title: Nucleus accumbens GLP-1 receptors influence meal size and palatability.
abstract: Recent evidence suggests that the glucagon-like peptide-1 (GLP-1) neuronal projection to the nucleus accumbens core (NAcC) contributes to food intake control. To investigate the role of endogenous stimulation of GLP-1 receptors (GLP-1R) in NAcC, we examined the effects of the GLP-1R antagonist exendin-(9-39) (Ex9) on meal pattern and microstructure of ingestive behavior in rats. Intra-NAcC Ex9 treatment selectively increased meal size relative to vehicle in rats consuming 0.25 M sucrose solution or sweetened condensed milk. Microstructural analysis revealed effects of NAcC Ex9 on initial lick rate and the size and duration of licking bursts in rats consuming 0.1 or 0.25 M sucrose, suggesting that blockade of NAcC GLP-1R increases palatability. Because NAcC Ex9 did not affect licking for nonnutritive saccharin (0.1%), we suggest that the presence of nutrients in the gut may be required for endogenous stimulation of NAcC GLP-1R. Consistent with this, we also found that the meal size-suppressive effects of intragastric nutrient infusion were attenuated by NAcC delivery of Ex9 at a dose that had no effect when delivered alone. Analysis of licking patterns revealed that NAcC Ex9 did not reverse intragastric nutrient-induced suppression of burst number but rather blunted the effect of nutrient infusion on meal size primarily by increasing the size and duration of licking bursts. Together, our results suggest that NAcC Ex9 influences taste evaluation. We conclude that GLP-1 released in NAcC in response to gastrointestinal nutrients reduces the hedonic value of food.
authors.affiliation: Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Dossat
authors.forename: Ryan
authors.initials: R
authors.lastname: Diaz
authors.forename: Lindsay
authors.initials: L
authors.lastname: Gallo
authors.forename: Alyssa
authors.initials: A
authors.lastname: Panagos
authors.forename: Kristen
authors.initials: K
authors.lastname: Kay
authors.forename: Diana L
authors.initials: DL
authors.lastname: Williams
mesh_terms: D000818:Animals; D019422:Dietary Sucrose / Q000494:pharmacology; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D000067757:Glucagon-Like Peptide-1 Receptor; D008297:Male; D009434:Neural Pathways; D009714:Nucleus Accumbens / Q000166:cytology / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018027:Receptors, Glucagon / Q000037:antagonists & inhibitors / Q000502:physiology*; D012439:Saccharin / Q000494:pharmacology; D017552:Solitary Nucleus / Q000166:cytology / Q000502:physiology*; D013549:Sweetening Agents / Q000494:pharmacology; D013649:Taste / Q000502:physiology*
chemical_list: D019422:Dietary Sucrose; C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D010446:Peptide Fragments; D018027:Receptors, Glucagon; D013549:Sweetening Agents; C083773:exendin (9-39); D012439:Saccharin
keywords: glucagon-like peptide-1; licking microstructure; nucleus accumbens; palatability; satiation