Ghrelin enhances olfactory sensitivity and exploratory sniffing in rodents and humans.
Ghrelin enhances olfactory sensitivity and exploratory sniffing in rodents and humans.
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DOI：
10.1523/jneurosci.5680-10.2011
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发表时间：
2011-04-13
期刊：
影响因子：
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通讯作者：
Tschöp MH
中科院分区：
文献类型：
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作者：
Tong J;Mannea E;Aimé P;Pfluger PT;Yi CX;Castaneda TR;Davis HW;Ren X;Pixley S;Benoit S;Julliard K;Woods SC;Horvath TL;Sleeman MM;D'Alessio D;Obici S;Frank R;Tschöp MH
嗅觉是进食的一个组成部分，提供预测进食的线索。虽然嗅觉功能受到长时间禁食等因素的调节，但其潜在的神经机制仍然知之甚少。我们最近在大脑的嗅觉回路中发现了胃饥饿素受体。因此，我们研究了食欲刺激激素ghrelin在啮齿动物和人类嗅觉加工中的作用，验证了ghrelin降低嗅觉检测阈值并增强探索性嗅探的假设，这两者都与寻找食物有关。在大鼠中，脑室内胃饥饿素降低了气味检测阈值，增加了嗅探频率。在人类中，与生理盐水相比，全身胃饥饿素注入显著增强了对食物和非食物气味和空气的嗅觉强度，但不影响气味的愉悦度。这与气味检测的特定效果是一致的，而不是气味的享乐价值。总的来说，我们的研究结果表明，胃饥饿素刺激探索性嗅探，提高嗅觉敏感性，可能增强了定位、识别和选择食物的能力。这个新角色与胃饥饿素作为信号放大器的整体功能是一致的，它位于环境和营养线索以及控制能量稳态的神经内分泌回路之间的分子界面。
Olfaction is an integral part of feeding providing predictive cues that anticipate ingestion. Although olfactory function is modulated by factors such as prolonged fasting, the underlying neural mechanisms remain poorly understood. We recently identified ghrelin receptors in olfactory circuits in the brain. We therefore investigated the role of the appetite-stimulating hormone ghrelin in olfactory processing in rodents and humans, testing the hypothesis that ghrelin lowers olfactory detection thresholds and enhances exploratory sniffing, both being related to food-seeking. In rats, intracerebroventricular ghrelin decreased odor detection thresholds and increased sniffing frequency. In humans, systemic ghrelin infusions significantly enhanced sniff magnitudes in response to both food and non-food odorants and air in comparison to control saline infusions but did not affect the pleasantness ratings of odors. This is consistent with a specific effect on odor detection and not the hedonic value of odors. Collectively, our findings indicate that ghrelin stimulates exploratory sniffing and increases olfactory sensitivity, presumably enhancing the ability to locate, identify and select foods. This novel role is consistent with ghrelin’s overall function as a signal amplifier at the molecular interface between environmental and nutritional cues and neuroendocrine circuits controlling energy homeostasis.