| 1. |
- Alsiö, Johan, et al.
(författare)
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Dopamine D1 receptor gene expression decreases in the nucleus accumbens upon long-term exposure to palatable food and differs depending on diet-induced obesity phenotype in rats
- 2010
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 171:3, s. 779-787
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Tidskriftsartikel (refereegranskat)abstract
- The nucleus accumbens (NAcc) mediates feeding reward; its activity reflects tastants' hedonic value. NAcc dopamine guides immediate responses to reward, however, its involvement in establishing long-term responses after a period of exposure to palatable foods has not been defined. Furthermore, reward-driven overeating propels weight increase, but the scale of weight gain depends on animals' obesity-prone (OP) or -resistant (OR) phenotype. It is unclear whether the NAcc dopamine response to palatable food depends on obesity susceptibility. We investigated the effect of unrestricted extended access to high-fat high-sugar (HFHS) diet on expression of genes encoding dopamine receptors in the NAcc of OP and OR rats. We examined persistence of HFHS diet-induced changes in D(1) and D(2) gene expression in OP and OR rats subjected to HFHS withdrawal (bland chow for 18 days). Effects of restricted access to HFHS by pair-feeding were also studied. Using reverse transcriptase PCR (RT-PCR), we found that NAcc D(1) mRNA was downregulated after long-term HFHS access in OP vs. OR animals. The effect was also observed after 18 days of HFHS withdrawal. Furthermore, restricted HFHS led to downregulation of D(1) as well as of D(2) mRNA levels compared to chow-fed controls. A difference in the expression of mu opioid receptor in the NAcc was also detected between the OP and OR rats during access to palatable food but not after withdrawal. We conclude that exposure to HFHS diets has lasting consequences for the NAcc dopamine system, perhaps modifying the motivation to search for food reward. The fact that the NAcc D(1) expression changes in OP animals after long-term exposure to palatable food and that this effect extends well into the reward discontinuation phase, implicates the D(1) receptor in the propensity to overeat and, in effect, gain weight in obesity prone individuals.
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| 2. |
- Benedict, Christian, et al.
(författare)
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Acute sleep deprivation reduces energy expenditure in healthy men
- 2011
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 93:6, s. 1229-1236
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundEpidemiologic evidence indicates that chronic sleep curtailment increases risk of developing obesity, but the mechanisms behind this relation are largely unknown.ObjectiveWe examined the influence of a single night of total sleep deprivation on morning energy expenditures and food intakes in healthy humans.DesignAccording to a balanced crossover design, we examined 14 normal-weight male subjects on 2 occasions during a regular 24-h sleep-wake cycle (including 8 h of nocturnal sleep) and a 24-h period of continuous wakefulness. On the morning after regular sleep and total sleep deprivation, resting and postprandial energy expenditures were assessed by indirect calorimetry, and the free-choice food intake from an opulent buffet was tested in the late afternoon at the end of the experiment. Circulating concentrations of ghrelin, leptin, norepinephrine, cortisol, thyreotropin, glucose, and insulin were repeatedly measured over the entire 24-h session.ResultsIn comparison with normal sleep, resting and postprandial energy expenditures assessed on the subsequent morning were significantly reduced after sleep deprivation by approximate to 5% and 20%, respectively (P < 0.05 and P < 0.0001). Nocturnal wakefulness increased morning plasma ghrelin concentrations (P < 0.02) and nocturnal and daytime circulating concentrations of thyreotropin, cortisol, and norepinephrine (P < 0.05) as well as morning postprandial plasma glucose concentrations (P < 0.05). Changes in food intakes were variable, and no differences between wake and sleep conditions were detected.ConclusionOur findings show that one night of sleep deprivation acutely reduces energy expenditure in healthy men, which suggests that sleep contributes to the acute regulation of daytime energy expenditure in humans.
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| 3. |
- Brooks, Samantha Jane, et al.
(författare)
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A debate on current eating disorder diagnoses in light of neurobiological findings : is it time for a spectrum model?
- 2012
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Ingår i: BMC Psychiatry. - 1471-244X. ; 12, s. 76-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sixty percent of eating disorders do not meet criteria for anorexia- or bulimia nervosa, as defined by the Diagnostic and Statistical Manual version 4 (DSM-IV). Instead they are diagnosed as 'eating disorders not otherwise specified' (EDNOS). Discrepancies between criteria and clinical reality currently hampering eating disorder diagnoses in the DSM-IV will be addressed by the forthcoming DSM-V. However, future diagnoses for eating disorders will rely on current advances in the fields of neuroimaging and genetics for classification of symptoms that will ultimately improve treatment. Discussion: Here we debate the classification issues, and discuss how brain imaging and genetic discoveries might be interwoven into a model of eating disorders to provide better classification and treatment. The debate concerns: a) current issues in the classification of eating disorders in the DSM-IV, b) changes proposed for DSM-V, c) neuroimaging eating disorder research and d) genetic eating disorder research. Summary: We outline a novel evidence-based 'impulse control' spectrum model of eating disorders. A model of eating disorders is proposed that will aid future diagnosis of symptoms, coinciding with contemporary suggestions by clinicians and the proposed changes due to be published in the DSM-V.
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| 4. |
- Chapman, Colin Daniel, et al.
(författare)
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Lifestyle determinants of the drive to eat : a meta-analysis
- 2012
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 96:3, s. 492-497
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Tidskriftsartikel (refereegranskat)abstract
- Background: Obesity is emerging as the most significant health concern of the 21st century. Although this is attributable in part to changes in our environment-including the increased prevalence of energy-dense food-it also appears that several lifestyle factors may increase our vulnerability to this calorie-rich landscape. Epidemiologic studies have begun to show links between adiposity and behaviors such as television watching, alcohol intake, and sleep deprivation. However, these studies leave unclear the direction of this association. In addition, studies that investigated the acute impact of these factors on food intake have reported a wide variety of effect sizes, from highly positive to slightly negative.Objective: The purpose of this article was to provide a meta-analysis of the relation between lifestyle choices and increases in acute food intake.Design: An initial search was performed on PubMed to collect articles relating television watching, sleep deprivation, and alcohol consumption to food intake. Only articles published before February 2012 were considered. Studies that took place in a controlled, laboratory setting with healthy individuals were included. Studies were analyzed by using 3 meta-analyses with random-effects models. In addition, a 1-factor ANOVA was run to discover any main effect of lifestyle.Results: The 3 most prominent lifestyle factors-television watching, alcohol intake, and sleep deprivation-had significant short-term effects on food intake, with alcohol being more significant (Cohen's d = 1.03) than sleep deprivation (Cohen's d = 0.49) and television watching (Cohen's d = 0.2).Conclusions: Our results suggest that television watching, alcohol intake, and sleep deprivation are not merely correlated with obesity but likely contribute to it by encouraging excessive eating. Because these behaviors are all known to affect cognitive functions involved in reward saliency and inhibitory control, it may be that they represent common mechanisms through which this eating is facilitated.
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| 5. |
- Gonzalez, Patricia Verónica, et al.
(författare)
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Interleukin-1 beta-induced anorexia is reversed by ghrelin
- 2006
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 27:12, s. 3220-3225
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Tidskriftsartikel (refereegranskat)abstract
- Interleukins, in particular interleukin-1β (IL-1β), reduce food intake after peripheral and central administration, which suggests that they contribute to anorexia during various infectious, neoplastic, and autoimmune diseases. On the other hand, ghrelin stimulates food intake by acting on the central nervous system (CNS) and is considered an important regulator of food intake in both rodents and humans. In the present study, we investigated if ghrelin could reverse IL-1β-induced anorexia. Intracerebroventricular (i.c.v.) injection of 15, 30 or 45 ng/μl of IL-1β caused significant suppression of food intake in 20 h fasting animals. This effect lasted for a 24 h period. Ghrelin (0.15 nmol or 1.5 nmol/μl) produced a significant increase in cumulative food intake in normally fed animals. However, it did not alter food intake in 20 h fasting animals. Central administration of ghrelin reduced the anorexic effect of IL-1β (15 ng/μl). The effect was observed 30 min after injection and lasted for the next 24 h. This study provides evidence that ghrelin is an orexigenic peptide capable of antagonizing IL-1β-induced anorexia.
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| 6. |
- Gonzalez, Patricia Verónica, et al.
(författare)
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Memory impairment induced by IL-1beta is reversed by alpha-MSH through central melanocortin-4 receptors
- 2009
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 23:6, s. 817-822
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-1beta (IL-1beta) significantly influences memory consolidation. Treatments that raise the level of IL-1beta in the brain, given after training, impair contextual fear conditioning. The melanocortin alpha-MSH exerts potent anti-inflammatory actions by physiologically antagonizing the effect of pro-inflammatory cytokines. Five subtypes of melanocortin receptors (MC1R-MC5R) have been identified, with MC3R and MC4R predominating in the central nervous system. The present experiments show that injection of IL-1beta (5 ng/0.25 microl) in dorsal hippocampus up to 15 min after training decreased freezing during the contextual fear test. The treatment with IL-1beta (5 ng/0.25 microl) 12h after conditioning cause amnesia when animals were tested 7 days post training. Thus, our results also demonstrated that IL-1beta can influence persistence of long-term memory. We determined that animals previously injected with IL-1beta can acquire a new contextual fear memory, demonstrating that the hippocampus was not damaged. Treatment with alpha-MSH (0.05 microg/0.25 microl) blocked the effect of IL-1beta on contextual fear memory. Administration of the MC4 receptor antagonist HS014 (0.5 microg/0.25 microl) reversed the effect of alpha-MSH. However, treatment with gamma-MSH (0.5 microg/0.25 microl), an MC3 agonist, did not affect IL-1beta-induced impairment of memory consolidation. These results suggest that alpha-MSH, through central MC4R can inhibit the effect of IL-1beta on memory consolidation.
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| 7. |
- Machado, Ivana, et al.
(författare)
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α-Melanocyte-stimulating hormone (α-MSH) reverses impairment of memory reconsolidation induced by interleukin-1 beta (IL-1 beta) hippocampal infusions
- 2010
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 31:11, s. 2141-2144
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-1 beta (IL-1β) significantly influences cognitive processes. Treatments which raise the level of IL-1β in the brain impair memory consolidation in contextual fear conditioning. However, the effect of IL-1β on memory reconsolidation has not yet been established. The melanocortin α-melanocyte-stimulating hormone (α-MSH) exerts potent anti-inflammatory actions by antagonizing the effect of proinflammatory cytokines. Five subtypes of melanocortin receptors (MC1R-MC5R) have been identified, of which MC3R and MC4R are predominant in the central nervous system. The present experiments show that the injection of IL-1β (5 ng/0.25 μl) in dorsal hippocampus up to 30 min after re-exposition to the context decreases freezing during the contextual fear test. Impairment of memory reconsolidation was reversed by treatment with α-MSH (0.05 μg/0.25 μl). Administration of the MC4 receptor antagonist HS014 (0.5 μg/0.25 μl) blocked the effect of α-MSH. These results suggest that IL-1β may influence memory reconsolidation and that activation of central MC4R could lead to improve cognitive performance.
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| 8. |
- Poretti, María Belén, et al.
(författare)
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Ghrelin effects expression of several genes associated with depression-like behavior
- 2015
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Ingår i: Progress in Neuro-psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 56, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- Ghrelin (Ghr) is an orexigenic peptide that is being investigated for its potential role in development of anxiety-like behavior and modulation of depressive-like symptoms induced by bilateral olfactory bulbectomy (OB) in rodents. Olfactory bulbectomy is an animal model useful to study of depression and Ghr could be an alternative therapeutic tool in depression therapy. We studied the effects of intracerebroventricular (i.c.v.) Ghr administration on the expression of hypothalamic genes related to depression and mood (delta opioid receptor (DOR), mu opioid receptor (MOR) and kappa opioid receptor (KOR), lutropin-choriogonadotropic hormone receptor (LHCGR), serotonin transporter (SERT), interleukin 1 beta (IL-1b), vasopressin (AVP) and corticotrophin releasing hormone (CRH)) in OB animals, as well as changes in plasma levels of AVP, CRH and adenocorticotropic hormone (ACTH). We found that acute Ghr 0.3nmol/μl administration increases gene expression of DOR, SERT and LHCGR in OB mice and decreased expression of IL-1b, suggesting that these genes could be involved in the antidepressant-like effects of Ghr. In addition, OB animals exhibit high AVP gene expression and elevated plasma concentrations of AVP and ACTH and acute Ghr 0.3nmol/μl administration reduces AVP gene expression and the concentration of these hormones, suggesting that peptide-effects on depressive-like behavior could be mediated at least in part via AVP. In conclusion, this study provides new evidence about genes, receptors and hormones involved in the antidepressant mechanism/s induced by Ghr in OB animals.
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| 9. |
- Rukh, Gull, et al.
(författare)
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Effect of worry, depression, and sensitivity to environmental stress owing to neurotic personality on risk of cardiovascular disease : A Mendelian randomization study
- 2023
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Ingår i: Journal of personality. - : John Wiley & Sons. - 0022-3506 .- 1467-6494. ; 91:3, s. 856-867
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThis study investigated the putative causal link between neuroticism (using three genetically distinct subclusters namely depressed affect, worry, and sensitivity to environmental stress and adversity [SESA]) and cardiovascular disease (CVD).MethodA two-sample bi-directional Mendelian randomization (MR) approach was used. Genetic instruments were extracted from publically available GWAS summary statistics.ResultsIn forward MR analyses with neuroticism subclusters as exposures, no causal associations between worry or SESA cluster and any of the CVD traits were observed (p > .05 for all). However, a higher risk of having heart failure (odds ratio (95% confidence interval):1.32(1.12 to 1.56); p = .0011) and myocardial infarction (1.47[1.18 to 1.83]; p = 6.3 × 10-4) associated with depressed affect cluster was observed. In reverse MR analyses with CVD traits as exposures, no significant associations were observed (p > .05 for all).ConclusionsIndividuals with high neuroticism who are more susceptible to depressive symptoms are at higher risk for developing heart failure and myocardial infarction and should be more carefully evaluated for CVD risk in clinical settings. These individuals can potentially benefit from interventions aimed at reducing depressive symptoms to decrease CVD risk. There is no evidence to suggest that being sensitive to environmental stressors or being more worried can increase the risk for CVD.
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| 10. |
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