title: Chronic loss of melanin-concentrating hormone affects motivational aspects of feeding in the rat.
abstract: Current epidemic obesity levels apply great medical and financial pressure to the strenuous economy of obesity-prone cultures, and neuropeptides involved in body weight regulation are regarded as attractive targets for a possible treatment of obesity in humans. The lateral hypothalamus and the nucleus accumbens shell (AcbSh) form a hypothalamic-limbic neuropeptide feeding circuit mediated by Melanin-Concentrating Hormone (MCH). MCH promotes feeding behavior via MCH receptor-1 (MCH1R) in the AcbSh, although this relationship has not been fully characterized. Given the AcbSh mediates reinforcing properties of food, we hypothesized that MCH modulates motivational aspects of feeding.Here we show that chronic loss of the rat MCH-precursor Pmch decreased food intake predominantly via a reduction in meal size during rat development and reduced high-fat food-reinforced operant responding in adult rats. Moreover, acute AcbSh administration of Neuropeptide-GE and Neuropeptide-EI (NEI), both additional neuropeptides derived from Pmch, or chronic intracerebroventricular infusion of NEI, did not affect feeding behavior in adult pmch(+/+) or pmch(-/-) rats. However, acute administration of MCH to the AcbSh of adult pmch(-/-) rats elevated feeding behavior towards wild type levels. Finally, adult pmch(-/-) rats showed increased ex vivo electrically evoked dopamine release and increased limbic dopamine transporter levels, indicating that chronic loss of Pmch in the rat affects the limbic dopamine system.Our findings support the MCH-MCH1R system as an amplifier of consummatory behavior, confirming this system as a possible target for the treatment of obesity. We propose that MCH-mediated signaling in the AcbSh positively mediates motivational aspects of feeding behavior. Thereby it provides a crucial signal by which hypothalamic neural circuits control energy balance and guide limbic brain areas to enhance motivational or incentive-related aspects of food consumption.
authors.affiliation: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Joram D
authors.initials: JD
authors.lastname: Mul
authors.forename: Susanne E
authors.initials: SE
authors.lastname: la Fleur
authors.forename: Pim W
authors.initials: PW
authors.lastname: Toonen
authors.forename: Anthonieke
authors.initials: A
authors.lastname: Afrasiab-Middelman
authors.forename: Rob
authors.initials: R
authors.lastname: Binnekade
authors.forename: Dustin
authors.initials: D
authors.lastname: Schetters
authors.forename: Michel M M
authors.initials: MM
authors.lastname: Verheij
authors.forename: Robert M
authors.initials: RM
authors.lastname: Sears
authors.forename: Judith R
authors.initials: JR
authors.lastname: Homberg
authors.forename: Anton N M
authors.initials: AN
authors.lastname: Schoffelmeer
authors.forename: Roger A H
authors.initials: RA
authors.lastname: Adan
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: DiLeone
authors.forename: Taco J
authors.initials: TJ
authors.lastname: De Vries
authors.forename: Edwin
authors.initials: E
authors.lastname: Cuppen
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D006963:Hyperphagia / Q000503:physiopathology; D007028:Hypothalamic Hormones / Q000008:administration & dosage / Q000172:deficiency* / Q000378:metabolism* / Q000494:pharmacology; D007276:Injections, Intraventricular; D008543:Melanins / Q000008:administration & dosage / Q000494:pharmacology; D009042:Motivation / Q000187:drug effects / Q000502:physiology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology; D010907:Pituitary Hormones / Q000008:administration & dosage / Q000494:pharmacology; D011498:Protein Precursors / Q000172:deficiency* / Q000378:metabolism*; D051381:Rats; D012054:Reinforcement, Psychology
chemical_list: D004041:Dietary Fats; D007028:Hypothalamic Hormones; D008543:Melanins; D009842:Oligopeptides; D010907:Pituitary Hormones; D011498:Protein Precursors; C522850:neuropeptide EI; C059991:melanin-concentrating hormone precursors; C019463:melanin-concentrating hormone; D004298:Dopamine