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dc.contributor.authorHead, Mitchell Antonyen_NZ
dc.contributor.authorJewett, David C.en_NZ
dc.contributor.authorGartner, Sarah N.en_NZ
dc.contributor.authorKlockars, Anicaen_NZ
dc.contributor.authorLevine, Allen S.en_NZ
dc.contributor.authorOlszewski, Pawel K.en_NZ
dc.date.accessioned2019-09-25T04:06:06Z
dc.date.available2019-05-15en_NZ
dc.date.available2019-09-25T04:06:06Z
dc.date.issued2019en_NZ
dc.identifier.citationHead, M. A., Jewett, D. C., Gartner, S. N., Klockars, A., Levine, A. S., & Olszewski, P. K. (2019). Effect of oxytocin on hunger discrimination. Frontiers in Endocrinology, 10. https://doi.org/10.3389/fendo.2019.00297en
dc.identifier.issn1664-2392en_NZ
dc.identifier.urihttps://hdl.handle.net/10289/12925
dc.description.abstractCentrally and peripherally administered oxytocin (OT) decreases food intake and activation of the endogenous OT systems, which is associated with termination of feeding. Evidence gathered thus far points to OT as a facilitator of early satiation, a peptide that reduces the need for a meal that has already begun. It is not known, however, whether OT can diminish a feeling of hunger, thereby decreasing a perceived need to seek calories. Therefore, in the current project, we first confirmed that intraperitoneal (i.p.) OT at 0.3–1 mg/kg reduces food intake in deprived and non-deprived rats. We then used those OT doses in a unique hunger discrimination protocol. First, rats were trained to discriminate between 22- and 2-h food deprivation (hungry vs. sated state) in a two-lever operant procedure. After rats acquired the discrimination, they were food-restricted for 22 h and given i.p. OT before a generalization test session. OT did not decrease 22-h deprivation-appropriate responding to match that following 2-h food deprivation, thus, it did not reduce the perceived level of hunger. In order to better understand the mechanisms behind this ineffectiveness of OT, we used c-Fos immunohistochemistry to determine whether i.p. OT activates a different subset of feeding-related brain sites under 22- vs. 2-h deprivation. We found that in sated animals, OT induces c-Fos changes in a broader network of hypothalamic and brain stem sites compared to those affected in the hungry state. Finally, by employing qPCR analysis, we asked whether food deprivation vs. sated state have an impact on OT receptor expression in the brain stem, a CNS “entry” region for peripheral OT. Fasted animals had significantly lower OT receptor mRNA levels than their ad libitum-fed counterparts. We conclude that OT does not diminish a feeling of hunger before a start of a meal. Instead OT's anorexigenic properties are manifested once consumption has already begun which is—at least to some extent—driven by changes in brain responsiveness to OT treatment in the hungry vs. fed state. OT should be viewed as a mediator of early satiation rather than as a molecule that diminishes perceived hunger.
dc.format.mimetypeapplication/pdf
dc.language.isoenen_NZ
dc.publisherFrontiers Media SAen_NZ
dc.rights© 2019 Head, Jewett, Gartner, Klockars, Levine and Olszewski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
dc.subjectScience & Technologyen_NZ
dc.subjectLife Sciences & Biomedicineen_NZ
dc.subjectEndocrinology & Metabolismen_NZ
dc.subjectoxytocinen_NZ
dc.subjectsatietyen_NZ
dc.subjecthungeren_NZ
dc.subjectfeedingen_NZ
dc.subjecthypothalamusen_NZ
dc.subjectC-FOS EXPRESSIONen_NZ
dc.subjectNEUROPEPTIDE-Yen_NZ
dc.subjectFOOD-INTAKEen_NZ
dc.subjectRECEPTOR AGONISTen_NZ
dc.subjectWEIGHT-LOSSen_NZ
dc.subjectRATSen_NZ
dc.subjectCHOLECYSTOKININen_NZ
dc.subjectDEPRIVATIONen_NZ
dc.subjectBEHAVIORen_NZ
dc.subjectOBESITYen_NZ
dc.titleEffect of oxytocin on hunger discriminationen_NZ
dc.typeJournal Article
dc.identifier.doi10.3389/fendo.2019.00297en_NZ
dc.relation.isPartOfFrontiers in Endocrinologyen_NZ
pubs.elements-id237494
pubs.publication-statusPublisheden_NZ
pubs.volume10en_NZ
uow.identifier.article-noARTN 297


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