1
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Kumar M, Gusain C, Bhatt B, Lal R, Bishnoi M. Sex-specific effects of sucrose withdrawal on anxiety-like behavior and neuroimmune response. Neuropharmacology 2024; 249:109868. [PMID: 38403263 DOI: 10.1016/j.neuropharm.2024.109868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/13/2024] [Accepted: 02/09/2024] [Indexed: 02/27/2024]
Abstract
Sugar bingeing induces maladaptive neuroadaptations to decrease dietary control and promote withdrawal symptoms. This study investigated sex differences in sucrose bingeing, sucrose withdrawal-induced negative mood effects and underlying neuroimmune response in the prefrontal cortex (PFC) and nucleus accumbens (NAc) of C57BL/6J male and female mice. Two-bottle sucrose choice paradigm was used to develop sucrose dependence in mice. Female mice consumed more sucrose than male mice when given free access to water and 10% sucrose for four weeks. A significant increase in the mRNA expression of neuroinflammatory markers (Il1β, Tnfα) was found in the PFC of males exposed to sucrose withdrawal. Sucrose bingeing and subsequent sucrose withdrawal showed elevated protein levels of pro-inflammatory cytokines/chemokines/growth factors in the PFC (IL-1β, IL-6, TNFα, IFN-γ, IL-10, CCL5, VEGF) and NAc (IL-1β, IL-6, IL-10, VEGF) of male mice as compared to their water controls. These effects were concurrent with reduced mRNA expression of neuronal activation marker (cFos) in the PFC of sucrose withdrawal males. One week of sucrose withdrawal after prolonged sucrose consumption showed anxiety-like behavior in male mice, not in females. In conclusion, this study demonstrates that repeated access to sucrose induces anxiety-like behavior when the sugar is no longer available in the diet and these effects are male-specific. Elevated neuroinflammation in reward neurocircuitry may underlie these sex-specific effects.
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Affiliation(s)
- Mohit Kumar
- Centre for Excellence in Functional Foods, Food & Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, S.A.S Nagar, Sector 81 (Knowledge City), Punjab, India.
| | - Chitralekha Gusain
- Centre for Excellence in Functional Foods, Food & Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, S.A.S Nagar, Sector 81 (Knowledge City), Punjab, India
| | - Babita Bhatt
- Centre for Excellence in Functional Foods, Food & Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, S.A.S Nagar, Sector 81 (Knowledge City), Punjab, India
| | - Roshan Lal
- Centre for Excellence in Functional Foods, Food & Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, S.A.S Nagar, Sector 81 (Knowledge City), Punjab, India
| | - Mahendra Bishnoi
- Centre for Excellence in Functional Foods, Food & Nutrition Biotechnology Division, National Agri-Food Biotechnology Institute, S.A.S Nagar, Sector 81 (Knowledge City), Punjab, India
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2
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Senol E, Mohammad H. Current perspectives on brain circuits involved in food addiction-like behaviors. J Neural Transm (Vienna) 2024; 131:475-485. [PMID: 38216705 DOI: 10.1007/s00702-023-02732-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/17/2023] [Indexed: 01/14/2024]
Abstract
There is an emerging view that the increased availability of energy-dense foods in our society is contributing to excessive food consumption which could lead to food addiction-like behavior. Particularly, compulsive eating patterns are predominant in people suffering from eating disorders (binge-eating disorder, bulimia and anorexia nervosa) and obesity. Phenotypically, the behavioral pattern exhibits a close resemblance to individuals suffering from other forms of addiction (drug, sex, gambling). Growing body of evidence in neuroscience research is showing that excessive consumption of energy-dense foods alters the brain circuits implicated in reward, decision-making, control, habit formation, and emotions that are central to drug addiction. Here, we review the current understanding of the circuits of food addiction-like behaviors and highlight the future possibility of exploring those circuits to combat obesity and eating disorders.
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Affiliation(s)
- Esra Senol
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Hasan Mohammad
- Centre de Recherche en Biomédicine de Strasbourg (CRBS), L'Institut National de La Santé Et de La Recherche Médicale (Inserm) U1114, University of Strasbourg, Strasbourg, France.
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Punjab, 140306, India.
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3
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Sayar-Atasoy N, Yavuz Y, Laule C, Dong C, Kim H, Rysted J, Flippo K, Davis D, Aklan I, Yilmaz B, Tian L, Atasoy D. Opioidergic signaling contributes to food-mediated suppression of AgRP neurons. Cell Rep 2024; 43:113630. [PMID: 38165803 PMCID: PMC10865729 DOI: 10.1016/j.celrep.2023.113630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/22/2023] [Accepted: 12/13/2023] [Indexed: 01/04/2024] Open
Abstract
Opioids are generally known to promote hedonic food consumption. Although much of the existing evidence is primarily based on studies of the mesolimbic pathway, endogenous opioids and their receptors are widely expressed in hypothalamic appetite circuits as well; however, their role in homeostatic feeding remains unclear. Using a fluorescent opioid sensor, deltaLight, here we report that mediobasal hypothalamic opioid levels increase by feeding, which directly and indirectly inhibits agouti-related protein (AgRP)-expressing neurons through the μ-opioid receptor (MOR). AgRP-specific MOR expression increases by energy surfeit and contributes to opioid-induced suppression of appetite. Conversely, its antagonists diminish suppression of AgRP neuron activity by food and satiety hormones. Mice with AgRP neuron-specific ablation of MOR expression have increased fat preference without increased motivation. These results suggest that post-ingestion release of endogenous opioids contributes to AgRP neuron inhibition to shape food choice through MOR signaling.
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Affiliation(s)
- Nilufer Sayar-Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yavuz Yavuz
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Connor Laule
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Chunyang Dong
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Hyojin Kim
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jacob Rysted
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Kyle Flippo
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Debbie Davis
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Iltan Aklan
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Bayram Yilmaz
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Deniz Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center (FOEDRC), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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4
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Diaz JC, Dunaway K, Zuniga C, Sheil E, Sadeghian K, Auger AP, Baldo BA. Delayed estrogen actions diminish food consumption without changing food approach, motor activity, or hypothalamic activation elicited by corticostriatal µ-opioid signaling. Neuropsychopharmacology 2023; 48:1952-1962. [PMID: 37640922 PMCID: PMC10584984 DOI: 10.1038/s41386-023-01711-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 07/01/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
Mu-opioid receptor (μ-OR) signaling in forebrain sites including nucleus accumbens (Acb) and ventromedial prefrontal cortex (vmPFC) modulates reward-driven feeding and may play a role in the pathophysiology of disordered eating. In preclinical models, intra-Acb or intra-vmPFC μ-OR stimulation causes overeating and vigorous responding for food rewards. These effects have been studied mainly in male animals, despite demonstrated sex differences and estrogen modulation of central reward systems. Hence, the present study investigated sex differences and estrogen modulation of intra-Acb and intra-vmPFC μ-OR-driven feeding behaviors. First, the dose-related effects of intra-Acb and intra-vmPFC infusions of the μ-OR-selective agonist, DAMGO, were compared among intact female, ovariectomized (OVX) female, and intact male rats. The DAMGO feeding dose-effect function was flattened in intact females relative to the robust, dose-dependent effects observed in OVX females and intact males. Thus, in intact females, intra-Acb DAMGO failed to elevate food intake relative to vehicle, while intra-vmPFC DAMGO elevated food intake, but to a smaller degree compared to males and OVX females. Next, to explore the possible role of estrogen in mediating the diminished DAMGO response observed in intact females, OVX rats were given intra-Acb or intra-vmPFC infusions of DAMGO either immediately after a subcutaneous injection of 17-beta-estradiol 3-benzoate (EB; 5 μg/0.1 mL) or 24 h after EB injection. Intra-Acb DAMGO effects were not changed at the immediate post-EB time point. At the delayed post-EB timepoint, significant lordosis was noted and the duration of intra-Acb DAMGO-driven feeding bouts was significantly reduced, with no change in the number of bouts initiated, locomotor hyperactivity, or Fos immunoreactivity in hypothalamic feeding and arousal systems. Similarly, EB failed to alter the motor-activational effects of intra-vmPFC DAMGO while reducing feeding. These findings indicate that delayed, presumably genomically mediated estrogen actions modulate the μ-OR-generated motivational state by reducing consummatory activity while sparing goal-approach and general arousal/activity. The results additionally suggest that EB regulation of consummatory activity occurs outside of forebrain-μ-OR control of hypothalamic systems.
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Affiliation(s)
- Julio C Diaz
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | - Kate Dunaway
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
- College of Letters and Science, University of Wisconsin-Madison, Madison, WI, USA
| | - Carla Zuniga
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | - Elizabeth Sheil
- College of Letters and Science, University of Wisconsin-Madison, Madison, WI, USA
| | - Ken Sadeghian
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | - Anthony P Auger
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Department of Psychology, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian A Baldo
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA.
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5
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Rafferty G, Brar G, Petrut M, Meagher D, O'Connell H, St John-Smith P. Banging the drum: evolutionary and cultural origins of music and its implications for psychiatry. BJPsych Bull 2023; 47:251-254. [PMID: 37313980 PMCID: PMC10764840 DOI: 10.1192/bjb.2023.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 04/23/2023] [Indexed: 06/15/2023] Open
Abstract
SUMMARY There is growing interest in music-based therapies for mental/behavioural disorders. We begin by reviewing the evolutionary and cultural origins of music, proceeding then to discuss the principles of evolutionary psychiatry, itself a growing a field, and how it may apply to music. Finally we offer some implications for the role of music and music-based therapies in clinical practice.
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6
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Bini J. The historical progression of positron emission tomography research in neuroendocrinology. Front Neuroendocrinol 2023; 70:101081. [PMID: 37423505 PMCID: PMC10530506 DOI: 10.1016/j.yfrne.2023.101081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/29/2023] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
The rapid and continual development of a number of radiopharmaceuticals targeting different receptor, enzyme and small molecule systems has fostered Positron Emission Tomography (PET) imaging of endocrine system actions in vivo in the human brain for several decades. PET radioligands have been developed to measure changes that are regulated by hormone action (e.g., glucose metabolism, cerebral blood flow, dopamine receptors) and actions within endocrine organs or glands such as steroids (e.g., glucocorticoids receptors), hormones (e.g., estrogen, insulin), and enzymes (e.g., aromatase). This systematic review is targeted to the neuroendocrinology community that may be interested in learning about positron emission tomography (PET) imaging for use in their research. Covering neuroendocrine PET research over the past half century, researchers and clinicians will be able to answer the question of where future research may benefit from the strengths of PET imaging.
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Affiliation(s)
- Jason Bini
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States.
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7
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Iqbal A, Hamid A, Ahmad SM, Lutfy K. The Role of Mu Opioid Receptors in High Fat Diet-Induced Reward and Potentiation of the Rewarding Effect of Oxycodone. Life (Basel) 2023; 13:life13030619. [PMID: 36983775 PMCID: PMC10055773 DOI: 10.3390/life13030619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Excessive high fat diet (HFD) consumption can induce food addiction, which is believed to involve the communication between the hypothalamus and mesolimbic dopaminergic neurons, originating in the ventral tegmental area (VTA) and projecting to the nucleus accumbens (NAc). These brain areas are densely populated with opioid receptors, raising the possibility that these receptors, and particularly mu opioid receptors (MORs), are involved in rewards elicited by palatable food. This study sought to investigate the involvement of MORs in HFD-induced reward and if there is any difference between male and female subjects in this response. We also assessed if exposure to HFD would alter the rewarding action of oxycodone, a relatively selective MOR agonist. The place conditioning paradigm was used as an animal model of reward to determine if short-time (STC, 2 h) or long-time (LTC, 16 h) conditioning with HFD induces reward or alters the rewarding action of oxycodone. Male and female C57BL/6J mice as well as MOR knockout and their wildtype littermates of both sexes were tested for basal place preference on day 1 and then conditioned with an HFD in one chamber and a regular chow diet (RCD) in another chamber for 2 h on alternate days. Three sets of STC were used, followed by a set of LTC. Each set of conditioning consisted of two conditioning with RCD and two conditioning with HFD. Mice were tested for place preference after each set of STC and again after LTC. Controls were conditioned with RCD in both conditioning chambers. Following the last place preference test, mice were treated with oxycodone and conditioned in the HFD-paired chamber and with saline in the RCD-paired chamber for one hour once a day to explore the possibility if the HFD could alter oxycodone reward. The result showed that HFD induced conditioned place preference (CPP) in male but not female subjects. However, oxycodone conditioning elicited reward in both male and female mice of the HFD group but not the control group, showing that prior conditioning with HFD potentiated the rewarding action of oxycodone. The latter response was mediated via MORs, as it was blunted in MOR knockout mice. Similarly, HFD-induced CPP was blunted in male MOR knockout mice, suggesting sexual dimorphism in this response.
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8
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Sun L, Aarnio R, Herre EA, Kärnä S, Palani S, Virtanen H, Liljenbäck H, Virta J, Honkaniemi A, Oikonen V, Han C, Laurila S, Bucci M, Helin S, Yatkin E, Nummenmaa L, Nuutila P, Tang J, Roivainen A. [ 11C]carfentanil PET imaging for studying the peripheral opioid system in vivo: effect of photoperiod on mu-opioid receptor availability in brown adipose tissue. Eur J Nucl Med Mol Imaging 2023; 50:266-274. [PMID: 36166079 PMCID: PMC9816189 DOI: 10.1007/s00259-022-05969-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/15/2022] [Indexed: 01/11/2023]
Abstract
PURPOSE Photoperiod determines the metabolic activity of brown adipose tissue (BAT) and affects the food intake and body mass of mammals. Sympathetic innervation of the BAT controls thermogenesis and facilitates physiological adaption to seasonal changes, but the exact mechanism remains elusive. Previous studies have shown that central opioid signaling regulates BAT thermogenesis, and that the expression of the brain mu-opioid receptor (MOR) varies seasonally. Therefore, it is important to know whether MOR expression in BAT shows seasonal variation. METHODS We determined the effect of photoperiod on BAT MOR availability using [11C]carfentanil positron emission tomography (PET). Adult rats (n = 9) were repeatedly imaged under various photoperiods in order to simulate seasonal changes. RESULTS Long photoperiod was associated with low MOR expression in BAT (β = - 0.04, 95% confidence interval: - 0.07, - 0.01), but not in muscles. We confirmed the expression of MOR in BAT and muscle using immunofluorescence staining. CONCLUSION Photoperiod affects MOR availability in BAT. Sympathetic innervation of BAT may influence thermogenesis via the peripheral MOR system. The present study supports the utility of [11C]carfentanil PET to study the peripheral MOR system.
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Affiliation(s)
- Lihua Sun
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China.
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland.
| | - Richard Aarnio
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Erika Atencio Herre
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Salli Kärnä
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Senthil Palani
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Helena Virtanen
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Heidi Liljenbäck
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Turku Center for Disease Modeling, University of Turku, 20520, Turku, Finland
| | - Jenni Virta
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Aake Honkaniemi
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Vesa Oikonen
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Chunlei Han
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Sanna Laurila
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Heart Center, Turku University Hospital, 20520, Turku, Finland
| | - Marco Bucci
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, 17177, Stockholm, Sweden
- Theme Inflammation and Aging, Karolinska University Hospital, 14186, Stockholm, Sweden
- Turku PET Centre, Åbo Akademi University, Turku, Finland
| | - Semi Helin
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Emrah Yatkin
- Central Animal Laboratory, University of Turku, 20520, Turku, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Department of Psychology, University of Turku, 20520, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Department of Endocrinology, Turku University Hospital, 20520, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, 20520, Turku, Finland
| | - Jing Tang
- Research Program in Systems Oncology, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Anne Roivainen
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
- Turku Center for Disease Modeling, University of Turku, 20520, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, 20520, Turku, Finland
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9
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Spatial quantification of single cell mRNA and ligand binding of the kappa opioid receptor in the rat hypothalamus. J Chem Neuroanat 2023; 127:102205. [PMID: 36464066 DOI: 10.1016/j.jchemneu.2022.102205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/18/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022]
Abstract
Detailed quantification of brain tissue provides a deeper understanding of changes in expression and function. We have created a pipeline to study the detailed expression patterns of the kappa opioid receptor in the rat hypothalamus using high resolution fluorescence microscopy and receptor autoradiography. The workflow involved structured serial sampling of rat hypothalamic nuclei, in situ detection of mRNA and receptor expression, and advanced image analysis. Our results demonstrate how maintaining spatial information can lead to increased understanding of RNA and protein expression. In addition, we show the detailed expression patterns of the kappa opioid receptor in the rat hypothalamus.
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10
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Bzdok D, Dunbar RIM. Social isolation and the brain in the pandemic era. Nat Hum Behav 2022; 6:1333-1343. [PMID: 36258130 DOI: 10.1038/s41562-022-01453-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 08/24/2022] [Indexed: 11/08/2022]
Abstract
Intense sociality has been a catalyst for human culture and civilization, and our social relationships at a personal level play a pivotal role in our health and well-being. These relationships are, however, sensitive to the time we invest in them. To understand how and why this should be, we first outline the evolutionary background in primate sociality from which our human social world has emerged. We then review defining features of that human sociality, putting forward a framework within which one can understand the consequences of mass social isolation during the COVID-19 pandemic, including mental health deterioration, stress, sleep disturbance and substance misuse. We outline recent research on the neural basis of prolonged social isolation, highlighting especially higher-order neural circuits such as the default mode network. Our survey of studies covers the negative effects of prolonged social deprivation and the multifaceted drivers of day-to-day pandemic experiences.
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Affiliation(s)
- Danilo Bzdok
- The Neuro-Montreal Neurological Institute (MNI), McConnell Brain-Imaging Centre (BIC), Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
| | - Robin I M Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford, UK.
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11
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Joshi A, Schott M, la Fleur SE, Barrot M. Role of the striatal dopamine, GABA and opioid systems in mediating feeding and fat intake. Neurosci Biobehav Rev 2022; 139:104726. [PMID: 35691472 DOI: 10.1016/j.neubiorev.2022.104726] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 12/08/2021] [Accepted: 06/05/2022] [Indexed: 10/18/2022]
Abstract
Food intake, which is a highly reinforcing behavior, provides nutrients required for survival in all animals. However, when fat and sugar consumption goes beyond the daily needs, it can favor obesity. The prevalence and severity of this health problem has been increasing with time. Besides covering nutrient and energy needs, food and in particular its highly palatable components, such as fats, also induce feelings of joy and pleasure. Experimental evidence supports a role of the striatal complex and of the mesolimbic dopamine system in both feeding and food-related reward processing, with the nucleus accumbens as a key target for reward or reinforcing-associated signaling during food intake behavior. In this review, we provide insights concerning the impact of feeding, including fat intake, on different types of receptors and neurotransmitters present in the striatal complex. Reciprocally, we also cover the evidence for a modulation of palatable food intake by different neurochemical systems in the striatal complex and in particular the nucleus accumbens, with a focus on dopamine, GABA and the opioid system.
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Affiliation(s)
- Anil Joshi
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France; Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands
| | - Marion Schott
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Susanne Eva la Fleur
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands.
| | - Michel Barrot
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
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12
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Brouns F, Shewry PR. Do gluten peptides stimulate weight gain in humans? NUTR BULL 2022; 47:186-198. [PMID: 35915782 PMCID: PMC9328276 DOI: 10.1111/nbu.12558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/05/2022] [Accepted: 04/19/2022] [Indexed: 02/06/2023]
Abstract
Observations from animal and in vitro laboratory research, and anecdotal evidence, have led to the suggestion that gluten consumption stimulates weight gain by the presence of peptides expressing opioid activity. Another proposed mechanism is that gluten peptides decrease resting energy expenditure resulting in a positive energy balance. In order to induce such effects in vivo, intact food peptides must be absorbed in sufficient quantities, remain intact in the blood for sufficient time to have long‐lasting biological activity and bind to receptors involved in appetite, satiety and energy regulation. However, although peptides from food may pass from the intestine into the blood in extremely low quantities, they are generally rapidly degraded by plasma and vasculum‐bound aminopeptidases, resulting in very short half‐lives and loss of bioactivity. At present, gluten peptide sequences that influence regulators of energy metabolism have not been identified. Furthermore, data on the quantitative absorption of gluten peptides in the blood stream, their stability and lasting bioactivity are also lacking. Therefore, there is no evidence for proposed effects on driving appetite by the brain, nor on energy expenditure and weight gain. Furthermore, the level of overweight observed in various countries appears to be independent of the level of wheat consumption, and abundant observational evidence in humans shows that the levels of gluten consumption are neither related to daily calorie intake nor to BMI. This narrative review therefore discusses the proposed effects of gluten on bodyweight (BW) and putative biological mechanisms in the light of the current evidence.
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Affiliation(s)
- Fred Brouns
- School for Nutrition and Translational Research in Metabolism Maastricht University Maastricht The Netherlands
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Lee GJ, Kim YJ, Shim SW, Lee K, Oh SB. Anterior insular-nucleus accumbens pathway controls refeeding-induced analgesia under chronic inflammatory pain condition. Neuroscience 2022; 495:58-73. [DOI: 10.1016/j.neuroscience.2022.05.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/21/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
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μ-opioid receptor availability is associated with sex drive in human males. COGNITIVE, AFFECTIVE, & BEHAVIORAL NEUROSCIENCE 2022; 22:281-290. [PMID: 34811707 PMCID: PMC8983533 DOI: 10.3758/s13415-021-00960-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/04/2022]
Abstract
The endogenous mu-opioid receptor (MOR) system modulates a multitude of social and reward-related functions, and exogenous opiates also influence sex drive in humans and animals. Sex drive shows substantial variation across humans, and it is possible that individual differences in MOR availability underlie interindividual of variation in human sex drive. We measured healthy male subjects’ (n = 52) brain’s MOR availability with positron emission tomography (PET) using an agonist radioligand, [11C]carfentanil, that has high affinity for MORs. Sex drive was measured using self-reports of engaging in sexual behaviour (sex with partner and masturbating). Bayesian hierarchical regression analysis revealed that sex drive was positively associated with MOR availability in cortical and subcortical areas, notably in caudate nucleus, hippocampus, and cingulate cortices. These results were replicated in full-volume GLM analysis. These widespread effects are in line with high spatial autocorrelation in MOR expression in human brain. Complementary voxel-based morphometry analysis (n = 108) of anatomical MR images provided limited evidence for positive association between sex drive and cortical density in the midcingulate cortex. We conclude that endogenous MOR tone is associated with individual differences in sex drive in human males.
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Obesity risk is associated with altered cerebral glucose metabolism and decreased μ-opioid and CB 1 receptor availability. Int J Obes (Lond) 2021; 46:400-407. [PMID: 34728775 PMCID: PMC8794779 DOI: 10.1038/s41366-021-00996-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 07/06/2021] [Accepted: 10/12/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Obesity is a pressing public health concern worldwide. Novel pharmacological means are urgently needed to combat the increase of obesity and accompanying type 2 diabetes (T2D). Although fully established obesity is associated with neuromolecular alterations and insulin resistance in the brain, potential obesity-promoting mechanisms in the central nervous system have remained elusive. In this triple-tracer positron emission tomography study, we investigated whether brain insulin signaling, μ-opioid receptors (MORs) and cannabinoid CB1 receptors (CB1Rs) are associated with risk for developing obesity. METHODS Subjects were 41 young non-obese males with variable obesity risk profiles. Obesity risk was assessed by subjects' physical exercise habits, body mass index and familial risk factors, including parental obesity and T2D. Brain glucose uptake was quantified with [18F]FDG during hyperinsulinemic euglycemic clamp, MORs were quantified with [11C]carfentanil and CB1Rs with [18F]FMPEP-d2. RESULTS Subjects with higher obesity risk had globally increased insulin-stimulated brain glucose uptake (19 high-risk subjects versus 19 low-risk subjects), and familial obesity risk factors were associated with increased brain glucose uptake (38 subjects) but decreased availability of MORs (41 subjects) and CB1Rs (36 subjects). CONCLUSIONS These results suggest that the hereditary mechanisms promoting obesity may be partly mediated via insulin, opioid and endocannabinoid messaging systems in the brain.
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Giacomini JL, Geiduschek E, Selleck RA, Sadeghian K, Baldo BA. Dissociable control of μ-opioid-driven hyperphagia vs. food impulsivity across subregions of medial prefrontal, orbitofrontal, and insular cortex. Neuropsychopharmacology 2021; 46:1981-1989. [PMID: 34226656 PMCID: PMC8429588 DOI: 10.1038/s41386-021-01068-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/29/2021] [Accepted: 06/08/2021] [Indexed: 12/31/2022]
Abstract
This study explored potentially dissociable functions of mu-opioid receptor (µ-OR) signaling across different cortical territories in the control of anticipatory activity directed toward palatable food, consumption, and impulsive food-seeking behavior in male rats. The µ-OR agonist, DAMGO ([D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin), was infused into infralimbic cortex (ILC), prelimbic cortex (PrL), medial and lateral ventral orbitofrontal cortices (VMO, VLO), and agranular/dysgranular insular (AI/DI) cortex of rats. Intra-ILC DAMGO markedly enhanced contact with a see-through screen behind which sucrose pellets were sequestered; in addition, rats having received intra-ILC and intra-VMO DAMGO exhibited locomotor hyperactivity while the screen was in place. Upon screen removal, intra-ILC and -VMO-treated rats emitted numerous, brief sucrose-intake bouts (yielding increased overall intake) interspersed with significant hyperactivity. In contrast, intra-AI/DI-treated rats consumed large amounts of sucrose in long, uninterrupted bouts with no anticipatory hyperactivity pre-screen removal. Intra-PrL and intra-VLO DAMGO altered neither pre-screen behavior nor sucrose intake. Finally, all rats were tested in a sucrose-reinforced differential reinforcement of low rates (DRL) task, which assesses the ability to advantageously withhold premature responses. DAMGO affected (impaired) DRL performance when infused into ILC only. These site-based dissociations reveal differential control of µ-OR-modulated appetitive/approach vs. consummatory behaviors by ventromedial/orbitofrontal and insular networks, respectively, and suggest a unique role of ILC µ-ORs in modulating inhibitory control.
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Affiliation(s)
- Juliana L. Giacomini
- grid.14003.360000 0001 2167 3675Graduate Program in Cellular and Molecular Biology, Physiology Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Emma Geiduschek
- grid.14003.360000 0001 2167 3675Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Ryan A. Selleck
- grid.252000.50000 0001 0728 549XDepartment of Psychological Science, Albion College, Albion, MI USA
| | - Ken Sadeghian
- grid.14003.360000 0001 2167 3675Department of Psychiatry, University of Wisconsin-Madison, Madison, WI USA
| | - Brian A. Baldo
- grid.14003.360000 0001 2167 3675Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Department of Psychiatry, University of Wisconsin-Madison, Madison, WI USA
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Kantonen T, Karjalainen T, Pekkarinen L, Isojärvi J, Kalliokoski K, Kaasinen V, Hirvonen J, Nuutila P, Nummenmaa L. Cerebral μ-opioid and CB 1 receptor systems have distinct roles in human feeding behavior. Transl Psychiatry 2021; 11:442. [PMID: 34453034 PMCID: PMC8397789 DOI: 10.1038/s41398-021-01559-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 12/13/2022] Open
Abstract
Eating behavior varies greatly between individuals, but the neurobiological basis of these trait-like differences in feeding remains poorly understood. Central μ-opioid receptors (MOR) and cannabinoid CB1 receptors (CB1R) regulate energy balance via multiple neural pathways, promoting food intake and reward. Because obesity and eating disorders have been associated with alterations in the brain's opioid and endocannabinoid signaling, the variation in MOR and CB1R system function could potentially underlie distinct eating behavior phenotypes. In this retrospective positron emission tomography (PET) study, we analyzed [11C]carfentanil PET scans of MORs from 92 healthy subjects (70 males and 22 females), and [18F]FMPEP-d2 scans of CB1Rs from 35 subjects (all males, all also included in the [11C]carfentanil sample). Eating styles were measured with the Dutch Eating Behavior Questionnaire (DEBQ). We found that lower cerebral MOR availability was associated with increased external eating-individuals with low MORs reported being more likely to eat in response to environment's palatable food cues. CB1R availability was associated with multiple eating behavior traits. We conclude that although MORs and CB1Rs overlap anatomically in brain regions regulating food reward, they have distinct roles in mediating individual feeding patterns. Central MOR system might provide a pharmacological target for reducing individual's excessive cue-reactive eating behavior.
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Affiliation(s)
- Tatu Kantonen
- Turku PET Centre, University of Turku, Turku, Finland. .,Clinical Neurosciences, University of Turku, Turku, Finland.
| | - Tomi Karjalainen
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland
| | - Laura Pekkarinen
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland ,grid.410552.70000 0004 0628 215XDepartment of Endocrinology, Turku University Hospital, Turku, Finland
| | - Janne Isojärvi
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland
| | - Kari Kalliokoski
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland
| | - Valtteri Kaasinen
- grid.1374.10000 0001 2097 1371Clinical Neurosciences, University of Turku, Turku, Finland ,grid.410552.70000 0004 0628 215XNeurocenter, Turku University Hospital, Turku, Finland
| | - Jussi Hirvonen
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland ,grid.1374.10000 0001 2097 1371Department of Radiology, University of Turku and Turku University Hospital, Turku, Finland
| | - Pirjo Nuutila
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland ,grid.410552.70000 0004 0628 215XDepartment of Endocrinology, Turku University Hospital, Turku, Finland
| | - Lauri Nummenmaa
- grid.470895.70000 0004 0391 4481Turku PET Centre, University of Turku, Turku, Finland ,grid.1374.10000 0001 2097 1371Department of Psychology, University of Turku, Turku, Finland
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Dunbar RIM, Frangou A, Grainger F, Pearce E. Laughter influences social bonding but not prosocial generosity to friends and strangers. PLoS One 2021; 16:e0256229. [PMID: 34388212 PMCID: PMC8362988 DOI: 10.1371/journal.pone.0256229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/03/2021] [Indexed: 12/30/2022] Open
Abstract
Humans deploy a number of specific behaviours for forming social bonds, one of which is laughter. However, two questions have not yet been investigated with respect to laughter: (1) Does laughter increase the sense of bonding to those with whom we laugh? and (2) Does laughter facilitate prosocial generosity? Using changes in pain threshold as a proxy for endorphin upregulation in the brain and a standard economic game (the Dictator Game) as an assay of prosociality, we show that laughter does trigger the endorphin system and, through that, seems to enhance social bonding, but it does not reliably influence donations to others. This suggests that social bonding and prosociality may operate via different mechanisms, or on different time scales, and relate to different functional objectives.
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Affiliation(s)
- R. I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Anna Frangou
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Felix Grainger
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Eiluned Pearce
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University College London, London, United Kingdom
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Ciria LF, Watson P, Vadillo MA, Luque D. Is the habit system altered in individuals with obesity? A systematic review. Neurosci Biobehav Rev 2021; 128:621-632. [PMID: 34252472 DOI: 10.1016/j.neubiorev.2021.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/27/2021] [Accepted: 07/06/2021] [Indexed: 12/15/2022]
Abstract
Habit-like eating behavior is repeatedly pointed to as a key cognitive mechanism contributing to the emergence and maintenance of obesity. Here, we conducted a systematic review of the literature to assess the existent behavioral evidence for the Habit Hypothesis for Overeating (HHO) which states that obesity is the consequence of an imbalance between the habit and goal-directed reward learning systems, leading to overconsumption of food. We found a total of 19 studies implementing a variety of experimental protocols (i.e., free operant paradigm, slips-of-action test, two-step task, Pavlovian-to-Instrumental paradigm, probabilistic learning task) and manipulations. Taken together, the studies on clinical (binge eating disorder) and non-clinical individuals with overweight or obesity do not support the HHO conclusively. While the scientific literature on HHO is still in its infancy, the heterogeneity of the extant studies makes it difficult to evaluate the degree of convergence of these findings. Uncovering the role of reward learning systems in eating behaviors might have a transformative impact on public health.
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Affiliation(s)
- Luis F Ciria
- Departamento de Psicología Básica, Universidad Autónoma de Madrid, Spain; Departamento de Psicología Básica, Universidad de Málaga, Spain.
| | - Poppy Watson
- School of Psychology, University of New South Wales, Sydney, Australia
| | - Miguel A Vadillo
- Departamento de Psicología Básica, Universidad Autónoma de Madrid, Spain
| | - David Luque
- Departamento de Psicología Básica, Universidad Autónoma de Madrid, Spain; Departamento de Psicología Básica, Universidad de Málaga, Spain.
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Karlsson HK, Tuominen L, Helin S, Salminen P, Nuutila P, Nummenmaa L. Preoperative brain μ-opioid receptor availability predicts weight development following bariatric surgery in women. JCI Insight 2021; 6:147820. [PMID: 33848266 PMCID: PMC8262287 DOI: 10.1172/jci.insight.147820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/07/2021] [Indexed: 01/15/2023] Open
Abstract
Bariatric surgery is the most effective method for weight loss in morbid obesity. There is significant individual variability in the weight loss outcomes, yet factors leading to postoperative weight loss or weight regain remain elusive. Alterations in the μ-opioid receptor (MOR) and dopamine D2 receptor (D2R) systems are associated with obesity and appetite control, and the magnitude of initial brain receptor system perturbation may predict long-term surgical weight loss outcomes. We tested this hypothesis by studying 19 morbidly obese women (mean BMI 40) scheduled to undergo bariatric surgery. We measured their preoperative MOR and D2R availabilities using positron emission tomography with [11C]carfentanil and [11C]raclopride, respectively, and then assessed their weight development association with regional MOR and D2R availabilities at 24-month follow-up. MOR availability in the amygdala consistently predicted weight development throughout the follow-up period, but no associations were found for D2R. This is the first study to our knowledge to demonstrate that neuroreceptor markers prior to bariatric surgery are associated with postoperative weight development. Postoperative weight regain may derive from dysfunction in the opioid system, and weight loss outcomes after bariatric surgery may be partially predicted based on preoperative brain receptor availability, opening up new potential for treatment possibilities.
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Affiliation(s)
- Henry K Karlsson
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Lauri Tuominen
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland.,Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
| | - Semi Helin
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Paulina Salminen
- Division of Digestive Surgery and Urology, Turku University Hospital, Turku, Finland.,Department of Surgery, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland.,Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland.,Department of Psychology, University of Turku, Turku, Finland
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Ashok AH, Myers J, Frost G, Turton S, Gunn RN, Passchier J, Colasanti A, Marques TR, Nutt D, Lingford-Hughes A, Howes OD, Rabiner EA. Acute acetate administration increases endogenous opioid levels in the human brain: A [ 11C]carfentanil molecular imaging study. J Psychopharmacol 2021; 35:606-610. [PMID: 33406950 PMCID: PMC8155733 DOI: 10.1177/0269881120965912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION A recent study has shown that acetate administration leads to a fourfold increase in the transcription of proopiomelanocortin (POMC) mRNA in the hypothalamus. POMC is cleaved to peptides, including β-endorphin, an endogenous opioid (EO) agonist that binds preferentially to the µ-opioid receptor (MOR). We hypothesised that an acetate challenge would increase the levels of EO in the human brain. We have previously demonstrated that increased EO release in the human brain can be detected using positron emission tomography (PET) with the selective MOR radioligand [11C]carfentanil. We used this approach to evaluate the effects of an acute acetate challenge on EO levels in the brain of healthy human volunteers. METHODS Seven volunteers each completed a baseline [11C]carfentanil PET scan followed by an administration of sodium acetate before a second [11C]carfentanil PET scan. Dynamic PET data were acquired over 90 minutes, and corrected for attenuation, scatter and subject motion. Regional [11C] carfentanil BPND values were then calculated using the simplified reference tissue model (with the occipital grey matter as the reference region). Change in regional EO concentration was evaluated as the change in [11C]carfentanil BPND following acetate administration. RESULTS Following sodium acetate administration, 2.5-6.5% reductions in [11C]carfentanil regional BPND were seen, with statistical significance reached in the cerebellum, temporal lobe, orbitofrontal cortex, striatum and thalamus. CONCLUSIONS We have demonstrated that an acute acetate challenge has the potential to increase EO release in the human brain, providing a plausible mechanism of the central effects of acetate on appetite in humans.
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Affiliation(s)
- Abhishekh H Ashok
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences (LMS), Imperial College London, London, UK.,Psychiatric Imaging Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Department of Radiology, University of Cambridge, Cambridge, UK.,Department of Radiology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | | | | | - Samuel Turton
- Imperial College London, UK.,Institute of Psychiatry, Psychology and Neurosciences, King's College London, London, UK
| | - Roger N Gunn
- Imperial College London, UK.,Invicro, London, UK
| | | | - Alessandro Colasanti
- Department of Neuroscience, Brighton and Sussex Medical School, University of Sussex, Brighton, UK
| | - Tiago Reis Marques
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences (LMS), Imperial College London, London, UK.,Psychiatric Imaging Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | | | | | - Oliver D Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences (LMS), Imperial College London, London, UK.,Psychiatric Imaging Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Eugenii A Rabiner
- Institute of Psychiatry, Psychology and Neurosciences, King's College London, London, UK.,Invicro, London, UK
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Meier IM, Eikemo M, Leknes S. The Role of Mu-Opioids for Reward and Threat Processing in Humans: Bridging the Gap from Preclinical to Clinical Opioid Drug Studies. CURRENT ADDICTION REPORTS 2021; 8:306-318. [PMID: 34722114 PMCID: PMC8550464 DOI: 10.1007/s40429-021-00366-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2021] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW Opioid receptors are widely expressed in the human brain. A number of features commonly associated with drug use disorder, such as difficulties in emotional learning, emotion regulation and anhedonia, have been linked to endogenous opioid signalling. Whereas chronic substance use and misuse are thought to alter the function of the mu-opioid system, the specific mechanisms are not well understood. We argue that understanding exogenous and endogenous opioid effects in the healthy human brain is an essential foundation for bridging preclinical and clinical findings related to opioid misuse. Here, we will examine psychopharmacological evidence to outline the role of the mu-opioid receptor (MOR) system in the processing of threat and reward, and discuss how disruption of these processes by chronic opioid use might alter emotional learning and reward responsiveness. RECENT FINDINGS In healthy people, studies using opioid antagonist drugs indicate that the brain's endogenous opioids downregulate fear reactivity and upregulate learning from safety. At the same time, endogenous opioids increase the liking of and motivation to engage with high reward value cues. Studies of acute opioid agonist effects indicate that with non-sedative doses, drugs such as morphine and buprenorphine can mimic endogenous opioid effects on liking and wanting. Disruption of endogenous opioid signalling due to prolonged opioid exposure is associated with some degree of anhedonia to non-drug rewards; however, new results leave open the possibility that this is not directly opioid-mediated. SUMMARY The available human psychopharmacological evidence indicates that the healthy mu-opioid system contributes to the regulation of reward and threat processing. Overall, endogenous opioids can subtly increase liking and wanting responses to a wide variety of rewards, from sweet tastes to feelings of being connected to close others. For threat-related processing, human evidence suggests that endogenous opioids inhibit fear conditioning and reduce the sensitivity to aversive stimuli, although inconsistencies remain. The size of effects reported in healthy humans are however modest, clearly indicating that MORs play out their role in close concert with other neurotransmitter systems. Relevant candidate systems for future research include dopamine, serotonin and endocannabinoid signalling. Nevertheless, it is possible that endogenous opioid fine-tuning of reward and threat processing, when unbalanced by e.g. opioid misuse, could over time develop into symptoms associated with opioid use disorder, such as anhedonia and depression/anxiety.
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Affiliation(s)
- Isabell M. Meier
- Department of Diagnostic Physics, Oslo University Hospital, Sognsvannsveien 20, 0372 Oslo, Norway
| | - Marie Eikemo
- Department of Psychology, University of Oslo, Blindern, 0317 Oslo, Norway
| | - Siri Leknes
- Department of Diagnostic Physics, Oslo University Hospital, Sognsvannsveien 20, 0372 Oslo, Norway
- Department of Psychology, University of Oslo, Blindern, 0317 Oslo, Norway
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Seasonal Variation in the Brain μ-Opioid Receptor Availability. J Neurosci 2021; 41:1265-1273. [PMID: 33361461 PMCID: PMC7888218 DOI: 10.1523/jneurosci.2380-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/19/2020] [Accepted: 12/07/2020] [Indexed: 02/08/2023] Open
Abstract
Seasonal rhythms influence mood and sociability. The brain μ-opioid receptor (MOR) system modulates a multitude of seasonally varying socioemotional functions, but its seasonal variation remains elusive with no previously reported in vivo evidence. Here, we first conducted a cross-sectional study with previously acquired human [11C]carfentanil PET imaging data (132 male and 72 female healthy subjects) to test whether there is seasonal variation in MOR availability. We then investigated experimentally whether seasonal variation in daylength causally influences brain MOR availability in rats. Rats (six male and three female rats) underwent daylength cycle simulating seasonal changes; control animals (two male and one female rats) were kept under constant daylength. Animals were scanned repeatedly with [11C]carfentanil PET imaging. Seasonally varying daylength had an inverted U-shaped functional relationship with brain MOR availability in humans. Brain regions sensitive to daylength spanned the socioemotional brain circuits, where MOR availability peaked during spring. In rats, MOR availabilities in the brain neocortex, thalamus, and striatum peaked at intermediate daylength. Varying daylength also affected the weight gain and stress hormone levels. We conclude that cerebral MOR availability in humans and rats shows significant seasonal variation, which is predominately associated with seasonal photoperiodic variation. Given the intimate links between MOR signaling and socioemotional behavior, these results suggest that the MOR system might underlie seasonal variation in human mood and social behavior.SIGNIFICANCE STATEMENT Seasonal rhythms influence emotion and sociability. The central μ-opioid receptor (MOR) system modulates numerous seasonally varying socioemotional functions, but its seasonal variation remains elusive. Here we used positron emission tomography to show that MOR levels in both human and rat brains show daylength-dependent seasonal variation. The highest MOR availability was observed at intermediate daylengths. Given the intimate links between MOR signaling and socioemotional behavior, these results suggest that the MOR system might underlie seasonal variation in human mood and social behavior.
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Nummenmaa L, Karjalainen T, Isojärvi J, Kantonen T, Tuisku J, Kaasinen V, Joutsa J, Nuutila P, Kalliokoski K, Hirvonen J, Hietala J, Rinne J. Lowered endogenous mu-opioid receptor availability in subclinical depression and anxiety. Neuropsychopharmacology 2020; 45:1953-1959. [PMID: 32473595 PMCID: PMC7608336 DOI: 10.1038/s41386-020-0725-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/08/2020] [Accepted: 05/22/2020] [Indexed: 11/09/2022]
Abstract
Major depressive disorder is associated with lowered mood, anxiety, anhedonia, sleep problems, and cognitive impairments. Many of these functions are regulated by μ-opioid receptor (MOR) system. Preclinical, in vivo, and post-mortem studies have however yielded inconclusive results regarding the role of the MOR in depression and anxiety. Moreover, it is not known whether alterations in MOR are already present in subclinical depression and anxiety. In a large-scale retrospective cross-sectional study we pooled data from 135 (113 males and 22 females) healthy subjects whose brain's MOR availability was measured with positron emission tomography (PET) using an agonist radioligand [11C]carfentanil that has high affinity for MORs. Depressive and anxious symptomology was addressed with BDI-II and STAI-X questionnaires, respectively. Both anxiety and depression scores in the subclinical range were negatively associated with MOR availability in cortical and subcortical areas, notably in amygdala, hippocampus, ventral striatum, and orbitofrontal and cingulate cortices. We conclude that dysregulated MOR availability is involved in altered mood and pathophysiology of depression and anxiety disorders.
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Affiliation(s)
- Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland.
- Department of Psychology, University of Turku, Turku, Finland.
- Turku University Hospital University of Turku, Turku, Finland.
| | | | | | - Tatu Kantonen
- Turku PET Centre, University of Turku, Turku, Finland
- Clinical Neurosciences, University of Turku and Turku University Hospital, Turku, Finland
| | - Jouni Tuisku
- Turku PET Centre, University of Turku, Turku, Finland
| | - Valtteri Kaasinen
- Turku PET Centre, University of Turku, Turku, Finland
- Clinical Neurosciences, University of Turku and Turku University Hospital, Turku, Finland
| | - Juho Joutsa
- Turku PET Centre, University of Turku, Turku, Finland
- Clinical Neurosciences, University of Turku and Turku University Hospital, Turku, Finland
- Turku Brain and Mind Center, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
| | | | - Jussi Hirvonen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Radiology, Turku University Hospital, Turku, Finland
| | - Jarmo Hietala
- Turku University Hospital University of Turku, Turku, Finland
- Department of Psychiatry, University of Turku and Turku University Hospital, Turku, Finland
| | - Juha Rinne
- Turku PET Centre, University of Turku, Turku, Finland
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28
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Turton S, Myers JF, Mick I, Colasanti A, Venkataraman A, Durant C, Waldman A, Brailsford A, Parkin MC, Dawe G, Rabiner EA, Gunn RN, Lightman SL, Nutt DJ, Lingford-Hughes A. Blunted endogenous opioid release following an oral dexamphetamine challenge in abstinent alcohol-dependent individuals. Mol Psychiatry 2020; 25:1749-1758. [PMID: 29942043 PMCID: PMC6169731 DOI: 10.1038/s41380-018-0107-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 05/09/2018] [Accepted: 05/14/2018] [Indexed: 01/12/2023]
Abstract
Addiction has been proposed as a 'reward deficient' state, which is compensated for with substance use. There is growing evidence of dysregulation in the opioid system, which plays a key role in reward, underpinning addiction. Low levels of endogenous opioids are implicated in vulnerability for developing alcohol dependence (AD) and high mu-opioid receptor (MOR) availability in early abstinence is associated with greater craving. This high MOR availability is proposed to be the target of opioid antagonist medication to prevent relapse. However, changes in endogenous opioid tone in AD are poorly characterised and are important to understand as opioid antagonists do not help everyone with AD. We used [11C]carfentanil, a selective MOR agonist positron emission tomography (PET) radioligand, to investigate endogenous opioid tone in AD for the first time. We recruited 13 abstinent male AD and 15 control participants who underwent two [11C]carfentanil PET scans, one before and one 3 h following a 0.5 mg/kg oral dose of dexamphetamine to measure baseline MOR availability and endogenous opioid release. We found significantly blunted dexamphetamine-induced opioid release in 5 out of 10 regions-of-interest including insula, frontal lobe and putamen in AD compared with controls, but no significantly higher MOR availability AD participants compared with HC in any region. This study is comparable to our previous results of blunted dexamphetamine-induced opioid release in gambling disorder, suggesting that this dysregulation in opioid tone is common to both behavioural and substance addictions.
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Affiliation(s)
- Samuel Turton
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
| | - James Fm Myers
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
| | - Inge Mick
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
- Institute for Clinical Teratology and Drug Risk Assessment in Pregnancy, Charité Universitätsmedizin, Berlin, Germany
| | - Alessandro Colasanti
- Department of Neuroscience, Brighton and Sussex Medical School, University of Sussex, Brighton, UK
- Centre for Affective Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Ashwin Venkataraman
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
| | - Claire Durant
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
| | - Adam Waldman
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Alan Brailsford
- Analytical and Environmental Sciences, King's College London, London, UK
| | - Mark C Parkin
- Analytical and Environmental Sciences, King's College London, London, UK
| | - Gemma Dawe
- Department of Neuroradiology, Imperial College Healthcare NHS Trust, London, UK
| | - Eugenii A Rabiner
- Imanova Limited, London, UK
- Centre for Neuroimaging Sciences, King's College London, London, UK
| | - Roger N Gunn
- Imanova Limited, London, UK
- Centre for Restorative Neuroscience, Division of Brain Sciences, Imperial College London, London, UK
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience & Endocrinology, University of Bristol, Bristol, UK
| | - David J Nutt
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK
| | - Anne Lingford-Hughes
- Neuropsychopharmacology Unit, Centre for Psychiatry, Imperial College London, London, UK.
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29
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Abstract
This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY, 11367, United States.
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30
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Løseth GE, Eikemo M, Leknes S. Effects of opioid receptor stimulation and blockade on touch pleasantness: a double-blind randomised trial. Soc Cogn Affect Neurosci 2020; 14:411-422. [PMID: 30951167 PMCID: PMC6523440 DOI: 10.1093/scan/nsz022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/21/2019] [Accepted: 03/23/2019] [Indexed: 11/23/2022] Open
Abstract
The μ-opioid receptor (MOR) system has long been thought to underpin the rewarding properties of pleasant touch. Numerous non-human animal studies implicate MORs in social behaviours involving touch, but little is currently known about MOR involvement in human touch reward. Here, we employed a bi-directional pharmacological double-blind crossover design to assess the role of the human MOR system for touch pleasantness and motivation. Forty-nine male volunteers received 10 mg per-oral morphine, 50 mg per-oral naltrexone and placebo before being brushed on their forearm at three different velocities (0.3, 3 and 30 cm/s). In a touch liking task, pleasantness ratings were recorded after each 15 s brushing trial. In a touch wanting task, participants actively manipulated trial duration through key presses. As expected, 3 cm/s was the preferred velocity, producing significantly higher pleasantness ratings and wanting scores than the other stimuli. Contrary to our hypothesis, MOR drug manipulations did not significantly affect either touch pleasantness or wanting. The null effects were supported by post hoc Bayesian analyses indicating that the models with no drug effect were more than 25 times more likely than the alternative models given the data. We conclude that μ-opioid signalling is unlikely to underpin non-affiliative touch reward in humans.
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Affiliation(s)
- Guro E Løseth
- Department of Psychology, University of Oslo, Blindern, N Oslo, Norway
| | - Marie Eikemo
- Department of Psychology, University of Oslo, Blindern, N Oslo, Norway.,Department of Diagnostic Physics, Oslo University Hospital, Nydalen, N Oslo, Norway
| | - Siri Leknes
- Department of Psychology, University of Oslo, Blindern, N Oslo, Norway
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31
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A Survey of Molecular Imaging of Opioid Receptors. Molecules 2019; 24:molecules24224190. [PMID: 31752279 PMCID: PMC6891617 DOI: 10.3390/molecules24224190] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 01/09/2023] Open
Abstract
The discovery of endogenous peptide ligands for morphine binding sites occurred in parallel with the identification of three subclasses of opioid receptor (OR), traditionally designated as μ, δ, and κ, along with the more recently defined opioid-receptor-like (ORL1) receptor. Early efforts in opioid receptor radiochemistry focused on the structure of the prototype agonist ligand, morphine, although N-[methyl-11C]morphine, -codeine and -heroin did not show significant binding in vivo. [11C]Diprenorphine ([11C]DPN), an orvinol type, non-selective OR antagonist ligand, was among the first successful PET tracers for molecular brain imaging, but has been largely supplanted in research studies by the μ-preferring agonist [11C]carfentanil ([11C]Caf). These two tracers have the property of being displaceable by endogenous opioid peptides in living brain, thus potentially serving in a competition-binding model. Indeed, many clinical PET studies with [11C]DPN or [11C]Caf affirm the release of endogenous opioids in response to painful stimuli. Numerous other PET studies implicate μ-OR signaling in aspects of human personality and vulnerability to drug dependence, but there have been very few clinical PET studies of μORs in neurological disorders. Tracers based on naltrindole, a non-peptide antagonist of the δ-preferring endogenous opioid enkephalin, have been used in PET studies of δORs, and [11C]GR103545 is validated for studies of κORs. Structures such as [11C]NOP-1A show selective binding at ORL-1 receptors in living brain. However, there is scant documentation of δ-, κ-, or ORL1 receptors in healthy human brain or in neurological and psychiatric disorders; here, clinical PET research must catch up with recent progress in radiopharmaceutical chemistry.
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32
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Winterdahl M, Noer O, Orlowski D, Schacht AC, Jakobsen S, Alstrup AKO, Gjedde A, Landau AM. Sucrose intake lowers μ-opioid and dopamine D2/3 receptor availability in porcine brain. Sci Rep 2019; 9:16918. [PMID: 31729425 PMCID: PMC6858372 DOI: 10.1038/s41598-019-53430-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/31/2019] [Indexed: 12/26/2022] Open
Abstract
Excessive sucrose consumption elicits addiction-like craving that may underpin the obesity epidemic. Opioids and dopamine mediate the rewarding effects of drugs of abuse, and of natural rewards from stimuli such as palatable food. We investigated the effects of sucrose using PET imaging with [11C]carfentanil (μ-opioid receptor agonist) and [11C]raclopride (dopamine D2/3 receptor antagonist) in seven female anesthetized Göttingen minipigs. We then gave minipigs access to sucrose solution for one hour on 12 consecutive days and performed imaging again 24 hours after the final sucrose access. In a smaller sample of five minipigs, we performed an additional [11C]carfentanil PET session after the first sucrose exposure. We calculated voxel-wise binding potentials (BPND) using the cerebellum as a region of non-displaceable binding, analyzed differences with statistical non-parametric mapping, and performed a regional analysis. After 12 days of sucrose access, BPND of both tracers had declined significantly in striatum, nucleus accumbens, thalamus, amygdala, cingulate cortex and prefrontal cortex, consistent with down-regulation of receptor densities. After a single exposure to sucrose, we found decreased binding of [11C]carfentanil in nucleus accumbens and cingulate cortex, consistent with opioid release. The lower availability of opioid and dopamine receptors may explain the addictive potential associated with intake of sucrose.
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Affiliation(s)
- Michael Winterdahl
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Ove Noer
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Dariusz Orlowski
- Department of Neurosurgery and CENSE, Aarhus University Hospital, Aarhus, Denmark
| | - Anna C Schacht
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Steen Jakobsen
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Aage K O Alstrup
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Albert Gjedde
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine, University of Southern Denmark & Odense University Hospital, Odense, Denmark.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.,Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Anne M Landau
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark. .,Translational Neuropsychiatry Unit, Aarhus University, Aarhus, Denmark.
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33
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Colom M, Vidal B, Zimmer L. Is There a Role for GPCR Agonist Radiotracers in PET Neuroimaging? Front Mol Neurosci 2019; 12:255. [PMID: 31680859 PMCID: PMC6813225 DOI: 10.3389/fnmol.2019.00255] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
Positron emission tomography (PET) is a molecular imaging modality that enables in vivo exploration of metabolic processes and especially the pharmacology of neuroreceptors. G protein-coupled receptors (GPCRs) play an important role in numerous pathophysiologic disorders of the central nervous system. Thus, they are targets of choice in PET imaging to bring proof concept of change in density in pathological conditions or in pharmacological challenge. At present, most radiotracers are antagonist ligands. In vitro data suggest that properties differ between GPCR agonists and antagonists: antagonists bind to receptors with a single affinity, whereas agonists are characterized by two different affinities: high affinity for receptors that undergo functional coupling to G-proteins, and low affinity for those that are not coupled. In this context, agonist radiotracers may be useful tools to give functional images of GPCRs in the brain, with high sensitivity to neurotransmitter release. Here, we review all existing PET radiotracers used from animals to humans and their role for understanding the ligand-receptor paradigm of GPCR in comparison with corresponding antagonist radiotracers.
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Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France
| | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France.,Institut National des Sciences et Techniques Nucléaires, CEA Saclay, Gif-sur-Yvette, France
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34
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Intranasal naloxone rapidly occupies brain mu-opioid receptors in human subjects. Neuropsychopharmacology 2019; 44:1667-1673. [PMID: 30867551 PMCID: PMC6785104 DOI: 10.1038/s41386-019-0368-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/03/2019] [Accepted: 03/06/2019] [Indexed: 12/14/2022]
Abstract
Nasal spray formulations of naloxone, a mu-opioid receptor (MOR) antagonist, are currently used for the treatment of opioid overdose. They may have additional therapeutic utility also in the absence of opioid agonist drugs, but the onset and duration of action at brain MORs have been inadequately characterized to allow such projections. This study provides initial characterization of brain MOR availability at high temporal resolution following intranasal (IN) naloxone administration to healthy volunteers in the absence of a competing opioid agonist. Fourteen participants were scanned twice using positron emission tomography (PET) and [11C]carfentanil, a selective MOR agonist radioligand. Concentrations of naloxone in plasma and MOR availability (relative to placebo) were monitored from 0 to 60 min and at 300-360 min post naloxone. Naloxone plasma concentrations peaked at ~20 min post naloxone, associated with slightly delayed development of brain MOR occupancy (half of peak occupancy reached at ~10 min). Estimated peak occupancies were 67 and 85% following 2 and 4 mg IN doses, respectively. The estimated half-life of occupancy disappearance was ~100 min. The rapid onset of brain MOR occupancy by IN naloxone, evidenced by the rapid onset of its action in opioid overdose victims, was directly documented in humans for the first time. The employed high temporal-resolution PET method establishes a model that can be used to predict brain MOR occupancy from plasma naloxone concentrations. IN naloxone may have therapeutic utility in various addictions where brain opioid receptors are implicated, such as gambling disorder and alcohol use disorder.
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35
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Roux-en-Y gastric bypass in rat reduces mu-opioid receptor levels in brain regions associated with stress and energy regulation. PLoS One 2019; 14:e0218680. [PMID: 31220174 PMCID: PMC6586324 DOI: 10.1371/journal.pone.0218680] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/06/2019] [Indexed: 12/23/2022] Open
Abstract
Roux-en-Y gastric bypass surgery (RYGB) is the most common and effective weight loss procedure for severe obesity. However, a significant increase in addictive behaviors and new-onset substance use disorder (SUD) are sometimes observed post-surgery. The endogenous opioid system is known to play a major role in motivated behavior and reward, as well as the abuse of substances, including alcohol, tobacco, opioids and highly palatable foods. Here, we examined the effects of RYGB on mu-opioid receptor levels in the brain. Male Sprague-Dawley rats were assigned to one of four groups: standard diet with sham surgery (control), ad libitum high-energy high-fat (HF) diet with sham surgery, calorie restricted HF diet with sham surgery (Sham-FR), or HF diet with RYGB surgery. Control and HF groups were fed their respective diets for 8 weeks, with surgery performed on the eighth week. After 9 weeks on their respective diets post-surgery, animals were sacrificed for mu-opioid receptor autoradiography using the [3H] [D-Ala2,N-Me-Phe4-Gly5-ol]- enkephalin (DAMGO) ligand. Rats with RYGB showed reduced DAMGO binding in the central amygdala compared to sham-operated HF diet controls, and in the hypothalamus compared to high-fat fed Sham-FR. Diet alone did not change [3H] DAMGO binding in any region. These findings show that RYGB surgery, independent of diet or caloric restriction, decreases mu opioid signaling in specific regions important for stress and energy regulation. Thus, RYGB surgery may lead to greater stress sensitivity via downregulated mu opioid signaling in the central amygdala, which may contribute to the observed increased risk in some subjects for addictive behavior.
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36
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Ferrulli A, Macrì C, Terruzzi I, Ambrogi F, Milani V, Adamo M, Luzi L. High frequency deep transcranial magnetic stimulation acutely increases β-endorphins in obese humans. Endocrine 2019; 64:67-74. [PMID: 30406883 DOI: 10.1007/s12020-018-1791-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 10/11/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE In obesity, metabolic and voluntary factors regulate appetite, and a dysregulation of the reward pathway was demonstrated in all addiction disorders. Deep transcranial magnetic stimulation (dTMS) is already used to modulate cerebral dopamine activation in neuro-psychiatric diseases. We presently assess the acute effect of high frequency (HF) and low frequency (LF) dTMS on the modulation of the main neuropeptides and neurotransmitters involved in the reward pathway in obese subjects. METHODS This study was designed as a double-blind, sham-controlled, randomized clinical trial. Thirty-three obese patients (9 males, 24 females, age 48.1 ± 10.6, BMI 36.4 ± 4.7) were enrolled in the study. All patients were studied during a single dTMS session and blood aliquots were drawn before and after a single dTMS session. Metabolic and neuro-endocrine parameters were evaluated before and after: (1) 18 Hz dTMS (HF, 13 patients); (2) 1 Hz dTMS (LF, 10 patients); (3) Sham treatment (Sham, 10 patients). RESULTS No statistically significant variations in metabolic parameters, systolic and diastolic blood pressure, and heart rate were shown acutely. HF showed a significant increase of β-endorphin compared to other groups (p = 0.048); a significant increase of ghrelin in LF (p = 0.041) was also demonstrated. CONCLUSIONS A single session of HF dTMS treatment determines in obese subjects an acute increase of β-endorphin level, indicating an activation of the reward pathway. The present findings constitute proof of principle for a potential application of this methodology in obesity treatment.
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Affiliation(s)
- Anna Ferrulli
- Endocrinology and Metabolism Division and Metabolism Research Center, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Concetta Macrì
- Endocrinology and Metabolism Division and Metabolism Research Center, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Ileana Terruzzi
- Laboratory of Nutrigenomics, Metabolism and Cell Differentiation, Diabetes Research Institute, San Raffaele Hospital, Milan, Italy
| | - Federico Ambrogi
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Valentina Milani
- Scientific Directorate, IRCCS Policlinico San Donato, Milan, Italy
| | - Michela Adamo
- Endocrinology and Metabolism Division and Metabolism Research Center, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Livio Luzi
- Endocrinology and Metabolism Division and Metabolism Research Center, IRCCS Policlinico San Donato, San Donato Milanese, Italy.
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
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37
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Støving RK. MECHANISMS IN ENDOCRINOLOGY: Anorexia nervosa and endocrinology: a clinical update. Eur J Endocrinol 2019; 180:R9-R27. [PMID: 30400050 PMCID: PMC6347284 DOI: 10.1530/eje-18-0596] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/25/2018] [Indexed: 12/17/2022]
Abstract
Anorexia nervosa is a syndrome, that is collections of symptoms, which is not defined by its etiology. The severe cases are intractable. The syndrome is associated with multiple, profound endocrine alterations which may be adaptive, reactive or etiologic. Adaptive changes potentially may be inappropriate in clinical settings such as inpatient intensive re-nutrition or in a setting with somatic comorbidity. Electrolyte levels must be closely monitored during the refeeding process, and the need for weight gain must be balanced against potentially fatal refeeding complications. An important focus of clinical research should be to identify biomarkers associated with different stages of weight loss and re-nutrition combined with psychometric data. Besides well-established peripheral endocrine actions, several hormones also are released directly to different brain areas, where they may exert behavioral and psychogenic actions that could offer therapeutic targets. We need reliable biomarkers for predicting outcome and to ensure safe re-nutrition, however, first of all we need them to explore the metabolism in anorexia nervosa to open new avenues with therapeutic targets. A breakthrough in our understanding and treatment of this whimsical disease remains. Considering this, the aim of the present review is to provide an updated overview of the many endocrine changes in a clinical perspective.
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Affiliation(s)
- René Klinkby Støving
- Nutrition Clinic, Center for Eating Disorders, Odense University Hospital
- Endocrine Elite Research Centre, Institute of Clinical Research, University of South Denmark, Faculty of Health Sciences
- Psychiatric Services in the Region of Southern Denmark, Odense, Denmark
- Correspondence should be addressed to R K Støving;
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38
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Karjalainen T, Seppälä K, Glerean E, Karlsson HK, Lahnakoski JM, Nuutila P, Jääskeläinen IP, Hari R, Sams M, Nummenmaa L. Opioidergic Regulation of Emotional Arousal: A Combined PET–fMRI Study. Cereb Cortex 2018; 29:4006-4016. [DOI: 10.1093/cercor/bhy281] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 10/11/2018] [Indexed: 01/17/2023] Open
Abstract
Abstract
Emotions can be characterized by dimensions of arousal and valence (pleasantness). While the functional brain bases of emotional arousal and valence have been actively investigated, the neuromolecular underpinnings remain poorly understood. We tested whether the opioid and dopamine systems involved in reward and motivational processes would be associated with emotional arousal and valence. We used in vivo positron emission tomography to quantify μ-opioid receptor and type 2 dopamine receptor (MOR and D2R, respectively) availability in brains of 35 healthy adult females. During subsequent functional magnetic resonance imaging carried out to monitor hemodynamic activity, the subjects viewed movie scenes of varying emotional content. Arousal and valence were associated with hemodynamic activity in brain regions involved in emotional processing, including amygdala, thalamus, and superior temporal sulcus. Cerebral MOR availability correlated negatively with the hemodynamic responses to arousing scenes in amygdala, hippocampus, thalamus, and hypothalamus, whereas no positive correlations were observed in any brain region. D2R availability—here reliably quantified only in striatum—was not associated with either arousal or valence. These results suggest that emotional arousal is regulated by the MOR system, and that cerebral MOR availability influences brain activity elicited by arousing stimuli.
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Affiliation(s)
| | | | - Enrico Glerean
- Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering (NBE), Aalto University, Aalto, Espoo, Finland
- Department of Computer Science, Aalto University, Aalto, Espoo, Finland
- Helsinki Institute for Information Technology, Aalto, Espoo, Finland
| | | | - Juha M Lahnakoski
- Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering (NBE), Aalto University, Aalto, Espoo, Finland
- Independent Max Planck Research Group for Social Neuroscience, Max Planck Institute of Psychiatry, Munich, Germany
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Iiro P Jääskeläinen
- Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering (NBE), Aalto University, Aalto, Espoo, Finland
| | - Riitta Hari
- Department of Art, Aalto University, Aalto, Espoo, Finland
| | - Mikko Sams
- Brain and Mind Laboratory, Department of Neuroscience and Biomedical Engineering (NBE), Aalto University, Aalto, Espoo, Finland
- Department of Computer Science, Aalto University, Aalto, Espoo, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Psychology, University of Turku, Turku, Finland
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Prevalence of obesity for opioid- and stimulant-dependent participants in substance use treatment clinical trials. Drug Alcohol Depend 2018; 190:255-262. [PMID: 30077926 DOI: 10.1016/j.drugalcdep.2018.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 06/08/2018] [Accepted: 06/13/2018] [Indexed: 12/14/2022]
Abstract
AIMS To estimate obesity prevalence among drug-dependent individuals and to compare prevalence across different types of drug dependence. METHODS 1596 opioid- and/or stimulant-dependent participants were extracted from six clinical trials within the National Drug Abuse Treatment Clinical Trials Network of the National Institute on Drug Abuse (NIDA CTN) to estimate obesity prevalence among drug-dependent users. Age-, sex-, and race-matched National Health and Nutrition Examination Survey (NHANES) samples were used as a general population reference. Standardized prevalence ratios (SPRs) were calculated to compare the CTN sample to NHANES as well as to compare within the CTN sample. Logistic regression estimated associations between the type of drug dependence and obesity. RESULTS The standardized obesity prevalence among the drug-dependent CTN trial participants was 67% of expected for age-, sex- and race-matched NIHANES participants (SPR = 0.67, 95% CI: 0.60-0.74). Obesity was least prevalent among opioid-dependent-only participants (SPR = 0.36, 95% CI: 0.27-0.46 compared to the NHANES, and SPR = 0.33, 95% CI: 0.23-0.46 compared to the stimulant-dependent-only participants). Compared to stimulant-dependent-only users (p < 0.0001), the odds of obesity were 67% lower among opioid-dependent-only users (adjusted odds ratio [AOR] = 0.33, 95% CI: 0.23-0.46) and 33% lower among opioid and stimulant-co-dependent users (AOR = 0.67, 95%CI: 0.49-0.90) after controlling for age, sex, race, education and employment pattern. CONCLUSIONS The prevalence of obesity among drug-dependent clinical trial participants was lower than the general population, and lowest among opioid-dependent-only users, suggesting an inverse relationship between obesity prevalence and drug dependence, most notable among opioid-dependent-only users.
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Joutsa J, Karlsson HK, Majuri J, Nuutila P, Helin S, Kaasinen V, Nummenmaa L. Binge eating disorder and morbid obesity are associated with lowered mu-opioid receptor availability in the brain. Psychiatry Res Neuroimaging 2018; 276:41-45. [PMID: 29655552 DOI: 10.1016/j.pscychresns.2018.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 01/27/2018] [Accepted: 03/02/2018] [Indexed: 01/17/2023]
Abstract
Both morbid obesity and binge eating disorder (BED) have previously been linked with aberrant brain opioid function. Behaviorally these two conditions are however different suggesting also differences in neurotransmitter function. Here we directly compared mu-opioid receptor (MOR) availability between morbidly obese and BED subjects. Seven BED and nineteen morbidly obese (non-BED) patients, and thirty matched control subjects underwent positron emission tomography (PET) with MOR-specific ligand [11C]carfentanil. Both subjects with morbid obesity and BED had widespread reduction in [11C]carfentanil binding compared to control subjects. However, there was no significant difference in brain MOR binding between subjects with morbid obesity and BED. Thus, our results indicate that there is common brain opioid abnormality in behaviorally different eating disorders involving obesity.
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Affiliation(s)
- Juho Joutsa
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.
| | | | - Joonas Majuri
- Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland; Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Semi Helin
- Turku PET Centre, University of Turku, Turku, Finland
| | - Valtteri Kaasinen
- Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland; Department of Psychology, University of Turku, Turku, Finland
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41
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Saanijoki T, Nummenmaa L, Tuulari JJ, Tuominen L, Arponen E, Kalliokoski KK, Hirvonen J. Aerobic exercise modulates anticipatory reward processing via the μ-opioid receptor system. Hum Brain Mapp 2018; 39:3972-3983. [PMID: 29885086 DOI: 10.1002/hbm.24224] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 04/20/2018] [Accepted: 05/10/2018] [Indexed: 01/18/2023] Open
Abstract
Physical exercise modulates food reward and helps control body weight. The endogenous µ-opioid receptor (MOR) system is involved in rewarding aspects of both food and physical exercise, yet interaction between endogenous opioid release following exercise and anticipatory food reward remains unresolved. Here we tested whether exercise-induced opioid release correlates with increased anticipatory reward processing in humans. We scanned 24 healthy lean men after rest and after a 1 h session of aerobic exercise with positron emission tomography (PET) using MOR-selective radioligand [11 C]carfentanil. After both PET scans, the subjects underwent a functional magnetic resonance imaging (fMRI) experiment where they viewed pictures of palatable versus nonpalatable foods to trigger anticipatory food reward responses. Exercise-induced changes in MOR binding in key regions of reward circuit (amygdala, thalamus, ventral and dorsal striatum, and orbitofrontal and cingulate cortices) were used to predict the changes in anticipatory reward responses in fMRI. Exercise-induced changes in MOR binding correlated negatively with the exercise-induced changes in neural anticipatory food reward responses in orbitofrontal and cingulate cortices, insula, ventral striatum, amygdala, and thalamus: higher exercise-induced opioid release predicted higher brain responses to palatable versus nonpalatable foods. We conclude that MOR activation following exercise may contribute to the considerable interindividual variation in food craving and consumption after exercise, which might promote compensatory eating and compromise weight control.
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Affiliation(s)
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland.,Department of Psychology, University of Turku, Turku, Finland
| | | | - Lauri Tuominen
- Turku PET Centre, University of Turku, Turku, Finland.,Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | | | | | - Jussi Hirvonen
- Turku PET Centre, University of Turku, Turku, Finland.,Department of Radiology, Turku University Hospital, Turku, Finland
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42
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Nummenmaa L, Saanijoki T, Tuominen L, Hirvonen J, Tuulari JJ, Nuutila P, Kalliokoski K. μ-opioid receptor system mediates reward processing in humans. Nat Commun 2018; 9:1500. [PMID: 29662095 PMCID: PMC5902580 DOI: 10.1038/s41467-018-03848-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/16/2018] [Indexed: 12/19/2022] Open
Abstract
The endogenous μ-opioid receptor (MOR) system regulates motivational and hedonic processing. We tested directly whether individual differences in MOR are associated with neural reward responses to food pictures in humans. We scanned 33 non-obese individuals with positron emission tomography (PET) using the MOR-specific radioligand [11C]carfentanil. During a functional magnetic resonance imaging (fMRI) scan, the subjects viewed pictures of appetizing versus bland foods to elicit reward responses. MOR availability was measured in key components of the reward and emotion circuits and used to predict BOLD-fMRI responses to foods. Viewing palatable versus bland foods activates regions involved in homeostatic and reward processing, such as amygdala, ventral striatum, and hypothalamus. MOR availability in the reward and emotion circuit is negatively associated with the fMRI reward responses. Variation in MOR availability may explain why some people feel an urge to eat when encountering food cues, increasing risk for weight gain and obesity. μ-opioid signalling has a known role in the response to various rewarding stimuli, including pleasant foods. Here, Nummenmaa et al. show using PET and fMRI that individual differences in brain μ-opioid receptor density predict the strength of the neural response to highly palatable foods in humans
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Affiliation(s)
- Lauri Nummenmaa
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland. .,Department of Psychology, University of Turku, 20014, Turku, Finland.
| | - Tiina Saanijoki
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Lauri Tuominen
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Jussi Hirvonen
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland.,Department of Radiology, University of Turku, 20014, Turku, Finland
| | - Jetro J Tuulari
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
| | - Kari Kalliokoski
- Turku PET Centre, University of Turku and Turku University Hospital, 20520, Turku, Finland
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Hankir MK, Seyfried F, Miras AD, Cowley MA. Brain Feeding Circuits after Roux-en-Y Gastric Bypass. Trends Endocrinol Metab 2018; 29:218-237. [PMID: 29475578 DOI: 10.1016/j.tem.2018.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/17/2018] [Accepted: 01/25/2018] [Indexed: 12/12/2022]
Abstract
Metabolic surgical procedures, such as Roux-en-Y gastric bypass (RYGB), uniquely reprogram feeding behavior and body weight in obese subjects. Clinical neuroimaging and animal studies are only now beginning to shed light on some of the underlying central mechanisms. We present here the roles of key brain neurotransmitter/neuromodulator systems in food choice, value, and intake at various stages after RYGB. In doing so, we elaborate on how known signals emanating from the reorganized gut, including peptide hormones and microbiota products, impinge on newly mapped homeostatic and hedonic brain feeding circuits. Continued progress in the rapidly evolving field of metabolic surgery will inform the design of more effective weight-loss compounds.
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Affiliation(s)
- Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany; German Research Foundation Collaborative Research Center in Obesity Mechanisms, University of Leipzig, Leipzig, Saxony 04103, Germany.
| | - Florian Seyfried
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany
| | - Alexander D Miras
- Department of Investigative Science, Imperial College London Academic Healthcare Centre, London W12 0NN, UK
| | - Michael A Cowley
- Metabolic Disease and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia; Department of Physiology, Monash University, Victoria 3800, Australia
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Fujita M, Ide S, Ikeda K. Opioid and nondopamine reward circuitry and state-dependent mechanisms. Ann N Y Acad Sci 2018. [PMID: 29512887 DOI: 10.1111/nyas.13605] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A common notion is that essentially all addictive drugs, including opioids, activate dopaminergic pathways in the brain reward system, and the inappropriate use of such drugs induces drug dependence. However, an opioid reward response is reportedly still observed in several models of dopamine depletion, including in animals that are treated with dopamine blockers, animals that are subjected to dopaminergic neuron lesions, and dopamine-deficient mice. The intracranial self-stimulation response is enhanced by stimulants but reduced by morphine. These findings suggest that dopaminergic neurotransmission may not always be required for opioid reward responses. Previous findings also indicate the possibility that dopamine-independent opioid reward may be observed in opioid-naive states but not in opioid-dependent states. Therefore, a history of opioid use should be considered when evaluating the dopamine dependency of opioid reward.
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Affiliation(s)
- Masayo Fujita
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Soichiro Ide
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazutaka Ikeda
- Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Thobois S, Brefel-Courbon C, Le Bars D, Sgambato-Faure V. Molecular Imaging of Opioid System in Idiopathic Parkinson's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 141:275-303. [DOI: 10.1016/bs.irn.2018.07.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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