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Kim GW, Lin JE, Waldman SA. GUCY2C: at the intersection of obesity and cancer. Trends Endocrinol Metab 2013; 24:165-73. [PMID: 23375388 PMCID: PMC3617062 DOI: 10.1016/j.tem.2013.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/26/2012] [Accepted: 01/02/2013] [Indexed: 12/13/2022]
Abstract
Guanylyl cyclase C (GUCY2C) has canonical centrality in defense of key intestinal homeostatic mechanisms, encompassing fluid and electrolyte balance, epithelial dynamics, antitumorigenesis, and intestinal barrier function. Recent discoveries expand the homeostatic role of GUCY2C to reveal a novel gut-brain endocrine axis regulating appetite, anchored by hypothalamic GUCY2C which is responsive to intestine-derived uroguanylin. Thus, GUCY2C may represent a new target for anti-obesity pharmacotherapy. Moreover, the coincident regulation of energy balance and tumor suppression by a single hormone receptor system suggests that the GUCY2C axis might contribute to the established relationship between obesity and colorectal cancer. This confluence suggests that hormone supplementation to reconstitute GUCY2C signaling may be an elegant strategy to reverse both pathophysiologic processes.
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Affiliation(s)
- Gilbert W Kim
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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252
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Abstract
Obesity is a cause of sleep breathing disorders that result in excessive daytime sleepiness. We describe the adaptive strategy used by an obese person who started to snort cocaine to remedy incoercible drowsiness affecting his working financial skills. Clinical workup documented severe sleep apnea, which was treated by noninvasive ventilation and resulted in withdrawing cocaine abuse. Undiagnosed sleep disorders may trigger surreptitious psychostimulant abuse in vulnerable individuals.
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253
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Styn MA, Bovbjerg DH, Lipsky S, Erblich J. Cue-induced cigarette and food craving: a common effect? Addict Behav 2013; 38:1840-3. [PMID: 23262259 DOI: 10.1016/j.addbeh.2012.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 07/27/2012] [Accepted: 09/06/2012] [Indexed: 01/30/2023]
Abstract
Cue-induced cravings may hinder behavior change efforts such as smoking cessation. Correlation of cue-induced cravings across multiple stimuli would provide evidence for a cue-reactive phenotype that may have implications for behavior change therapies. The purpose of this study was to examine relationships between cue-induced cravings for cigarettes and cue-induced cravings for a highly preferred food (chocolate) in a sample of smokers not subjected to lengthy deprivation for either of these two appetitive outcomes. Adult smokers (N=164) were assessed for chocolate cravings before and after exposure to chocolate cues and cigarette cravings before and after exposure to smoking cues. Consistent with previous reports, cigarette cravings increased significantly post-cue exposure and chocolate cravings increased significantly post-cue exposure (p's<.0001). Consistent with study hypotheses, the magnitude of the increase in chocolate cravings after cue-exposure was significantly related to the increase in post-cue cigarette cravings (r=0.38; p<.0001), and was significantly related to scores on a retrospective, self-report, measure of cue-induced food cravings in daily life. These findings are consistent with the idea of a general "cue-reactive" phenotype that varies across individuals, a conceptualization of risk that may point the way toward improved interventions for a variety of hedonically mediated behaviors with negative health outcomes.
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Affiliation(s)
- Mindi A Styn
- University of Pittsburgh School of Nursing, Department of Health and Community Systems, 3500 Victoria Street, 415 Victoria Building, Pittsburgh, PA, USA.
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254
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Reinhart RMG, Woodman GF. High stakes trigger the use of multiple memories to enhance the control of attention. Cereb Cortex 2013; 24:2022-35. [PMID: 23448876 DOI: 10.1093/cercor/bht057] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We can more precisely tune attention to highly rewarding objects than other objects in our environment, but how our brains do this is unknown. After a few trials of searching for the same object, subjects' electrical brain activity indicated that they handed off the memory representations used to control attention from working memory to long-term memory. However, when a large reward was possible, the neural signature of working memory returned as subjects recruited working memory to supplement the cognitive control afforded by the representations accumulated in long-term memory. The amplitude of this neural signature of working memory predicted the magnitude of the subsequent behavioral reward-based attention effects across tasks and individuals, showing the ubiquity of this cognitive reaction to high-stakes situations.
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Affiliation(s)
- Robert M G Reinhart
- Department of Psychology, Vanderbilt Vision Research Center, Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN, USA
| | - Geoffrey F Woodman
- Department of Psychology, Vanderbilt Vision Research Center, Center for Integrative & Cognitive Neuroscience, Vanderbilt University, Nashville, TN, USA
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255
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Hoch T, Kreitz S, Gaffling S, Pischetsrieder M, Hess A. Manganese-enhanced magnetic resonance imaging for mapping of whole brain activity patterns associated with the intake of snack food in ad libitum fed rats. PLoS One 2013; 8:e55354. [PMID: 23408973 PMCID: PMC3567069 DOI: 10.1371/journal.pone.0055354] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 12/30/2012] [Indexed: 11/26/2022] Open
Abstract
Non-homeostatic hyperphagia, which is a major contributor to obesity-related hyperalimentation, is associated with the diet’s molecular composition influencing, for example, the energy content. Thus, specific food items such as snack food may induce food intake independent from the state of satiety. To elucidate mechanisms how snack food may induce non-homeostatic food intake, it was tested if manganese-enhanced magnetic resonance imaging (MEMRI) was suitable for mapping the whole brain activity related to standard and snack food intake under normal behavioral situation. Application of the MnCl2 solution by osmotic pumps ensured that food intake was not significantly affected by the treatment. After z-score normalization and a non-affine three-dimensional registration to a rat brain atlas, significantly different grey values of 80 predefined brain structures were recorded in ad libitum fed rats after the intake of potato chips compared to standard chow at the group level. Ten of these areas had previously been connected to food intake, in particular to hyperphagia (e.g. dorsomedial hypothalamus or the anterior paraventricular thalamic nucleus) or to the satiety system (e.g. arcuate hypothalamic nucleus or solitary tract); 27 areas were related to reward/addiction including the core and shell of the nucleus accumbens, the ventral pallidum and the ventral striatum (caudate and putamen). Eleven areas associated to sleep displayed significantly reduced Mn2+-accumulation and six areas related to locomotor activity showed significantly increased Mn2+-accumulation after the intake of potato chips. The latter changes were associated with an observed significantly higher locomotor activity. Osmotic pump-assisted MEMRI proved to be a promising technique for functional mapping of whole brain activity patterns associated to nutritional intake under normal behavior.
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Affiliation(s)
- Tobias Hoch
- Department of Chemistry and Pharmacy, Food Chemistry Division, Emil Fischer Center, University of Erlangen-Nuremberg, Erlangen, Germany
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256
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Johnson AW. Eating beyond metabolic need: how environmental cues influence feeding behavior. Trends Neurosci 2013; 36:101-9. [DOI: 10.1016/j.tins.2013.01.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/07/2013] [Indexed: 01/05/2023]
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257
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Serotonin activates catecholamine neurons in the solitary tract nucleus by increasing spontaneous glutamate inputs. J Neurosci 2013; 32:16530-8. [PMID: 23152635 DOI: 10.1523/jneurosci.1372-12.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Serotonin (5-HT) is a critical neurotransmitter in the control of autonomic functions. 5-HT(3) receptors participate in vagal afferent feedback to decrease food intake and regulate cardiovascular reflexes; however, the phenotype of the solitary tract nucleus (NTS) neurons involved is not known. A(2)/C(2) catecholamine (CA) neurons in the NTS are directly activated by visceral afferents and are important for the control of food intake and cardiovascular function, making them good candidates to respond to and mediate the effects of serotonin at the level of the NTS. This study examines serotonin's effects on NTS-CA neurons using patch-clamp techniques and transgenic mice expressing an enhanced green fluorescent protein driven by the tyrosine hydroxylase (TH) promoter (TH-EGFP) to identify catecholamine neurons. Serotonin increased the frequency of spontaneous glutamate excitatory postsynaptic currents (sEPSCs) in >90% of NTS-TH-EGFP neurons, an effect blocked by the 5-HT(3) receptor antagonist ondansetron and mimicked by the 5-HT(3) receptor agonists SR5227 and mCPBG. In contrast, 5-HT(3) receptor agonists increased sEPSCs on a minority (<30%) of non-TH neurons. 5-HT(3) receptor agonists increased the frequency, but not the amplitude, of mini-EPSCs, suggesting that their actions are presynaptic. 5-HT(3) receptor agonists increased the firing rate of TH-EGFP neurons, an effect dependent on the increased spontaneous glutamate inputs as it was blocked by the ionotropic glutamate antagonist NBQX, but independent of visceral afferent activation. These results demonstrate a cellular mechanism by which serotonin activates NTS-TH neurons and suggest a pathway by which it can increase catecholamine release in target regions to modulate food intake, motivation, stress, and cardiovascular function.
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258
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Andresen MC, Fawley JA, Hofmann ME. Peptide and lipid modulation of glutamatergic afferent synaptic transmission in the solitary tract nucleus. Front Neurosci 2013; 6:191. [PMID: 23335875 PMCID: PMC3541483 DOI: 10.3389/fnins.2012.00191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/17/2012] [Indexed: 12/21/2022] Open
Abstract
The brainstem nucleus of the solitary tract (NTS) holds the first central neurons in major homeostatic reflex pathways. These homeostatic reflexes regulate and coordinate multiple organ systems from gastrointestinal to cardiopulmonary functions. The core of many of these pathways arise from cranial visceral afferent neurons that enter the brain as the solitary tract (ST) with more than two-thirds arising from the gastrointestinal system. About one quarter of ST afferents have myelinated axons but the majority are classed as unmyelinated C-fibers. All ST afferents release the fast neurotransmitter glutamate with remarkably similar, high-probability release characteristics. Second order NTS neurons receive surprisingly limited primary afferent information with one or two individual inputs converging on single second order NTS neurons. A- and C-fiber afferents never mix at NTS second order neurons. Many transmitters modify the basic glutamatergic excitatory postsynaptic current often by reducing glutamate release or interrupting terminal depolarization. Thus, a distinguishing feature of ST transmission is presynaptic expression of G-protein coupled receptors for peptides common to peripheral or forebrain (e.g., hypothalamus) neuron sources. Presynaptic receptors for angiotensin (AT1), vasopressin (V1a), oxytocin, opioid (MOR), ghrelin (GHSR1), and cholecystokinin differentially control glutamate release on particular subsets of neurons with most other ST afferents unaffected. Lastly, lipid-like signals are transduced by two key ST presynaptic receptors, the transient receptor potential vanilloid type 1 and the cannabinoid receptor that oppositely control glutamate release. Increasing evidence suggests that peripheral nervous signaling mechanisms are repurposed at central terminals to control excitation and are major sites of signal integration of peripheral and central inputs particularly from the hypothalamus.
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Affiliation(s)
- Michael C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University Portland, OR, USA
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259
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Alexandrov YI, Grinchenko YV, Shevchenko DG, Averkin RG, Matz VN, Laukka S, Sams M. The Effect of Ethanol on the Neuronal Subserving of Behavior in the Hippocampus. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jbbs.2013.31011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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260
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Picciotto MR, Kenny PJ. Molecular mechanisms underlying behaviors related to nicotine addiction. Cold Spring Harb Perspect Med 2013; 3:a012112. [PMID: 23143843 DOI: 10.1101/cshperspect.a012112] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tobacco smoking results in more than 5 million deaths each year and accounts for almost 90% of all deaths from lung cancer. Nicotine, the major reinforcing component of tobacco smoke, acts in the brain through the neuronal nicotinic acetylcholine receptors (nAChRs). The nAChRs are allosterically regulated, ligand-gated ion channels consisting of five membrane-spanning subunits. Twelve mammalian α subunits (α2-α10) and β subunits (β2-β4) have been cloned. The predominant nAChR subtypes in mammalian brain are those containing α4 and β2 subunits (denoted as α4β2* nAChRs). The α4β2* nAChRs mediate many behaviors related to nicotine addiction and are the primary targets for currently approved smoking cessation agents. Considering the large number of nAChR subunits in the brain, it is likely that nAChRs containing subunits in addition to α4 and β2 also play a role in tobacco smoking. Indeed, genetic variation in the CHRNA5-CHRNA3-CHRNB4 gene cluster, encoding the α5, α3, and β4 nAChR subunits, respectively, has been shown to increase vulnerability to tobacco dependence and smoking-associated diseases including lung cancer. Moreover, mice in which expression of α5 or β4 subunits has been genetically modified have profoundly altered patterns of nicotine consumption. In addition to the reinforcing properties of nicotine, the effects of nicotine on appetite, attention, and mood are also thought to contribute to establishment and maintenance of the tobacco smoking habit. Here we review recent insights into the behavioral actions of nicotine and the nAChRs subtypes involved, which likely contribute to the development of tobacco dependence in smokers.
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Affiliation(s)
- Marina R Picciotto
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508, USA.
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261
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High-fat diet alters the dopamine and opioid systems: effects across development. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2012; 2:S25-8. [PMID: 27152150 DOI: 10.1038/ijosup.2012.18] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Consumption of a high-fat diet has been linked to obesity, dyslipidemia and cardiovascular disease. Less well appreciated are adverse effects on the brain and behavior. Recent research has shown that consumption of a high-fat diet can alter gene expression within the brain, and the dopamine and opioid neurotransmitter systems appear to be vulnerable to dysregulation. This review will focus on recent reports in both humans and animal models that describe adverse effects of high-fat diet consumption on the central reward circuitry. In addition, the importance of different development windows will be discussed, with effects observed in both the prenatal/perinatal time period and with chronic high-fat diet consumption in adulthood.
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262
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Mueller K, Sacher J, Arelin K, Holiga Š, Kratzsch J, Villringer A, Schroeter ML. Overweight and obesity are associated with neuronal injury in the human cerebellum and hippocampus in young adults: a combined MRI, serum marker and gene expression study. Transl Psychiatry 2012; 2:e200. [PMID: 23212584 PMCID: PMC3565188 DOI: 10.1038/tp.2012.121] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
There is growing evidence that obesity represents a risk for enhanced gray matter (GM) density changes comparable to those demonstrated for mild cognitive impairment in the elderly. However, it is not clear what mechanisms underlie this apparent alteration in brain structure of overweight subjects and to what extent these changes can already occur in the adolescent human brain. In the present volumetric magnetic resonance imaging study, we investigated GM changes and serum levels of neuron-specific enolase (NSE), a marker for neuronal injury, in a set of overweight/obese subjects and controls. We report a negative correlation for overweight and obese subjects between serum NSE and GM density in hippocampal and cerebellar regions. To validate our neuroimaging findings, we complement these data with NSE gene expression information obtained from the Allen Brain atlas. GM density changes were localized in brain areas that mediate cognitive function-the hippocampus associated with memory performance, and the cognitive cerebellum (lateral posterior lobes) associated with executive, spatial and linguistic processing. The data of our present study highlight the importance of extending current research on cognitive function and brain plasticity in the elderly in the context of obesity to young adult subjects and include serum biomarkers to validate imaging findings generally.
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Affiliation(s)
- K Mueller
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - J Sacher
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany,Clinic of Cognitive Neurology, University of Leipzig, Leipzig, Germany
| | - K Arelin
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany,Clinic of Cognitive Neurology, University of Leipzig, Leipzig, Germany,Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany
| | - Š Holiga
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - J Kratzsch
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University of Leipzig, Leipzig, Germany
| | - A Villringer
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany,Clinic of Cognitive Neurology, University of Leipzig, Leipzig, Germany,Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany
| | - M L Schroeter
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany,Clinic of Cognitive Neurology, University of Leipzig, Leipzig, Germany,Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany,Consortium for Frontotemporal Lobar Degeneration, Ulm, Germany
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263
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Diet-induced obesity: dopamine transporter function, impulsivity and motivation. Int J Obes (Lond) 2012; 37:1095-103. [PMID: 23164701 DOI: 10.1038/ijo.2012.178] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/26/2012] [Accepted: 10/06/2012] [Indexed: 12/28/2022]
Abstract
OBJECTIVE A rat model of diet-induced obesity (DIO) was used to determine dopamine transporter (DAT) function, impulsivity and motivation as neurobehavioral outcomes and predictors of obesity. DESIGN To evaluate neurobehavioral alterations following the development of DIO induced by an 8-week high-fat diet (HF) exposure, striatal D2-receptor density, DAT function and expression, extracellular dopamine concentrations, impulsivity, and motivation for high- and low-fat reinforcers were determined. To determine predictors of DIO, neurobehavioral antecedents including impulsivity, motivation for high-fat reinforcers, DAT function and extracellular dopamine were evaluated before the 8-week HF exposure. METHODS Striatal D2-receptor density was determined by in vitro kinetic analysis of [(3)H]raclopride binding. DAT function was determined using in vitro kinetic analysis of [(3)H]dopamine uptake, methamphetamine-evoked [(3)H]dopamine overflow and no-net flux in vivo microdialysis. DAT cell-surface expression was determined using biotinylation and western blotting. Impulsivity and food-motivated behavior were determined using a delay discounting task and progressive ratio schedule, respectively. RESULTS Relative to obesity-resistant (OR) rats, obesity-prone (OP) rats exhibited 18% greater body weight following an 8-week HF-diet exposure, 42% lower striatal D2-receptor density, 30% lower total DAT expression, 40% lower in vitro and in vivo DAT function, 45% greater extracellular dopamine and twofold greater methamphetamine-evoked [(3)H]dopamine overflow. OP rats exhibited higher motivation for food, and surprisingly, were less impulsive relative to OR rats. Impulsivity, in vivo DAT function and extracellular dopamine concentration did not predict DIO. Importantly, motivation for high-fat reinforcers predicted the development of DIO. CONCLUSION Human studies are limited by their ability to determine if impulsivity, motivation and DAT function are causes or consequences of DIO. The current animal model shows that motivation for high-fat food, but not impulsive behavior, predicts the development of obesity, whereas decreases in striatal DAT function are exhibited only after the development of obesity.
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264
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Multilocus genetic composite reflecting dopamine signaling capacity predicts reward circuitry responsivity. J Neurosci 2012; 32:10093-100. [PMID: 22815523 DOI: 10.1523/jneurosci.1506-12.2012] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The objective of the study was to test the hypotheses that humans with genotypes putatively associated with low dopamine (DA) signaling capacity, including the TaqIA A1 allele, DRD2-141C Ins/Ins genotype, DRD4 7-repeat or longer allele, DAT1 10-repeat allele, and the Met/Met COMT genotype, and with a greater number of these genotypes per a multilocus composite, show less responsivity of reward regions that primarily rely on DA signaling. Functional magnetic resonance imaging (fMRI) paradigms were used to investigate activation in response to receipt and anticipated receipt of palatable food and monetary reward. DNA was extracted from saliva using standard methods. Participants were 160 adolescents (mean age = 15.3 years, SD = 1.07 years; mean body mass index = 20.8, SD = 1.9). The main outcome was blood oxygenation level-dependent activation in the fMRI paradigms. Data confirmed that these fMRI paradigms activated reward, attention, somatosensory, and gustatory regions. Individuals with, versus without, these five genotypes did not show less activation of DA-based reward regions, but those with the Met/Met versus the Val/Val COMT genotype showed less middle temporal gyrus activation and those with the DRD4-L versus the DRD4-S genotype showed less middle occipital gyrus activation in response to monetary reward. Critically, the multilocus composite score revealed that those with a greater number of these genotypes showed less activation in reward regions, including the putamen, caudate, and insula, in response to monetary reward. The results suggest that the multilocus genetic composite is a more sensitive index of vulnerability for low reward region responsivity than individual genotypes.
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265
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McCutcheon JE, Ebner SR, Loriaux AL, Roitman MF. Encoding of aversion by dopamine and the nucleus accumbens. Front Neurosci 2012; 6:137. [PMID: 23055953 PMCID: PMC3457027 DOI: 10.3389/fnins.2012.00137] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/04/2012] [Indexed: 11/13/2022] Open
Abstract
Adaptive motivated behavior requires rapid discrimination between beneficial and harmful stimuli. Such discrimination leads to the generation of either an approach or rejection response, as appropriate, and enables organisms to maximize reward and minimize punishment. Classically, the nucleus accumbens (NAc) and the dopamine projection to it are considered an integral part of the brain's reward circuit, i.e., they direct approach and consumption behaviors and underlie positive reinforcement. This reward-centered framing ignores important evidence about the role of this system in encoding aversive events. One reason for bias toward reward is the difficulty in designing experiments in which animals repeatedly experience punishments; another is the challenge in dissociating the response to an aversive stimulus itself from the reward/relief experienced when an aversive stimulus is terminated. Here, we review studies that employ techniques with sufficient time resolution to measure responses in ventral tegmental area and NAc to aversive stimuli as they are delivered. We also present novel findings showing that the same stimulus - intra-oral infusion of sucrose - has differing effects on NAc shell dopamine release depending on the prior experience. Here, for some rats, sucrose was rendered aversive by explicitly pairing it with malaise in a conditioned taste aversion paradigm. Thereafter, sucrose infusions led to a suppression of dopamine with a similar magnitude and time course to intra-oral infusions of a bitter quinine solution. The results are discussed in the context of regional differences in dopamine signaling and the implications of a pause in phasic dopamine release within the NAc shell. Together with our data, the emerging literature suggests an important role for differential phasic dopamine signaling in aversion vs. reward.
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Affiliation(s)
- James E McCutcheon
- Department of Psychology, University of Illinois at Chicago Chicago, IL, USA
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266
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The drive to eat: comparisons and distinctions between mechanisms of food reward and drug addiction. Nat Neurosci 2012; 15:1330-5. [PMID: 23007187 DOI: 10.1038/nn.3202] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The growing rates of obesity have prompted comparisons between the uncontrolled intake of food and drugs; however, an evaluation of the equivalence of food- and drug-related behaviors requires a thorough understanding of the underlying neural circuits driving each behavior. Although it has been attractive to borrow neurobiological concepts from addiction to explore compulsive food seeking, a more integrated model is needed to understand how food and drugs differ in their ability to drive behavior. In this Review, we will examine the commonalities and differences in the systems-level and behavioral responses to food and to drugs of abuse, with the goal of identifying areas of research that would address gaps in our understanding and ultimately identify new treatments for obesity or drug addiction.
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267
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Abstract
INTRODUCTION The ability of nicotine, the primary psychoactive substance in tobacco smoke, to regulate appetite and body weight is one of the factors cited by smokers that prevents them from quitting and is the primary reason for smoking initiation in teenage girls. The regulation of feeding and metabolism by nicotine is complex, and recent studies have begun to identify nicotinic acetylcholine receptor (nAChR) subtypes and circuits or cell types involved in this regulation. DISCUSSION We will briefly describe the primary anatomical and functional features of the input, output, and central integration structures of the neuroendocrine systems that regulate energy homeostasis. Then, we will describe the nAChR subtypes expressed in these structures in mammals to identify the possible molecular targets for nicotine. Finally, we will review the effects of nicotine and its withdrawal on feeding and energy metabolism and attribute them to potential central and peripheral cellular targets.
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Affiliation(s)
- Michele Zoli
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125, Modena, Italy.
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268
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Grill HJ, Hayes MR. Hindbrain neurons as an essential hub in the neuroanatomically distributed control of energy balance. Cell Metab 2012; 16:296-309. [PMID: 22902836 PMCID: PMC4862653 DOI: 10.1016/j.cmet.2012.06.015] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 03/20/2012] [Accepted: 06/08/2012] [Indexed: 02/07/2023]
Abstract
This Review highlights the processing and integration performed by hindbrain nuclei, focusing on the inputs received by nucleus tractus solitarius (NTS) neurons. These inputs include vagally mediated gastrointestinal satiation signals, blood-borne energy-related hormonal and nutrient signals, and descending neural signals from the forebrain. We propose that NTS (and hindbrain neurons, more broadly) integrate these multiple energy status signals and issue-output commands controlling the behavioral, autonomic, and endocrine responses that collectively govern energy balance. These hindbrain-mediated controls are neuroanatomically distributed; they involve endemic hindbrain neurons and circuits, hindbrain projections to peripheral circuits, and projections to and from midbrain and forebrain nuclei.
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Affiliation(s)
- Harvey J Grill
- Graduate Group of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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269
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Medial prefrontal cortex neuronal activation and synaptic alterations after stress-induced reinstatement of palatable food seeking: a study using c-fos-GFP transgenic female rats. J Neurosci 2012; 32:8480-90. [PMID: 22723688 DOI: 10.1523/jneurosci.5895-11.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Relapse to maladaptive eating habits during dieting is often provoked by stress and there is evidence for a role of ovarian hormones in stress responses and feeding. We studied the role of these hormones in stress-induced reinstatement of food seeking and medial prefrontal cortex (mPFC) neuronal activation in c-fos-GFP transgenic female rats, which express GFP in strongly activated neurons. Food-restricted ovariectomized or sham-operated c-fos-GFP rats were trained to lever-press for palatable food pellets. Subsequently, lever-pressing was extinguished and reinstatement of food seeking and mPFC neuronal activation was assessed after injections of the pharmacological stressor yohimbine (0.5-2 mg/kg) or pellet priming (1-4 noncontingent pellets). Estrous cycle effects on reinstatement were also assessed in wild-type rats. Yohimbine- and pellet-priming-induced reinstatement was associated with Fos and GFP induction in mPFC; both reinstatement and neuronal activation were minimally affected by ovarian hormones in both c-fos-GFP and wild-type rats. c-fos-GFP transgenic rats were then used to assess glutamatergic synaptic alterations within activated GFP-positive and nonactivated GFP-negative mPFC neurons following yohimbine-induced reinstatement of food seeking. This reinstatement was associated with reduced AMPA receptor/NMDA receptor current ratios and increased paired-pulse facilitation in activated GFP-positive but not GFP-negative neurons. While ovarian hormones do not appear to play a role in stress-induced relapse of food seeking in our rat model, this reinstatement was associated with unique synaptic alterations in strongly activated mPFC neurons. Our paper introduces the c-fos-GFP transgenic rat as a new tool to study unique synaptic changes in activated neurons during behavior.
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270
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Stuber GD. Food for thought: attenuation of dopamine signaling by insulin (commentary on Mebel et al.). Eur J Neurosci 2012; 36:2335. [PMID: 22861129 DOI: 10.1111/j.1460-9568.2012.08214.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Garret D Stuber
- Departments of Psychiatry & Cell and Molecular Physiology, UNC Neuroscience Center, Campus Box 7250, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7250, USA
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271
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Abstract
Binge eating disorder (BED) is the most prevalent eating disorder in adults, and individuals with BED report greater general and specific psychopathology than non-eating disordered individuals. The current paper reviews research on psychological treatments for BED, including the rationale and empirical support for cognitive behavioral therapy (CBT), interpersonal psychotherapy (IPT), dialectical behavior therapy (DBT), behavioral weight loss (BWL), and other treatments warranting further study. Research supports the effectiveness of CBT and IPT for the treatment of BED, particularly for those with higher eating disorder and general psychopathology. Guided self-help CBT has shown efficacy for BED without additional pathology. DBT has shown some promise as a treatment for BED, but requires further study to determine its long-term efficacy. Predictors and moderators of treatment response, such as weight and shape concerns, are highlighted and a stepped-care model proposed. Future directions include expanding the adoption of efficacious treatments in clinical practice, testing adapted treatments in diverse samples (e.g., minorities and youth), improving treatment outcomes for nonresponders, and developing efficient and cost-effective stepped-care models.
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Affiliation(s)
- Juliette M. Iacovino
- Department of Psychology, Washington University in St. Louis, Campus Box 1125, One Brookings Drive, St. Louis, MO 63130, USA,
| | - Dana M. Gredysa
- Department of Psychology, Washington University in St. Louis, Campus Box 1125, One Brookings Drive, St. Louis, MO 63130, USA
| | - Myra Altman
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660S Euclid, St. Louis, MO 63110, USA
| | - Denise E. Wilfley
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660S Euclid, St. Louis, MO 63110, USA
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272
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Piccoli L, Micioni Di Bonaventura MV, Cifani C, Costantini VJA, Massagrande M, Montanari D, Martinelli P, Antolini M, Ciccocioppo R, Massi M, Merlo-Pich E, Di Fabio R, Corsi M. Role of orexin-1 receptor mechanisms on compulsive food consumption in a model of binge eating in female rats. Neuropsychopharmacology 2012; 37:1999-2011. [PMID: 22569505 PMCID: PMC3398727 DOI: 10.1038/npp.2012.48] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Orexins (OX) and their receptors (OXR) modulate feeding, arousal, stress, and drug abuse. Neural systems that motivate and reinforce drug abuse may also underlie compulsive food seeking and intake. Therefore, the effects of GSK1059865 (5-bromo-N-[(2S,5S)-1-(3-fluoro-2-methoxybenzoyl)-5-methylpiperidin-2-yl]methyl-pyridin-2-amine), a selective OX(1)R antagonist, JNJ-10397049 (N-(2,4-dibromophenyl)-N'-[(4S,5S)-2,2-dimethyl-4-phenyl-1,3-dioxan-5-yl]urea), a selective OX(2)R antagonist, and SB-649868 (N-[((2S)-1-{[5-(4-fluorophenyl)-2-methyl-1,3-thiazol-4-yl]carbonyl}-2-piperidinyl)methyl]-1-benzofuran-4-carboxamide), a dual OX(1)/OX(2)R antagonist were evaluated in a binge eating (BE) model in female rats. BE of highly palatable food (HPF) was evoked by three cycles of food restriction followed by stress, elicited by exposing rats to HPF, but preventing them from having access to it for 15 min. Pharmacokinetic assessments of all compounds were obtained under the same experimental conditions used for the behavioral experiments. Topiramate was used as the reference compound as it selectively blocks BE in rats and humans. Dose-related thresholds for sleep-inducing effects of the OXR antagonists were measured using polysomnography in parallel experiments. SB-649868 and GSK1059865, but not JNJ-10397049, selectively reduced BE for HPF without affecting standard food pellet intake, at doses that did not induce sleep. These results indicate, for the first time, a major role of OX(1)R mechanisms in BE, suggesting that selective antagonism at OX(1)R could represent a novel pharmacological treatment for BE and possibly other eating disorders with a compulsive component.
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Affiliation(s)
- Laura Piccoli
- GlaxoSmithKline, Medicines Research Centre, Verona, Italy
| | - Maria Vittoria Micioni Di Bonaventura
- Pharmacology Unit, School of Pharmacy, University of Camerino, Macerata, Italy,Pharmacology Unit, School of Pharmacy, University of Camerino, via Madonna delle Carceri, 9, Camerino, Macerata 62032, Italy, Tel: +39 3287041244, Fax: +39 0737403325, E-mail:
| | - Carlo Cifani
- Pharmacology Unit, School of Pharmacy, University of Camerino, Macerata, Italy
| | | | | | - Dino Montanari
- GlaxoSmithKline, Medicines Research Centre, Verona, Italy
| | | | | | - Roberto Ciccocioppo
- Pharmacology Unit, School of Pharmacy, University of Camerino, Macerata, Italy
| | - Maurizio Massi
- Pharmacology Unit, School of Pharmacy, University of Camerino, Macerata, Italy
| | - Emilio Merlo-Pich
- Neuronal Target Discovery Performance Unit, GlaxoSmithKline, King of Prussia, PA, USA
| | | | - Mauro Corsi
- GlaxoSmithKline, Medicines Research Centre, Verona, Italy
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273
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Kaidanovich-Beilin O, Cha DS, McIntyre RS. Crosstalk between metabolic and neuropsychiatric disorders. F1000 BIOLOGY REPORTS 2012; 4:14. [PMID: 22802875 PMCID: PMC3388805 DOI: 10.3410/b4-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Evidence supporting the concurrence of metabolic disturbances (e.g. insulin resistance, diabetes and obesity) and neuropsychiatric disorders has been demonstrated in both human and animal studies, suggesting the possibility that they have shared pathophysiological mechanisms. During the past decade, our understanding for the role of insulin in both normal and abnormal central nervous system (CNS) processes has become increasingly refined. Evidence indicates that insulin is a pleiotropic peptide, critical to neurotrophism, neuroplasticity, and neuromodulation. Moreover, the role of insulin underscores its importance in the development of several neuropsychiatric disorders, including, but not limited to, mechanisms involved in the pathogenesis and progression towards diabetes, obesity, and neurodegenerative disorders, such as Alzheimer's disease. This review focuses on the insulin-mediated effects on normal and abnormal brain function and discusses why targeting insulin-related pathways in the brain may emerge as a new approach for refining treatment of neurological and psychiatric disorders.
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Affiliation(s)
- Oksana Kaidanovich-Beilin
- Samuel Lunenfeld Research InstituteMount Sinai Hospital, 600 University Avenue, Room 983, Toronto, Ontario, M5G 1X5Canada
| | - Danielle S. Cha
- Department of Psychiatry, University of Toronto, and the Mood Disorders Psychopharmacology Unit, University Health Network399 Bathurst Street, MP 9-325, Toronto, Ontario, M5T 2S8Canada
| | - Roger S. McIntyre
- Department of Psychiatry, University of Toronto, and the Mood Disorders Psychopharmacology Unit, University Health Network399 Bathurst Street, MP 9-325, Toronto, Ontario, M5T 2S8Canada
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274
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275
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Schellekens H, Finger BC, Dinan TG, Cryan JF. Ghrelin signalling and obesity: at the interface of stress, mood and food reward. Pharmacol Ther 2012; 135:316-26. [PMID: 22749794 DOI: 10.1016/j.pharmthera.2012.06.004] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 12/14/2022]
Abstract
The neuronal circuitry underlying the complex relationship between stress, mood and food intake are slowly being unravelled and several studies suggest a key role herein for the peripherally derived hormone, ghrelin. Evidence is accumulating linking obesity as an environmental risk factor to psychiatric disorders such as stress, anxiety and depression. Ghrelin is the only known orexigenic hormone from the periphery to stimulate food intake. Plasma ghrelin levels are enhanced under conditions of physiological stress and ghrelin has recently been suggested to play an important role in stress-induced food reward behaviour. In addition, chronic stress or atypical depression has often demonstrated to correlate with an increase in ingestion of caloric dense 'comfort foods' and have been implicated as one of the major contributor to the increased prevalence of obesity. Recent evidence suggests ghrelin as a critical factor at the interface of homeostatic control of appetite and reward circuitries, modulating the hedonic aspects of food intake. Therefore, the reward-related feeding of ghrelin may reveal itself as an important factor in the development of addiction to certain foods, similar to its involvement in the dependence to drugs of abuse, including alcohol. This review will highlight the accumulating evidence demonstrating the close interaction between food, mood and stress and the development of obesity. We consider the ghrelinergic system as an effective target for the development of successful anti-obesity pharmacotherapies, which not only affects appetite but also selectively modulates the rewarding properties of food and impact on psychological well-being in conditions of stress, anxiety and depression.
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276
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Tossing the baby out with the bathwater after a brief rinse? The potential downside of dismissing food addiction based on limited data. Nat Rev Neurosci 2012; 13:514; author reply 514. [PMID: 22714023 DOI: 10.1038/nrn3212-c1] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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277
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Erreger K, Davis AR, Poe AM, Greig NH, Stanwood GD, Galli A. Exendin-4 decreases amphetamine-induced locomotor activity. Physiol Behav 2012; 106:574-8. [PMID: 22465309 DOI: 10.1016/j.physbeh.2012.03.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 03/09/2012] [Accepted: 03/12/2012] [Indexed: 12/21/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is released in response to nutrient ingestion and is a regulator of energy metabolism and consummatory behaviors through both peripheral and central mechanisms. The GLP-1 receptor (GLP-1R) is widely distributed in the central nervous system, however little is known about how GLP-1Rs regulate ambulatory behavior. The abused psychostimulant amphetamine (AMPH) promotes behavioral locomotor activity primarily by inducing the release of the neurotransmitter dopamine. Here, we identify the GLP-1R agonist exendin-4 (Ex-4) as a modulator of behavioral activation by AMPH. We report that in rats a single acute administration of Ex-4 decreases both basal locomotor activity as well as AMPH-induced locomotor activity. Ex-4 did not induce behavioral responses reflecting anxiety or aversion. Our findings implicate GLP-1R signaling as a novel modulator of psychostimulant-induced behavior and therefore a potential therapeutic target for psychostimulant abuse.
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Affiliation(s)
- Kevin Erreger
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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278
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Li N, Tian ZB, Sun GR, Wei LZ, Xu L, Wang BH, Kong XJ, Ding XL, Cui MJ. Effect of Nesfatin-1 on gastric emptying and contraction of gastric smooth muscle strips in obese rats. Shijie Huaren Xiaohua Zazhi 2012; 20:631-637. [DOI: 10.11569/wcjd.v20.i8.631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To observe the impact of treatment with Nesfatin-1 on gastric emptying and stomach smooth muscle contraction in obese rats.
METHODS: Obese rats were fed a high-nutrition diet for 6 weeks, while control rats were fed a normal diet. Different concentrations of Nesfatin-1 (0.5, 5, 50 μmol/L) were injected into the dorsal vagal complex (DVC). Gastric emptying was then determined, and the spontaneous contraction of isolated circular smooth muscle of gastric fundus and gastric body was recorded. In addition, the impact of different concentrations of Nesfatin-1 (0.026, 0.26, 2.6 μmol/L) on acetylcholine (Ach)-induced muscle contraction was observed.
RESULTS: Various concentrations of Nesfatin-1 significantly inhibited the contraction of gastric smooth muscle strips isolated from both normal and obese rats compared to rats treated with normal saline (q = 3.93-15.72, all P < 0.05 or 0.01). Compared to normal rats, low-concentration Nesfatin-1 showed no significant relaxing effect on stomach fundus smooth muscle in obese rats (P > 0.05); however, medium and high concentrations of Nesfatin-1 significantly inhibited the contraction of gastric fundus smooth muscle of obese rats (t = 2.14, 2.63; both P < 0.05). Compared to normal rats, low and medium concentrations of Nesfatin-1 showed no significant relaxing effect on stomach corpus smooth muscle in obese rats (both P > 0.05); however, high-concentration Nesfatin-1 significantly inhibited the contraction of gastric corpus smooth muscle of obese rats (t = 2.53, P < 0.05).
CONCLUSION: Nesfatin-1 inhibits gastric emptying in normal and obese rats and acetylcholine-induced gastric smooth muscle contraction in obese rats in a concentration-dependent manner. The inhibitory effect of Nesfatin-1 is stronger in normal rats than in obese ones.
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279
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Ziauddeen H, Farooqi IS, Fletcher PC. Obesity and the brain: how convincing is the addiction model? Nat Rev Neurosci 2012; 13:279-86. [PMID: 22414944 DOI: 10.1038/nrn3212] [Citation(s) in RCA: 268] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An increasingly influential perspective conceptualizes both obesity and overeating as a food addiction accompanied by corresponding brain changes. Because there are far-reaching implications for clinical practice and social policy if it becomes widely accepted, a critical evaluation of this model is important. We examine the current evidence for the link between addiction and obesity, identifying several fundamental shortcomings in the model, as well as weaknesses and inconsistencies in the empirical support for it from human neuroscientific research.
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Affiliation(s)
- Hisham Ziauddeen
- Department of Psychiatry, University of Cambridge, Herchel Smith Building, Addenbrooke's Hospital, Cambridge CB2 0SZ, UK
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280
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Janero DR. Cannabinoid-1 receptor (CB1R) blockers as medicines: beyond obesity and cardiometabolic disorders to substance abuse/drug addiction with CB1R neutral antagonists. Expert Opin Emerg Drugs 2012; 17:17-29. [DOI: 10.1517/14728214.2012.660916] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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