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Ventral tegmental area orexin 1 receptors promote palatable food intake and oppose postingestive negative feedback
- Source :
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 311:R592-R599
- Publication Year :
- 2016
- Publisher :
- American Physiological Society, 2016.
-
Abstract
- Hypothalamic orexin neurons project to numerous brain areas, including the ventral tegmental area (VTA), which is involved in motivation and food-seeking behavior. Here we address how exogenously administered orexin-A and endogenous orexin 1 receptor (OX1R) activation in the VTA affects feeding behavior. We hypothesized that orexin-A and OX1R antagonist SB334867 delivered to the VTA, at doses that were subthreshold for effect when injected into the ventricle, would affect intake of palatable foods in multiple test situations. We first used a hedonic feeding model in which satiated rats selectively consume a high-fat diet (HFD). Intra-VTA orexin-A stimulated additional consumption of chow and increased HFD intake in this model. In ad libitum-fed rats given daily 30-min test sessions, intra-VTA orexin-A also increased intake of HFD and 0.1 M sucrose. Further analysis of licking patterns revealed that that VTA orexin-A increased meal size and licking burst size only toward the end of the meal. Consistent with this finding, a subthreshold dose of VTA orexin-A prevented intake suppression induced by gastrointestinal nutrient infusion. Surprisingly, intra-VTA orexin-A had no effect on operant responding for sucrose pellets on a progressive ratio schedule of reinforcement. A role for endogenous VTA OX1R stimulation is supported by our finding that bilateral VTA injection of the selective OX1R antagonist SB334867 suppressed 0.1 M sucrose intake. Together, our data suggest that OX1R activity in the VTA facilitates food intake, potentially by counteracting postingestive negative feedback that would normally suppress feeding later in a meal.
- Subjects :
- Male
0301 basic medicine
medicine.medical_specialty
Physiology
Stimulation
Eating
03 medical and health sciences
Orexin-A
0302 clinical medicine
Orexin Receptors
Physiology (medical)
Internal medicine
mental disorders
medicine
Animals
Rats, Wistar
Feedback, Physiological
Motivation
Meal
Neural Control
Appetite Regulation
musculoskeletal, neural, and ocular physiology
Ventral Tegmental Area
digestive, oral, and skin physiology
Antagonist
Orexin receptor
Rats
Orexin
Ventral tegmental area
030104 developmental biology
medicine.anatomical_structure
Endocrinology
nervous system
Psychology
Licking
Reinforcement, Psychology
psychological phenomena and processes
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 15221490 and 03636119
- Volume :
- 311
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Accession number :
- edsair.doi.dedup.....974a908ec44d40cecb80435afcf81670