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Pitoy M, Gauthier L, Debatisse J, Maulavé J, Météreau E, Beaudoin M, Portier K, Sgambato V, Billard T, Zimmer L, Lancelot S, Tremblay L. SB-258585 reduces food motivation while blocking 5-HT 6 receptors in the non-human primate striatum. Prog Neuropsychopharmacol Biol Psychiatry 2024; 131:110970. [PMID: 38354894 DOI: 10.1016/j.pnpbp.2024.110970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/09/2024] [Accepted: 02/11/2024] [Indexed: 02/16/2024]
Abstract
The interest in new 5-HT₆ agents stems from their ability to modulate cognition processing, food motivation and anxiety-like behaviors. While these findings come primarily from rodent studies, no studies on primates have been published. Furthermore, our understanding of where and how they act in the brain remains limited. Although the striatum is involved in all of these processes and expresses the highest levels of 5-HT₆ receptors, few studies have focused on it. We thus hypothesized that 5-HT6 receptor blockade would influence food motivation and modulate behavioral expression in non-human primates through striatal 5-HT6 receptors. This study thus aimed to determine the effects of acute administration of the SB-258585 selective 5-HT6 receptor antagonist on the feeding motivation and behaviors of six male macaques. Additionally, we investigated potential 5-HT6 targets using PET imaging to measure 5-HT6 receptor occupancy throughout the brain and striatal subregions. We used a food-choice task paired with spontaneous behavioral observations, checking 5-HT6 receptor occupancy with the specific PET imaging [18F]2FNQ1P radioligand. We demonstrated, for the first time in non-human primates, that modulation of 5-HT6 transmission, most likely through the striatum (the putamen and caudate nucleus), significantly reduces food motivation while exhibiting variable, weaker effects on behavior. While these results are consistent with the literature showing a decrease in food intake in rodents and proposing that 5-HT6 receptor antagonists can be used in obesity treatment, they question the antagonists' anxiolytic potential.
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Affiliation(s)
- Mathilde Pitoy
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France; Hospices Civils de Lyon, 3 Quai des Célestins, 69002 Lyon, France.
| | - Lisa Gauthier
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France
| | - Justine Debatisse
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Centre de Recherche en Neurosciences de Lyon, CNRS UMR5292, INSERM U1028, Lyon, France
| | - Julie Maulavé
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France
| | - Elise Météreau
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Hospices Civils de Lyon, 3 Quai des Célestins, 69002 Lyon, France
| | - Maude Beaudoin
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France
| | - Karine Portier
- Université de Lyon, VetAgro Sup, CREFAC, 69280 Marcy l'Etoile, France; UCBL, CNRS, INSERM, CRNL U1028 UMR5292, Trajectoire, Lyon, 69500 Bron, France
| | - Véronique Sgambato
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France
| | | | - Luc Zimmer
- Université Claude-Bernard Lyon1, 69100 Villeurbanne, France; Hospices Civils de Lyon, 3 Quai des Célestins, 69002 Lyon, France; Centre de Recherche en Neurosciences de Lyon, CNRS UMR5292, INSERM U1028, Lyon, France; CERMEP-Imagerie du Vivant, 59 Bd Pinel, 69677 Bron, France
| | - Sophie Lancelot
- Université Claude-Bernard Lyon1, 69100 Villeurbanne, France; Hospices Civils de Lyon, 3 Quai des Célestins, 69002 Lyon, France; Centre de Recherche en Neurosciences de Lyon, CNRS UMR5292, INSERM U1028, Lyon, France; CERMEP-Imagerie du Vivant, 59 Bd Pinel, 69677 Bron, France
| | - Léon Tremblay
- Institut des Sciences Cognitives Marc Jeannerod, UMR-5229 CNRS, 67 boulevard Pinel, 69675 Bron Cedex, France; Université Claude-Bernard Lyon1, 69100 Villeurbanne, France.
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Chen L, Thapaliya G, Papantoni A, Benson L, Carnell S. Neural correlates of appetite in adolescents. Appetite 2023; 191:107076. [PMID: 37806450 PMCID: PMC10997743 DOI: 10.1016/j.appet.2023.107076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
Appetitive characteristics are associated with child adiposity, but their biological underpinnings are unclear. We sought to investigate the neural correlates of psychometric and behavioral measures of appetitive characteristics in youth. Adolescents (14-18y; 39F, 37M) varying in familial obesity risk and body weight (20% with overweight, 24% with obesity) viewed pictures of high energy-density (ED) foods, low-ED foods and non-foods during fMRI scanning on two separate days. On one day participants consumed a 474 ml preload of water (0 kcal, fasted) and on another (counter-balanced) 474 ml milkshake (480 kcal, fed), before scanning. A multi-item ad libitum meal (ALM) followed scanning. Parents completed Child Eating Behavior Questionnaire (CEBQ) sub-scales assessing food approach and food self-regulation. Caloric compensation was calculated as the percentage of preload intake compensated for by down-regulation of ALM intake in the fed vs. fasted condition. Analyses correcting for multiple comparisons demonstrated that, for the fasted condition, higher CEBQ Food Responsiveness scores were associated with greater activation to high-ED (vs. low-ED) foods in regions implicated in food reward (insula, rolandic operculum, putamen). In addition, higher caloric compensation was associated with greater fed vs. fasted activations in response to foods (vs. non-foods) in thalamus and supramarginal gyrus. Uncorrected analyses provided further support for associations of different measures of appetitive characteristics with brain responses to food cues in each condition. Measures of appetitive characteristics demonstrated overlapping and distinct associations with patterns of brain activation elicited by food cues in fasted and fed states. Understanding the neural basis of appetitive characteristics could aid development of biobehaviorally-informed obesity interventions.
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Affiliation(s)
- L Chen
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA
| | - G Thapaliya
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA
| | - A Papantoni
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA
| | - L Benson
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA
| | - S Carnell
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, USA.
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Bunney PE, Smethells JR, LeSage MG. Substitutability of nicotine and sucrose in rats: A behavioral economic analysis. Pharmacol Biochem Behav 2023; 232:173635. [PMID: 37714222 PMCID: PMC10937332 DOI: 10.1016/j.pbb.2023.173635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/24/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
Despite considerable evidence suggesting that sweet foods are a substitute for nicotine in humans, no formal behavioral economic analysis of this interrelationship has been conducted in nonhumans. The purpose of the present study was to examine this phenomenon in rats using concurrent schedules of sucrose pellet, chow pellet, and nicotine reinforcer delivery. Rats responded on separate levers that delivered sucrose pellets, chow pellets, or nicotine infusions under concurrent fixed-ratio (FR) 1 schedules for each commodity within a closed economy. Following stable food and nicotine intake, the unit price of either sucrose or nicotine (the primary commodity) was increased while the two alternative commodities remained unchanged. Substitution was quantified using a behavioral economic cross-price model, as well as a novel commodity relation index that normalizes consumption of dissimilar commodities. Asymmetrical partial substitution was observed, wherein sucrose served as a partial substitute for nicotine, but nicotine failed to substitute for sucrose. Moreover, sucrose was a stronger partial substitute for nicotine than chow in most rats. These findings indicate that substitution of food for nicotine depends on the type of food. These findings mirror the selective increase in carbohydrate intake that can occur during smoking cessation and demonstrate a behavioral economic mechanism that may mediate it.
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Affiliation(s)
- Patricia E Bunney
- Hennepin Healthcare Research Institute, Minneapolis, MN, USA; Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - John R Smethells
- Hennepin Healthcare Research Institute, Minneapolis, MN, USA; Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Mark G LeSage
- Hennepin Healthcare Research Institute, Minneapolis, MN, USA; Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Departments of Pharmacology and Psychology, University of Minnesota, Minneapolis, MN, USA.
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Singh U, Saito K, Khan MZ, Jiang J, Toth BA, Rodeghiero SR, Dickey JE, Deng Y, Deng G, Kim YC, Cui H. Collateralizing ventral subiculum melanocortin 4 receptor circuits regulate energy balance and food motivation. Physiol Behav 2023; 262:114105. [PMID: 36736416 PMCID: PMC9981473 DOI: 10.1016/j.physbeh.2023.114105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023]
Abstract
Hippocampal dysfunction is associated with major depressive disorder, a serious mental illness characterized by not only depressed mood but also appetite disturbance and dysregulated body weight. However, the underlying mechanisms by which hippocampal circuits regulate metabolic homeostasis remain incompletely understood. Here we show that collateralizing melanocortin 4 receptor (MC4R) circuits in the ventral subiculum (vSUB), one of the major output structures of the hippocampal formation, affect food motivation and energy balance. Viral-mediated cell type- and projection-specific input-output circuit mapping revealed that the nucleus accumbens shell (NAcSh)-projecting vSUBMC4R+ neurons send extensive collateral projections of to various hypothalamic nuclei known to be important for energy balance, including the arcuate, ventromedial and dorsomedial nuclei, and receive monosynaptic inputs mainly from the ventral CA1 and the anterior paraventricular nucleus of thalamus. Chemogenetic activation of NAcSh-projecting vSUBMC4R+neurons lead to increase in motivation to obtain palatable food without noticeable effect on homeostatic feeding. Viral-mediated restoration of MC4R signaling in the vSUB partially restores obesity in MC4R-null mice without affecting anxiety- and depression-like behaviors. Collectively, these results delineate vSUBMC4R+ circuits to the unprecedented level of precision and identify the vSUBMC4R signaling as a novel regulator of food reward and energy balance.
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Affiliation(s)
- Uday Singh
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Kenji Saito
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Michael Z. Khan
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Jingwei Jiang
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Brandon A. Toth
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Samuel R. Rodeghiero
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Jacob E. Dickey
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Yue Deng
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Guorui Deng
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Young-Cho Kim
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Huxing Cui
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, United States; F.O.E. Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, United States.
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Smith KR, Jansen E, Thapaliya G, Aghababian AH, Chen L, Sadler JR, Carnell S. The influence of COVID-19-related stress on food motivation. Appetite 2021; 163:105233. [PMID: 33819527 PMCID: PMC9190771 DOI: 10.1016/j.appet.2021.105233] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 02/15/2021] [Accepted: 03/23/2021] [Indexed: 12/22/2022]
Abstract
The COVID-19 pandemic and public health measures to reduce its transmission have increased stress. Stress is associated with alterations in eating behavior which may be partly driven by effects on food-related motivation. To investigate effects of COVID-related stress on food motivation, we recruited adults (N = 429; 272 F, 157 M) to complete an online survey via Amazon MTurk in May 2020. Current COVID-related stress, retrospective pre-COVID stress, and motivation in relation to individualized preferred foods from five categories (sweet snacks, fruit, savory snacks, vegetables, and fast food) were assessed. Food motivation measures included willingness to wait, willingness to expend low effort [finger taps], willingness to expend high effort [jumping jacks], and willingness to pay for hypothetical delivery of the food item. Food motivation for each food type was assessed using a novel instrument designed for brief assessment of multiple aspects of food motivation across multiple food types. Participants were willing to pay the most for fast food followed by sweet snacks, and willing to wait longer for sweet snacks relative to other food types. While fast food and sweets also generated the most willingness to expend high and low effort, willingness to expend low effort for fruit was similar to that for fast food and sweets, and willingness to expend high effort for fruit was comparable to that for fast food. Participants were least willing to pay or expend low effort for vegetables. Higher COVID-related stress levels were associated with willingness to expend more effort and pay more for food items. These data collected during the pandemic demonstrate that highly processed and sweet foods have high motivating value across multiple measures of motivation, and COVID-related stress increases food motivation across food categories. Interventions to mitigate stress and target the link between stress and overeating may help to limit the effects of the COVID-19 pandemic on obesity.
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Affiliation(s)
- Kimberly R Smith
- Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Elena Jansen
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gita Thapaliya
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anahys H Aghababian
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Liuyi Chen
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jennifer R Sadler
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Susan Carnell
- Division of Child & Adolescent Psychiatry, Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Selleck RA, Giacomini J, Buchholtz BD, Lake C, Sadeghian K, Baldo BA. Modulation of appetitive motivation by prefrontal cortical mu-opioid receptors is dependent upon local dopamine D1 receptor signaling. Neuropharmacology 2018; 140:302-309. [PMID: 30086291 DOI: 10.1016/j.neuropharm.2018.07.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022]
Abstract
Opioid neurotransmission has been implicated in psychiatric disorders featuring impaired control over appetitive motivation, such as addiction and binge-eating disorder. We have previously shown that infusions of the μ-opioid receptor (μOR) agonist DAMGO into the ventromedial prefrontal cortex (vmPFC) induced hyperphagia, increased motor activity, and augmented sucrose-reinforced responding in the task progressive ratio (PR) task, which assesses the motivational value of an incentive. These effects were not reproduced by intra-PFC infusion of a variety of dopamine (DA) agonists and antagonists, suggesting that manipulation of intra-PFC DA systems alone is not sufficient to reproduce μOR-like effects. Nevertheless, this does not rule out interactions between PFC DA and μ-opioid systems. Here we used intra-vmPFC drug cocktails containing DAMGO and SCH 23390 (a DA D1 receptor antagonist) to determine whether increases in appetitive motivation and motor activity elicited by intra-vmPFC μOR stimulation require intact signaling through vmPFC D1 receptors. Blockade of D1 receptors with SCH 23390 attenuated the enhancement of PR breakpoint, and increases in exploratory-like behavior and feeding initiation elicited by intra-vmPFC μOR stimulation. These results establish that intra-vmPFC D1 signaling is required for the expression of behavioral effects evoked by μOR stimulation within the PFC, and further suggest that D1 tone plays an enabling or permissive role in the expression of μOR -elicited effects. Simultaneous targeting of both μ-opioid and D1 systems may represent a more efficacious treatment strategy (compared to μOR blockade alone) for psychiatric disorders characterized by dysregulated appetitive motivation.
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Affiliation(s)
- Ryan A Selleck
- Dept. Cellular & Molecular Pharmacology, Rosalind Franklin, Univ.of Medicine & Science, USA
| | - Juliana Giacomini
- Physiology Graduate Training Program, Univ. Wisconsin-Madison, School of Medicine &Public Health, USA
| | | | - Curtis Lake
- College of Agricultural & Life Sciences, Univ. Wisconsin-Madison, USA
| | - Ken Sadeghian
- Dept. Psychiatry, Univ. Wisconsin-Madison, School of Medicine & Public Health, USA
| | - Brian A Baldo
- Dept. Psychiatry, Univ. Wisconsin-Madison, School of Medicine & Public Health, USA.
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López-Ferreras L, Richard JE, Anderberg RH, Nilsson FH, Olandersson K, Kanoski SE, Skibicka KP. Ghrelin's control of food reward and body weight in the lateral hypothalamic area is sexually dimorphic. Physiol Behav 2017; 176:40-9. [PMID: 28213203 DOI: 10.1016/j.physbeh.2017.02.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/18/2017] [Accepted: 02/10/2017] [Indexed: 12/18/2022]
Abstract
Ghrelin is a stomach-produced hormone that stimulates ingestive behavior and increases motivated behavior to obtain palatable foods. Ghrelin receptors (growth hormone secretagogue receptors; Ghsr) are expressed in the lateral hypothalamic area (LHA), and LHA-targeted ghrelin application increases ingestive behavior in male rodents. However, the effects of LHA ghrelin signaling in females are unexplored. Here we investigated whether LHA ghrelin signaling is necessary and sufficient for control of ingestive and motivated behavior for food in male and female rats. Ghrelin delivered to the LHA increased food intake and motivated behavior for sucrose in both male and female rats, whereas increased food-seeking behavior and body weight were only observed in females. Females had slightly higher Ghsr levels in the LHA compared to males, and importantly, acute blockade of the Ghsr in the LHA significantly reduced food intake, body weight, and motivated behavior for sucrose in female but not male rats. Chronic LHA Ghsr reduction in female rats achieved by RNA inference-mediated Ghsr knockdown, resulting in a 25% reduction in LHA Ghsr mRNA, abolished the reward-driven behavioral effects of LHA-targeted ghrelin, but was not sufficient to affect baseline food intake or food reward responding. Collectively we show that ghrelin acts in the LHA to alter ingestive and motivated behaviors in a sex-specific manner.
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Lundgren JD, Patrician TM, Breslin F, Martin L, Donnelly JE, Savage CR. Evening hyperphagia and food motivation: a preliminary study of neural mechanisms. Eat Behav 2013; 14:447-50. [PMID: 24183133 PMCID: PMC3817498 DOI: 10.1016/j.eatbeh.2013.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/24/2013] [Accepted: 08/07/2013] [Indexed: 10/26/2022]
Abstract
Evening hyperphagia (EH; consumption of ≥25% of total daily calories after the evening meal) is a circadian delay in the pattern of daily food intake and is a core criterion of night eating syndrome (Allison et al., 2010). This preliminary study examined the brain response to food cues using functional magnetic resonance imaging (fMRI) in seven obese adults with EH compared to seven obese adults without EH. When contrasting food to non-food and blurry baseline images pre-meal, groups differed in brain activation in the inferior frontal gyrus, precentral gyrus, cingulate gyrus, superior temporal gyrus and cerebellum. At post meal, groups differed in brain activation in the fusiform gyrus, inferior frontal gyrus, inferior parietal lobule and the cerebellum. Significant interactions between time (pre-meal, post-meal) and group (EH, control) when contrasting food to non-food images were also noted in the inferior frontal gyrus and the superior temporal gyrus. Further research is necessary to replicate these findings and determine if they have a mechanistic role in the development of circadian delayed eating behavior in obese adults with EH.
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Affiliation(s)
- Jennifer D. Lundgren
- University of Missouri-Kansas City, Department of Psychology, 5030 Cherry Street, Kansas City, MO 64110, USA
| | - Trisha M. Patrician
- University of Kansas Medical Center, Center for Health Behavior Neuroscience, 3901 Rainbow Blvd, Kansas City, KS 66160, USA
| | - Florence Breslin
- University of Kansas Medical Center, Center for Health Behavior Neuroscience, 3901 Rainbow Blvd, Kansas City, KS 66160, USA
| | - Laura Martin
- University of Kansas Medical Center, Hoglund Brain Imaging Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Joseph E. Donnelly
- University of Kansas Medical Center, Center for Physical Activity and Weight Management, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Cary R. Savage
- University of Kansas Medical Center, Center for Health Behavior Neuroscience, 3901 Rainbow Blvd, Kansas City, KS 66160, USA
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Skibicka KP, Shirazi RH, Rabasa-Papio C, Alvarez-Crespo M, Neuber C, Vogel H, Dickson SL. Divergent circuitry underlying food reward and intake effects of ghrelin: dopaminergic VTA-accumbens projection mediates ghrelin's effect on food reward but not food intake. Neuropharmacology 2013; 73:274-83. [PMID: 23770258 DOI: 10.1016/j.neuropharm.2013.06.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/29/2013] [Accepted: 06/01/2013] [Indexed: 11/23/2022]
Abstract
Obesity has reached global epidemic proportions and creating an urgent need to understand mechanisms underlying excessive and uncontrolled food intake. Ghrelin, the only known circulating orexigenic hormone, potently increases food reward behavior. The neurochemical circuitry that links ghrelin to the mesolimbic reward system and to the increased food reward behavior remains unclear. Here we examine whether VTA-NAc dopaminergic signaling is required for the effects of ghrelin on food reward and intake. In addition, we examine the possibility of endogenous ghrelin acting on the VTA-NAc dopamine neurons. A D1-like or a D2 receptor antagonist was injected into the NAc in combination with ghrelin microinjection into the VTA to investigate whether this blockade attenuates ghrelin-induced food reward behavior. VTA injections of ghrelin produced a significant increase in food motivation/reward behavior, as measured by sucrose-induced progressive ratio operant conditioning, and chow intake. Pretreatment with either a D1-like or D2 receptor antagonist into the NAc, completely blocked the reward effect of ghrelin, leaving chow intake intact. We also found that this circuit is potentially relevant for the effects of endogenously released ghrelin as both antagonists reduced fasting (a state of high circulating levels of ghrelin) elevated sucrose-motivated behavior but not chow hyperphagia. Taken together our data identify the VTA to NAc dopaminergic projections, along with D1-like and D2 receptors in the NAc, as essential elements of the ghrelin responsive circuits controlling food reward behavior. Interestingly results also suggest that food reward behavior and simple intake of chow are controlled by divergent circuitry, where NAc dopamine plays an important role in food reward but not in food intake.
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