학술논문
Regulation of motivation for food by neuromedin U in the paraventricular nucleus and the dorsal raphe nucleus.
Document Type
Academic Journal
Author
McCue DL; Department of Neuroscience, University of Texas Medical Branch, Galveston, TX, USA.; Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA.; Kasper JM; Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA.; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA.; Hommel JD; Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA.; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA.
Source
Publisher: Nature Pub. Group Country of Publication: England NLM ID: 101256108 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1476-5497 (Electronic) Linking ISSN: 03070565 NLM ISO Abbreviation: Int J Obes (Lond) Subsets: MEDLINE
Subject
Language
English
Abstract
Background: Motivation for high-fat food is thought to contribute to excess caloric intake in obese individuals. A novel regulator of motivation for food may be neuromedin U (NMU), a highly-conserved neuropeptide that influences food intake. Although these effects of NMU have primarily been attributed to signaling in the paraventricular nucleus of the hypothalamus (PVN), NMU has also been found in other brain regions involved in both feeding behavior and motivation. We investigate the effects of NMU on motivation for food and food intake, and identify the brain regions mediating these effects.
Methods: The motivational state for a particular reinforcer (e.g., high-fat food) can be assessed using a progressive-ratio schedule of reinforcement under which an increasing number of lever presses are required to obtain subsequent reinforcers. Here, we have used a progressive-ratio operant responding paradigm in combination with an assessment of cumulative food intake to evaluate the effects of NMU administration in rats, and identify the brain regions mediating these effects.
Results: We found that peripheral administration of NMU decreases operant responding for high-fat food in rats. Evaluation of Fos-like immunoreactivity in response to peripheral NMU indicated the PVN and dorsal raphe nucleus (DRN) as sites of action for NMU. NMU infusion into either region mimics the effects of peripheral NMU on food intake and operant responding for food. NMU-containing projections from the lateral hypothalamus (LH) to the PVN and DRN were identified as an endogenous source of NMU.
Conclusions: These results identify the DRN as a site of action for NMU, demonstrate that the LH provides endogenous NMU to the PVN and DRN and implicate NMU signaling in the PVN and DRN as a novel regulator of motivation for high-fat foods.
Competing Interests: The authors declare no conflict of interest.
Methods: The motivational state for a particular reinforcer (e.g., high-fat food) can be assessed using a progressive-ratio schedule of reinforcement under which an increasing number of lever presses are required to obtain subsequent reinforcers. Here, we have used a progressive-ratio operant responding paradigm in combination with an assessment of cumulative food intake to evaluate the effects of NMU administration in rats, and identify the brain regions mediating these effects.
Results: We found that peripheral administration of NMU decreases operant responding for high-fat food in rats. Evaluation of Fos-like immunoreactivity in response to peripheral NMU indicated the PVN and dorsal raphe nucleus (DRN) as sites of action for NMU. NMU infusion into either region mimics the effects of peripheral NMU on food intake and operant responding for food. NMU-containing projections from the lateral hypothalamus (LH) to the PVN and DRN were identified as an endogenous source of NMU.
Conclusions: These results identify the DRN as a site of action for NMU, demonstrate that the LH provides endogenous NMU to the PVN and DRN and implicate NMU signaling in the PVN and DRN as a novel regulator of motivation for high-fat foods.
Competing Interests: The authors declare no conflict of interest.