1
|
Escartín Pérez RE, Mancilla Díaz JM, Cortés Salazar F, López Alonso VE, Florán Garduño B. CB1/5-HT/GABA interactions and food intake regulation. PROGRESS IN BRAIN RESEARCH 2021; 259:177-196. [PMID: 33541676 DOI: 10.1016/bs.pbr.2021.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Despite historically the serotonergic, GABAergic, and cannabinoid systems have been shown to play a crucial role in the central regulation of eating behavior, interest in the study of the interactions of these neurotransmission systems has only now been investigated. Current evidence suggests that serotonin may influence normal and pathological eating behavior in significantly more complex ways than was initially thought. This knowledge has opened the possibility of exploring the potential clinical utility of new therapeutic strategies more effective and safer than the current approaches to treat pathological eating behavior. Furthermore, the nature and complexity of the interactions between these neurotransmitter systems have provided a better understanding of the pathophysiological mechanisms not only of eating behavior and eating disorders but also of some of the comorbidities associated with modulation of cortical circuits, which are involved in high order cognitive processes. Accordingly, in the present chapter, the clinical and experimental findings of the interactions between serotonin, GABA, and cannabinoids are synthesized, emphasizing the pharmacological, neurophysiological, and neuroanatomical aspects that could potentially improve the current therapeutic approaches against pathological eating behavior.
Collapse
Affiliation(s)
- Rodrigo Erick Escartín Pérez
- Facultad de Estudios Superiores Iztacala, División de Investigación y Posgrado, Laboratorio de Neurobiología de la Alimentación, Universidad Nacional Autónoma de México, México, México.
| | - Juan Manuel Mancilla Díaz
- Facultad de Estudios Superiores Iztacala, División de Investigación y Posgrado, Laboratorio de Neurobiología de la Alimentación, Universidad Nacional Autónoma de México, México, México
| | - Felipe Cortés Salazar
- Facultad de Estudios Superiores Iztacala, División de Investigación y Posgrado, Laboratorio de Neurobiología de la Alimentación, Universidad Nacional Autónoma de México, México, México
| | - Verónica Elsa López Alonso
- Facultad de Estudios Superiores Iztacala, División de Investigación y Posgrado, Laboratorio de Neurobiología de la Alimentación, Universidad Nacional Autónoma de México, México, México
| | - Benjamín Florán Garduño
- Facultad de Estudios Superiores Iztacala, División de Investigación y Posgrado, Laboratorio de Neurobiología de la Alimentación, Universidad Nacional Autónoma de México, México, México
| |
Collapse
|
2
|
Abstract
Elucidating the functions of a particular gene is paramount to the understanding of how its dysfunction contributes to disease. This is especially important when the gene is implicated in multiple different disorders. One such gene is methyl-CpG-binding protein 2 (MECP2), which has been most prominently associated with the neurodevelopmental disorder Rett syndrome, as well as major neuropsychiatric disorders such as autism and schizophrenia. Being initially identified as a transcriptional regulator that modulates gene expression and subsequently also shown to be involved in other molecular events, dysfunction of the MeCP2 protein has the potential to affect many cellular processes. In this chapter, we will briefly review the functions of the MeCP2 protein and how its mutations are implicated in Rett syndrome and other neuropsychiatric disorders. We will further discuss about the mouse models that have been generated to specifically dissect the function of MeCP2 in different cell types and brain regions. It is envisioned that such thorough and targeted examination of MeCP2 functions can aid in enlightening the role that it plays in normal and dysfunctional physiological systems.
Collapse
Affiliation(s)
- Eunice W M Chin
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Eyleen L K Goh
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
- Department of Research, National Neuroscience Institute, Singapore, Singapore.
- Neuroscience Academic Clinical Programme, Singhealth Duke-NUS Academic Medical Center, Singapore, Singapore.
| |
Collapse
|
3
|
Lutter M, Croghan AE, Cui H. Escaping the Golden Cage: Animal Models of Eating Disorders in the Post-Diagnostic and Statistical Manual Era. Biol Psychiatry 2016; 79:17-24. [PMID: 25777657 DOI: 10.1016/j.biopsych.2015.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/21/2015] [Accepted: 02/07/2015] [Indexed: 12/13/2022]
Abstract
Eating disorders (EDs) are severe, life-threatening mental illnesses characterized by marked disturbances in body image and eating patterns. Attempts to understand the neurobiological basis of EDs have been hindered by the perception that EDs are primarily socially reinforced behaviors and not the result of a pathophysiologic process. This view is reflected by the diagnostic criteria of anorexia nervosa and bulimia nervosa, which emphasize intrapsychic conflicts such as "inability to maintain body weight," "undue influence of body weight or shape on self-evaluation," and "denial of the seriousness of low body weight" over neuropsychological measures. The neuropsychological constructs introduced within the research domain criteria (RDoC) matrix offer new hope for determining the neural substrate underlying the biological predisposition to EDs. We present selected studies demonstrating deficits in patients with EDs within each domain of the RDoC and propose a set of behavioral tasks in model systems that reflect aspects of that deficit. Finally, we propose a battery of tasks to examine comprehensively the function of neural circuits relevant to the development of EDs.
Collapse
Affiliation(s)
- Michael Lutter
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, Iowa..
| | - Anna E Croghan
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, Iowa
| | - Huxing Cui
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, Iowa
| |
Collapse
|
4
|
Cui H, Lu Y, Khan MZ, Anderson RM, McDaniel L, Wilson HE, Yin TC, Radley JJ, Pieper AA, Lutter M. Behavioral disturbances in estrogen-related receptor alpha-null mice. Cell Rep 2015; 11:344-50. [PMID: 25865889 PMCID: PMC4440329 DOI: 10.1016/j.celrep.2015.03.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/24/2015] [Accepted: 03/12/2015] [Indexed: 11/24/2022] Open
Abstract
Eating disorders, such as anorexia nervosa and bulimia nervosa, are common and severe mental illnesses of unknown etiology. Recently, we identified a rare missense mutation in the transcription factor estrogen-related receptor alpha (ESRRA) that is associated with the development of eating disorders. However, little is known about ESRRA function in the brain. Here, we report that Esrra is expressed in the mouse brain and demonstrate that Esrra levels are regulated by energy reserves. Esrra-null female mice display a reduced operant response to a high-fat diet, compulsivity/behavioral rigidity, and social deficits. Selective Esrra knockdown in the prefrontal and orbitofrontal cortices of adult female mice recapitulates reduced operant response and increased compulsivity, respectively. These results indicate that Esrra deficiency in the mouse brain impairs behavioral responses in multiple functional domains.
Collapse
Affiliation(s)
- Huxing Cui
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yuan Lu
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Michael Z Khan
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Rachel M Anderson
- Department of Psychology, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Latisha McDaniel
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Hannah E Wilson
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Terry C Yin
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jason J Radley
- Department of Psychology, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA; Interdisciplinary Neuroscience Program, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Andrew A Pieper
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA; Department of Neurology, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA; Interdisciplinary Neuroscience Program, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | - Michael Lutter
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA; Interdisciplinary Neuroscience Program, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA.
| |
Collapse
|
5
|
Jawaid H, Ali S. Genetics in psychiatry – diagnostic support or an illness classification! ACTA MEDICA INTERNATIONAL 2015. [DOI: 10.5530/ami.2015.4.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
6
|
Effects of CB1 cannabinoid receptor activation in the nucleos accumbens shell on feeding behavior. ACTA COLOMBIANA DE PSICOLOGIA 2014. [DOI: 10.14718/acp.2014.17.2.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Obesity and its related pathologies are well- known health hazards. Although obesity and overweight have multifactorial causes, overeating is common in both of these conditions. According to animal models, endocannabinoids and their receptors in the brain play a key role in the genesis and development of obesity. It has been proposed that the cannabinoid receptors CB1 (RCB1) expressed in the nucleus accumbens shell (NAC) are involved in the increase of the hedonic properties of food. To test this hypothesis, thisstudy aimed to assess the effects of activating the NACs RCB1 on standard food intake during the light phase of the light-dark cycle. The effects of activating the RCB1 with CP 55,940 and WIN 55-212-2 (0.125, 0.25 and 0.5 nmol) in the NACS on feeding behavior and the behavioral satiety sequence of rats were assessed. It wasfound that both agonists increased food intake and delayed expression of satiety during the light phase. These results suggest that cannabinoid agonists encourage food intake when motivation is low and palatability is normal.
Collapse
|
7
|
Perello M, Valdivia S, García Romero G, Raingo J. Considerations about rodent models of binge eating episodes. Front Psychol 2014; 5:372. [PMID: 24808881 PMCID: PMC4010779 DOI: 10.3389/fpsyg.2014.00372] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/08/2014] [Indexed: 01/27/2023] Open
Affiliation(s)
- Mario Perello
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA) La Plata, Argentina
| | - Spring Valdivia
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA) La Plata, Argentina
| | - Guadalupe García Romero
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA) La Plata, Argentina
| | - Jesica Raingo
- Laboratory of Electrophysiology, Multidisciplinary Institute of Cell Biology, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA) La Plata, Argentina
| |
Collapse
|
8
|
Das S, Gupta R, Dhyani M, Raghuvanshi S. Kleine-Levin syndrome: a case report and review of literature. Pediatr Neurol 2014; 50:411-6. [PMID: 24630285 DOI: 10.1016/j.pediatrneurol.2014.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/20/2013] [Accepted: 01/01/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Kleine-Levin syndrome presents with recurrent hypersomnia along with a number of other neuropsychiatric features, of which hyperorality has not been described frequently. METHOD We report a male adolescent who presented with recurrent hypersomnia, hypersexuality, and hyperorality. Magnetic resonance imaging of the brain and overnight polysomnography followed by a multiple sleep latency tests were ordered. Excessive daytime sleepiness was assessed with the Epworth Sleepiness Scale. RESULTS Magnetic resonance imaging of the brain did not reveal any abnormality. Overnight video-synchronized polysomnography and multiple sleep latency tests ruled out narcolepsy. Epworth Sleepiness Scale score at baseline was 22. He was prescribed lithium carbonate 300 mg twice a day. The symptoms improved within a week after starting lithium carbonate therapy. CONCLUSION Kleine-Levin syndrome may present with hyperorality, and our patient responded well to lithium carbonate therapy.
Collapse
Affiliation(s)
- Sourav Das
- Department of Psychiatry and Sleep Clinic, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India
| | - Ravi Gupta
- Department of Psychiatry and Sleep Clinic, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India.
| | - Mohan Dhyani
- Department of Psychiatry and Sleep Clinic, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India
| | - Shailendra Raghuvanshi
- Department of Radiology, Himalayan Institute of Medical Sciences, Doiwala, Dehradun, India
| |
Collapse
|
9
|
Acute high fat diet consumption activates the mesolimbic circuit and requires orexin signaling in a mouse model. PLoS One 2014; 9:e87478. [PMID: 24466352 PMCID: PMC3900715 DOI: 10.1371/journal.pone.0087478] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/24/2013] [Indexed: 12/03/2022] Open
Abstract
Overconsumption of palatable energy-dense foods has negative health implications and it is associated with obesity and several eating disorders. Currently, little is known about the neuronal circuitries activated by the acute ingestion of a rewarding stimulus. Here, we used a combination of immunohistochemistry, pharmacology and neuronal tracing analyses to examine the role of the mesolimbic system in general, and the orexin neurons in particular, in a simple experimental test in which naïve mice are allowed to spontaneously eat a pellet of a high fat diet (HFD) for 2 h. We found that acute HFD activates c-Fos expression in several reward-related brain areas, including the ventral tegmental area (VTA), nucleus accumbens, central amygdala and lateral hypothalamic area. We also found that: i- HFD-mediated orosensory stimulation was required for the mesolimbic pathway activation, ii- acute HFD differentially activates dopamine neurons of the paranigral, parabrachial pigmented and interfascicular sub-regions of the VTA, and iii- orexin neurons of the lateral hypothalamic area are responsive to acute HFD. Moreover, orexin signaling blockade, with the orexin 1 receptor antagonist SB-334867, reduces acute HFD consumption and c-Fos induction in the VTA but not in the other mesolimbic nuclei under study. Finally, we found that most orexin neurons responsive to acute HFD innervate the VTA. Our results show that acute HFD consumption recruits the mesolimbic system and that the full manifestation of this eating behavior requires the activation of orexin signaling.
Collapse
|
10
|
Association between melanocortin-4 receptor mutations and eating behaviors in obese patients: a case--control study. Int J Obes (Lond) 2013; 38:883-5. [PMID: 24105491 DOI: 10.1038/ijo.2013.190] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/04/2013] [Accepted: 09/24/2013] [Indexed: 12/29/2022]
Abstract
Melanocortin-4 receptor (MC4R) gene mutations are involved in the leptin-melanocortin pathways that control food intake. The effect of these mutations on eating behavior phenotypes is still debated. To determine the association between functional MC4R mutations and eating behaviors, dietary intake and physical activity, we sequenced the MC4R gene in 4653 obese adults. Among them, 19 adults carriers of functional MC4R mutation were matched on age, sex and body mass index with two randomly-paired controls without MC4R mutation (n=57). We found that eating behaviors and physical activity did not differ between groups. In particular, cases were not at increased risk of binge eating disorders. Subjects carriers of MC4R mutation reported a higher proportion of dietary carbohydrates intakes (43.2±7.1 and 39.2±8.1% of total energy intake, respectively, P=0.048) and a lower proportion of dietary lipids (34.3±6.7 and 38.5±6.7% of total energy intake, respectively, P=0.018). In conclusion, mutation carriers differ from controls by a higher consumption of carbohydrates counterbalanced by a lower consumption of lipids expressed as percentage of total energy intake. However, functional MC4R mutations do not have a higher risk of compulsive eating contrary to what was previously suggested.
Collapse
|
11
|
Valette M, Bellisle F, Carette C, Poitou C, Dubern B, Paradis G, Hercberg S, Muzard L, Clément K, Czernichow S. Eating behaviour in obese patients with melanocortin-4 receptor mutations: a literature review. Int J Obes (Lond) 2012; 37:1027-35. [PMID: 23147118 DOI: 10.1038/ijo.2012.169] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 09/07/2012] [Accepted: 09/09/2012] [Indexed: 11/09/2022]
Abstract
Melanocortin-4 receptor (MC4R) mutations are the most common known cause of monogenic obesity and an important contributor to polygenic obesity. MC4R mutations with partial or total loss of function, as well as the variant rs17782313 mapped near MC4R, are positively associated with obesity. MC4R is involved in the leptin-melanocortin signalling system, located in hypothalamic nuclei, that controls food intake via both anorexigenic or orexigenic signals. Impairment in this receptor might affect eating behaviours. Thus, in the case of MC4R mutation carriers, obesity could be related, at least partly, to inadequate control over eating behaviours. Many published studies address eating behaviours in MC4R mutation carriers. Most studies focus on binge eating disorder, whereas others examine various aspects of intake and motivation. Up to now, no evaluation of this literature has been performed. In this review, we examine the available literature on eating behaviours in carriers of MC4R mutations and variant rs17782313 near MC4R gene. We address binge eating disorder, bulimia nervosa, mealtime hyperphagia, snacking, psychological factors, satiety responsiveness and intake of energy and macro/micronutrient. In a small number of studies, MC4R mutations seem to impair eating behaviours or motivation, but no clear causal effects can be found in the balance of the evidence presented. Improvements in methodologies will be necessary to clarify the behavioural effects of MC4R mutations.
Collapse
Affiliation(s)
- M Valette
- Nutritional Epidemiology Research Unit-UMR U557 INSERM, Paris 13 University, CRNH-IdF, Bobigny, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Mercer RE, Wevrick R. Energy homeostasis in Prader-Willi syndrome: how clinical research informs studies of animal models of genetic obesity: comment on "Nutritional phases in Prader-Willi syndrome," Miller et al., 2011. Am J Med Genet Part A, 155:1040-1049. Am J Med Genet A 2012; 158A:966-8. [PMID: 22419655 DOI: 10.1002/ajmg.a.35249] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 12/26/2011] [Indexed: 11/06/2022]
|
13
|
Wathen AB, West ES, Lydic R, Baghdoyan HA. Olanzapine causes a leptin-dependent increase in acetylcholine release in mouse prefrontal cortex. Sleep 2012; 35:315-23. [PMID: 22379237 PMCID: PMC3274332 DOI: 10.5665/sleep.1686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
STUDY OBJECTIVES The atypical antipsychotic olanzapine is used effectively for treating symptoms of schizophrenia and bipolar disorder. Unwanted effects of olanzapine include slowing of the electroencephalogram (EEG) during wakefulness and increased circulating levels of leptin. The mechanisms underlying the desired and undesired effects of olanzapine are poorly understood. Sleep and wakefulness are modulated by acetylcholine (ACh) in the prefrontal cortex, and leptin alters cholinergic transmission. This study tested the hypothesis that olanzapine interacts with leptin to regulate ACh release in the prefrontal cortex. DESIGN Within/between subjects. SETTING University of Michigan. PATIENTS OR PARTICIPANTS Adult male C57BL/6J (B6) mice (n = 33) and B6.V-Lep(ob) (leptin-deficient) mice (n = 31). INTERVENTIONS Olanzapine was delivered to the prefrontal cortex by microdialysis. Leptin-replacement in leptin-deficient mice was achieved using subcutaneous micro-osmotic pumps. MEASUREMENTS AND RESULTS Olanzapine caused a concentration-dependent increase in ACh release in B6 and leptin-deficient mice. Olanzapine was 230-fold more potent in leptin-deficient than in B6 mice for increasing ACh release, yet olanzapine caused a 51% greater ACh increase in B6 than in leptin-deficient mice. Olanzapine had no effect on recovery time from general anesthesia. Olanzapine increased EEG power in the delta (0.5-4 Hz) range. Thus, olanzapine dissociated the normal coupling between increased cortical ACh release, increased behavioral arousal, and EEG activation. Leptin replacement significantly enhanced (75%) the olanzapine-induced increase in ACh release. CONCLUSION Replacing leptin by systemic administration restored the olanzapine-induced enhancement of ACh release in the prefrontal cortex of leptin-deficient mouse.
Collapse
Affiliation(s)
| | - Emily S. West
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI
| | - Ralph Lydic
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI
| | | |
Collapse
|
14
|
Cui H, Mason BL, Lee C, Nishi A, Elmquist JK, Lutter M. Melanocortin 4 receptor signaling in dopamine 1 receptor neurons is required for procedural memory learning. Physiol Behav 2012; 106:201-10. [PMID: 22342812 DOI: 10.1016/j.physbeh.2012.01.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 11/24/2022]
Abstract
It is now widely recognized that exposure to palatable foods engages reward circuits that promote over-eating and facilitate the development of obesity. While the melanocortin 4 receptor (MC4R) has previously been shown to regulate food intake and energy expenditure, little is known about its role in food reward. We demonstrate that MC4R is co-expressed with the dopamine 1 receptor (D1R) in the ventral striatum. While MC4R-null mice are hyperphagic and obese, they exhibit impairments in acquisition of operant responding for a high fat reinforcement. Restoration of MC4R signaling in D1R neurons normalizes procedural learning without affecting motivation to obtain high fat diet. MC4R signaling in D1R neurons is also required for learning in a non-food-reinforced version of the cued water maze. Finally, MC4R signaling in neostriatal slices increases phosphorylation of the Thr34 residue of DARPP-32, a protein phosphatase-1 inhibitor that regulates synaptic plasticity. These data identify a novel requirement for MC4R signaling in procedural memory learning.
Collapse
Affiliation(s)
- Huxing Cui
- Department of Internal Medicine (Division of Hypothalamic Research), University of Texas Southwestern Medical Center Dallas, Dallas, TX 75390-9127, United States
| | | | | | | | | | | |
Collapse
|