| Ghrelin Signaling in the Ventral Hippocampus Stimulates Learned and Motivational Aspects of Feeding via PI3K-Akt Signaling. | |
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MedLine Citation:
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PMID: 22884970 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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BACKGROUND: The stomach-derived hormone ghrelin drives higher-order feeding processes related to food reward and food seeking via central nervous system signaling at its receptor (GHSR1A). The specific nuclei mediating these effects are only partially understood. Here, we use a rat model to examine whether ghrelin signaling in the ventral subregion of the hippocampus (VHPC), a brain substrate of recent interest in energy balance control, affects learned and motivational aspects of feeding behavior. METHODS: The effects of VHPC ghrelin administration were examined on feeding-relevant behavioral paradigms, including meal pattern analysis, operant lever pressing for sucrose, and conditioned stimulus-induced feeding. The intracellular signaling and downstream neuronal pathways stimulated by VHPC GHSR1A activation were assessed with immunoblot analysis and behavioral pharmacology. RESULTS: Ghrelin delivery to the VHPC but not the dorsal hippocampus increased food intake primarily by increasing meal frequency. Intra-VHPC ghrelin delivery also increased willingness to work for sucrose and increased spontaneous meal initiation in nondeprived rats after the presentation of a conditioned stimulus that previously signaled meal access when the rats were food-restricted. The food intake enhancing effects of VHPC ghrelin were blocked by co-administration of a phosphoinositide 3-kinase (PI3K) inhibitor (LY294002). Immunoblot analyses provided complementary support for ghrelin activated PI3K-Akt signaling in the VHPC and revealed that this activation is blunted with high-fat diet consumption. Other immunoblot results show that VHPC GHSR1A signaling activates downstream dopaminergic activity in the nucleus accumbens. CONCLUSIONS: These findings illuminate novel neuronal and behavioral mechanisms mediating ghrelinergic control of cognitive aspects of feeding control. |
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Authors:
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Scott E Kanoski; Samantha M Fortin; Katie M Ricks; Harvey J Grill |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-8-9 |
Journal Detail:
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Title: Biological psychiatry Volume: - ISSN: 1873-2402 ISO Abbreviation: Biol. Psychiatry Publication Date: 2012 Aug |
Date Detail:
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Created Date: 2012-8-13 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0213264 Medline TA: Biol Psychiatry Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved. |
Affiliation:
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Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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