Cholecystokinin-like Peptide Mediates Satiety by Inhibiting Sugar Attraction

SUMMARY Feeding is essential for animal survival and reproduction and is regulated by both internal states and external stimuli. However, little is known about how internal states influence the perception of external sensory cues that regulate feeding behavior. Here, we investigated the neuronal and molecular mechanisms behind nutritional state-mediated regulation of gustatory perception in control of feeding behavior in the brown planthopper and Drosophila . We found that feeding increases the expression of the cholecystokinin-like peptide, sulfakinin (SK), and the activity of a set of SK-expressing neurons. Starvation elevates the transcription of the sugar receptor Gr64f and SK negatively regulates the expression of Gr64f in both insects. This Gr64f regulation is by direct action of SK neurons on Gr64f-expressing neurons of the proboscis and proleg tarsi that co-express the SK receptor CCKLR-17D3. Our findings thus demonstrate how nutritional state induces peptide signaling to modulate sweet perception and thereby feeding behavior.