Ghrelin enhances olfactory sensitivity and exploratory sniffing in rodents and humans

Jenny Tong, Erica Mannea, Pascaline Aimé, Paul T Pfluger, Chun Xia Yi, Tamara R. Castaneda, Harold W. Davis, Xueying Ren, Sarah Pixley, Stephen C Benoit, Karyne Julliard, Stephen C Woods, Tamas L Horvath, Mark M. Sleeman, David D'Alessio, Silvana Obici, Robert Frank, Matthias H. Tschöp

Research output: Contribution to journalArticleResearchpeer-review

129 Citations (Scopus)

Abstract

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 nonfood 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 neuro endocrine circuits controlling energy homeostasis.

Original languageEnglish
Pages (from-to)5841-5846
Number of pages6
JournalThe Journal of Neuroscience
Volume31
Issue number15
DOIs
Publication statusPublished - 13 Apr 2011
Externally publishedYes

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