Decrease in Operant Responding Under Obesogenic Diet Exposure is not Related to Deficits in Incentive or Hedonic Processes
Langue
EN
Article de revue
Ce document a été publié dans
Obesity. 2019, vol. 27, n° 2, p. 255-263
Résumé en anglais
OBJECTIVE: A growing body of evidence suggests that obesity could result from alterations in reward processing. In rodent models, chronic exposure to an obesogenic diet leads to blunted dopamine signaling and related ...Lire la suite >
OBJECTIVE: A growing body of evidence suggests that obesity could result from alterations in reward processing. In rodent models, chronic exposure to an obesogenic diet leads to blunted dopamine signaling and related incentive responding. This study aimed to determine which reward-related behavioral dimensions are actually impacted by obesogenic diet exposure. METHODS: Mice were chronically exposed to an obesogenic diet. Incentive and hedonic processes were tested through operant conditioning and licking microstructures, respectively. In parallel, mesolimbic dopamine transmission was assessed using microdialysis. RESULTS: Prolonged high-fat (HF) diet exposure led to blunted mesolimbic dopamine release, paralleled by a decrease in operant responding in all schedules tested. HF-fed and control animals similarly decreased their operant responding in an effort-based choice task, and HF-fed animals displayed an overall lower calorie intake in this task. Analysis of the licking microstructures during consumption of a freely accessible reward suggested a decrease in basal hunger and a potentiation of gastrointestinal inhibition in HF-fed animals, without changes in hedonic reactivity. CONCLUSIONS: These results suggest that the decrease in operant responding under prolonged HF diet exposure is mainly driven by decrease in hunger as well as stronger postingestive negative feedback mechanisms, rather than by a decrease in incentive or hedonic responses.< Réduire
Mots clés en anglais
Animals
Conditioning
Operant
Diet
High-Fat
Male
Mice
Unités de recherche