daf - 2突变体在食物和非食物的咽部泵送方面也存在缺陷。药理分析示咽部daf - 2与兴奋性神经肽 FLP-17 相比，它对 5-HT 的反应有选择性地受损。通过比较完整蠕虫和分离的咽部制剂的适应性咽部行为，我们确定咽部系统外在的胰岛素依赖性信号参与摄食适应。因此，我们建议当动物适应没有食物的情况时，反应性胰岛素信号调节运动觅食和咽部泵血。我们在胰岛素信号的背景下讨论了这一点，该信号指示神经递质系统的敏感性发生变化，以调节蠕虫对环境中食物供应变化的反应。