美国哈佛医学院Stephen D. Liberles研究团队揭示了饥饿通过神经肽Y增强食物气味的吸引力。相关论文在线发表在2021年3月3日出版的《自然》杂志上。

在本研究中，研究人员揭示了一种神经元机制，其解释了与其他嗅觉信号相比，饥饿为什么有选择地促进了食物气味的吸引力。刺鼠基因相关蛋白（AgRP）神经元的光遗传激活增强了食物气味而非信息素的吸引力，分支特异性激活和抑制实验揭示了投射到脑室旁丘脑的关键作用。神经肽Y（NPY）或5型NPY受体（NPY5R）缺失小鼠在禁食后失去了对食物气味而非信息素的偏好性；在AGRP神经元中回补细胞特异性NPY恢复了饥饿诱导的食物气味吸引力。

此外，瞬时注射NPY在无需额外诱导下即可恢复食物气味偏好，这表明在行为表达过程中读取嗅觉回路而不是在气味学习过程中嗅觉回路的建立需要NPY。总之，这些发现表明，食物气味反应性神经元包含一个嗅觉子回路，该嗅觉子回路通过丘脑NPY释放来监测饥饿状态，并且提供了有关内部状态如何调节行为的机制见解。

研究人员表示，内部状态通过未知机制来控制嗅觉。表征食物、配偶、竞争者和捕食者的味道会激活平行神经回路，这些回路可能会因生理需要而灵活地改变行为结果。

附：英文原文

Title: Hunger enhances food-odour attraction through a neuropeptide Y spotlight

Author: Nao Horio, Stephen D. Liberles

Issue&Volume: 2021-03-03

Abstract: Internal state controls olfaction through poorly understood mechanisms. Odours that represent food, mates, competitors and predators activate parallel neural circuits that may be flexibly shaped by physiological need to alter behavioural outcome1. Here we identify a neuronal mechanism by which hunger selectively promotes attraction to food odours over other olfactory cues. Optogenetic activation of hypothalamic agouti-related peptide (AGRP) neurons enhances attraction to food odours but not to pheromones, and branch-specific activation and inhibition reveal a key role for projections to the paraventricular thalamus. Mice that lack neuropeptide Y (NPY) or NPY receptor type 5 (NPY5R) fail to prefer food odours over pheromones after fasting, and hunger-dependent food-odour attraction is restored by cell-specific NPY rescue in AGRP neurons. Furthermore, acute NPY injection immediately rescues food-odour preference without additional training, indicating that NPY is required for reading olfactory circuits during behavioural expression rather than writing olfactory circuits during odour learning. Together, these findings show that food-odour-responsive neurons comprise an olfactory subcircuit that listens to hunger state through thalamic NPY release, and more generally, provide mechanistic insights into how internal state regulates behaviour. Attraction to food odours is enhanced in mice that are experiencing hunger through a mechanism involving neuropeptide Y.

DOI: 10.1038/s41586-021-03299-4

Source: https://www.nature.com/articles/s41586-021-03299-4