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Gajewska A, Strzelecki D, Gawlik-Kotelnicka O. Ghrelin as a Biomarker of "Immunometabolic Depression" and Its Connection with Dysbiosis. Nutrients 2023; 15:3960. [PMID: 37764744 PMCID: PMC10537261 DOI: 10.3390/nu15183960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023] Open
Abstract
Ghrelin, a gastrointestinal peptide, is an endogenous ligand of growth hormone secretagogue receptor 1a (GHSR1a), which is mainly produced by X/A-like cells in the intestinal mucosa. Beyond its initial description as a growth hormone (GH) secretagogue stimulator of appetite, ghrelin has been revealed to have a wide range of physiological effects, for example, the modulation of inflammation; the improvement of cardiac performance; the modulation of stress, anxiety, taste sensation, and reward-seeking behavior; and the regulation of glucose metabolism and thermogenesis. Ghrelin secretion is altered in depressive disorders and metabolic syndrome, which frequently co-occur, but it is still unknown how these modifications relate to the physiopathology of these disorders. This review highlights the increasing amount of research establishing the close relationship between ghrelin, nutrition, microbiota, and disorders such as depression and metabolic syndrome, and it evaluates the ghrelinergic system as a potential target for the development of effective pharmacotherapies.
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Affiliation(s)
- Agata Gajewska
- Faculty of Medicine, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Dominik Strzelecki
- Department of Affective and Psychotic Disorders, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Oliwia Gawlik-Kotelnicka
- Department of Affective and Psychotic Disorders, Medical University of Lodz, 92-216 Lodz, Poland;
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2
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Reich N, Hölscher C. Beyond Appetite: Acylated Ghrelin As A Learning, Memory and Fear Behavior-modulating Hormone. Neurosci Biobehav Rev 2022; 143:104952. [DOI: 10.1016/j.neubiorev.2022.104952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 04/27/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022]
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Belardo C, Alessio N, Pagano M, De Dominicis E, Infantino R, Perrone M, Iannotta M, Galderisi U, Rinaldi B, Scuteri D, Bagetta G, Palazzo E, Maione S, Luongo L. PEA-OXA ameliorates allodynia, neuropsychiatric and adipose tissue remodeling induced by social isolation. Neuropharmacology 2022; 208:108978. [DOI: 10.1016/j.neuropharm.2022.108978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/10/2021] [Accepted: 01/30/2022] [Indexed: 12/28/2022]
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van Galen KA, Booij J, Schrantee A, Adriaanse SM, Unmehopa UA, Fliers E, Schwartz GJ, DiLeone RJ, Ter Horst KW, la Fleur SE, Serlie MJ. The response to prolonged fasting in hypothalamic serotonin transporter availability is blunted in obesity. Metabolism 2021; 123:154839. [PMID: 34331964 PMCID: PMC8994212 DOI: 10.1016/j.metabol.2021.154839] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/17/2021] [Accepted: 07/20/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND AND AIMS Serotonergic and dopaminergic systems in the brain are essential for homeostatic and reward-associated regulation of food intake and systemic energy metabolism. It is largely unknown how fasting influences these systems or if such effects are altered in humans with obesity. We therefore aimed to evaluate the effects of fasting on hypothalamic/thalamic serotonin transporter (SERT) and striatal dopamine transporter (DAT) availability in lean subjects and subjects with obesity. METHODS In this randomized controlled cross-over trial, we assessed the effects of 12 vs 24 h of fasting on SERT and DAT availability in the hypothalamus/thalamus and striatum, respectively, using SPECT imaging in 10 lean men and 10 men with obesity. RESULTS As compared with the 12-h fast, a 24-h fast increased hypothalamic SERT availability in lean men, but not in men with obesity. We observed high inter-individual variation in the effects of fasting on thalamic SERT and striatal DAT, with no differences between lean men and those with obesity. In all subjects, fasting-induced increases in circulating free fatty acid (FFA) concentrations were associated with an increase in hypothalamic SERT availability and a decrease in striatal DAT availability. Multiple regression analysis showed that changes in plasma insulin and FFAs together accounted for 44% of the observed variation in striatal DAT availability. CONCLUSION Lean men respond to prolonged fasting by increasing hypothalamic SERT availability, whereas this response is absent in men with obesity. Inter-individual differences in the adaptations of the cerebral serotonergic and dopaminergic systems to fasting may, in part, be explained by changes in peripheral metabolic signals of fasting, including FFAs and insulin.
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Affiliation(s)
- Katy A van Galen
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Anouk Schrantee
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Sofie M Adriaanse
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Unga A Unmehopa
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Gary J Schwartz
- Fleischer Institute for Diabetes and Metabolism, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ralph J DiLeone
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Kasper W Ter Horst
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands
| | - Susanne E la Fleur
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands; Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam University Medical Centers, University of Amsterdam, the Netherlands; Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC, Amsterdam, the Netherlands.
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Yao T, He J, Cui Z, Wang R, Bao K, Huang Y, Wang R, Liu T. Central 5-HTR2C in the Control of Metabolic Homeostasis. Front Endocrinol (Lausanne) 2021; 12:694204. [PMID: 34367066 PMCID: PMC8334728 DOI: 10.3389/fendo.2021.694204] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/06/2021] [Indexed: 11/29/2022] Open
Abstract
The 5-hydroxytryptamine 2C receptor (5-HTR2C) is a class G protein-coupled receptor (GPCR) enriched in the hypothalamus and the brain stem, where it has been shown to regulate energy homeostasis, including feeding and glucose metabolism. Accordingly, 5-HTR2C has been the target of several anti-obesity drugs, though the associated side effects greatly curbed their clinical applications. Dissecting the specific neural circuits of 5-HTR2C-expressing neurons and the detailed molecular pathways of 5-HTR2C signaling in metabolic regulation will help to develop better therapeutic strategies towards metabolic disorders. In this review, we introduced the regulatory role of 5-HTR2C in feeding behavior and glucose metabolism, with particular focus on the molecular pathways, neural network, and its interaction with other metabolic hormones, such as leptin, ghrelin, insulin, and estrogens. Moreover, the latest progress in the clinical research on 5-HTR2C agonists was also discussed.
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Affiliation(s)
- Ting Yao
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi’an Jiaotong University School of Medicine, Xi’an, China
- *Correspondence: Ting Yao, ; Ru Wang, ; Tiemin Liu,
| | - Jiehui He
- School of Life Sciences, Fudan University, Shanghai, China
| | - Zhicheng Cui
- School of Life Sciences, Fudan University, Shanghai, China
| | - Ruwen Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Kaixuan Bao
- Human Phenome Institute, Fudan University, Shanghai, China
| | - Yiru Huang
- School of Life Sciences, Fudan University, Shanghai, China
| | - Ru Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- *Correspondence: Ting Yao, ; Ru Wang, ; Tiemin Liu,
| | - Tiemin Liu
- School of Life Sciences, Fudan University, Shanghai, China
- Human Phenome Institute, Fudan University, Shanghai, China
- State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
- *Correspondence: Ting Yao, ; Ru Wang, ; Tiemin Liu,
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6
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Fritz EM, Singewald N, De Bundel D. The Good, the Bad and the Unknown Aspects of Ghrelin in Stress Coping and Stress-Related Psychiatric Disorders. Front Synaptic Neurosci 2020; 12:594484. [PMID: 33192444 PMCID: PMC7652849 DOI: 10.3389/fnsyn.2020.594484] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022] Open
Abstract
Ghrelin is a peptide hormone released by specialized X/A cells in the stomach and activated by acylation. Following its secretion, it binds to ghrelin receptors in the periphery to regulate energy balance, but it also acts on the central nervous system where it induces a potent orexigenic effect. Several types of stressors have been shown to stimulate ghrelin release in rodents, including nutritional stressors like food deprivation, but also physical and psychological stressors such as foot shocks, social defeat, forced immobilization or chronic unpredictable mild stress. The mechanism through which these stressors drive ghrelin release from the stomach lining remains unknown and, to date, the resulting consequences of ghrelin release for stress coping remain poorly understood. Indeed, ghrelin has been proposed to act as a stress hormone that reduces fear, anxiety- and depression-like behaviors in rodents but some studies suggest that ghrelin may - in contrast - promote such behaviors. In this review, we aim to provide a comprehensive overview of the literature on the role of the ghrelin system in stress coping. We discuss whether ghrelin release is more than a byproduct of disrupted energy homeostasis following stress exposure. Furthermore, we explore the notion that ghrelin receptor signaling in the brain may have effects independent of circulating ghrelin and in what way this might influence stress coping in rodents. Finally, we examine how the ghrelin system could be utilized as a therapeutic avenue in stress-related psychiatric disorders (with a focus on anxiety- and trauma-related disorders), for example to develop novel biomarkers for a better diagnosis or new interventions to tackle relapse or treatment resistance in patients.
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Affiliation(s)
- Eva Maria Fritz
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Dimitri De Bundel
- Department of Pharmaceutical Sciences, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
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Stone LA, Harmatz ES, Goosens KA. Ghrelin as a Stress Hormone: Implications for Psychiatric Illness. Biol Psychiatry 2020; 88:531-540. [PMID: 32912426 DOI: 10.1016/j.biopsych.2020.05.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 12/28/2022]
Abstract
The stress response is an adaptive means of maintaining physiological homeostasis in the face of changing environmental conditions. However, protracted recruitment of stress systems can precipitate wear and tear on the body and may lead to many forms of disease. The mechanisms underlying the connection between chronic stress and disease are not fully understood and are likely multifactorial. In this review, we evaluate the possibility that the hormone ghrelin may contribute to the pathophysiology that follows chronic stress. Since ghrelin was discovered as a pro-hunger hormone, many additional roles for it have been identified, including in learning, memory, reward, and stress. We describe the beneficial effects that ghrelin exerts in healthy mammals and discuss that prolonged exposure to ghrelin has been linked to maladaptive responses and behaviors in the realm of psychiatric disease. In addition, we consider whether chronic stress-associated altered ghrelin signaling may enhance susceptibility to posttraumatic stress disorder and comorbid conditions such as major depressive disorder and alcohol use disorder. Finally, we explore the possibility that ghrelin-based therapeutics could eventually form the basis of a treatment strategy for illnesses that are linked to chronic stress and potentially also ghrelin dysregulation, and we identify critical avenues for future research in this regard.
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Affiliation(s)
| | | | - Ki A Goosens
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.
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Larsen AT, Sonne N, Andreassen KV, Karsdal MA, Henriksen K. Dose Frequency Optimization of the Dual Amylin and Calcitonin Receptor Agonist KBP-088: Long-Lasting Improvement in Food Preference and Body Weight Loss. J Pharmacol Exp Ther 2020; 373:269-278. [DOI: 10.1124/jpet.119.263400] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
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9
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Ozmen S, Şeker A, Demirci E. Ghrelin and leptin levels in children with anxiety disorders. J Pediatr Endocrinol Metab 2019; 32:1043-1047. [PMID: 31472067 DOI: 10.1515/jpem-2019-0229] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/28/2019] [Indexed: 11/15/2022]
Abstract
Background Anxiety disorders are common psychiatric disorders in childhood and an important health problem that is associated with the risk of serious mental, educational and economical problems. Researchers have mentioned many different mechanisms in the etiopathology of anxiety disorders. This study aimed to investigate ghrelin and leptin levels in children with anxiety disorders and thus to contribute to the clarification of anxiety in children. Methods Forty-three children aged 6-12 years with a diagnosis of the Anxiety Disorder according to DSM 5 and 21 healthy children age- and gender-matched to the study group were included. All the subjects were assessed with Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (K-SADS-PL) and State-Trait Anxiety Inventory for Children (STAI-C) scale. Blood samples were obtained in the morning and serum ghrelin and leptin levels were measured with enzyme-linked immunosorbent assay (ELISA) kits. Results In the anxiety group the ghrelin levels were higher than the control group (p = 0.037) but there was no significant difference between the leptin levels (p = 0.430). Also, when the girls in the anxiety group and the girls in the control group were compared, ghrelin levels were higher in the anxiety group (p < 0.01). Conclusions These findings suggest that ghrelin may play a significant role in the etiologic mechanisms of anxiety disorders. However, more detailed studies are needed to explain the linkage between anxiety disorders and neuropeptides.
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Affiliation(s)
- Sevgi Ozmen
- Erciyes University Hospital, Child and Adolescent Psychiatry Department, Melikgazi, Kayseri, Turkey
| | - Asilay Şeker
- Erciyes University Hospital, Child and Adolescent Psychiatry Department, Melikgazi, Kayseri, Turkey
| | - Esra Demirci
- Erciyes University Hospital, Child and Adolescent Psychiatry Department, Melikgazi, Kayseri, Turkey
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Methyl Donor Deficiency during Gestation and Lactation in the Rat Affects the Expression of Neuropeptides and Related Receptors in the Hypothalamus. Int J Mol Sci 2019; 20:ijms20205097. [PMID: 31615150 PMCID: PMC6829491 DOI: 10.3390/ijms20205097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/04/2019] [Accepted: 10/12/2019] [Indexed: 02/07/2023] Open
Abstract
The micronutrients vitamins B9 and B12 act as methyl donors in the one-carbon metabolism involved in transmethylation reactions which critically influence epigenetic mechanisms and gene expression. Both vitamins are essential for proper development, and their deficiency during pregnancy has been associated with a wide range of disorders, including persisting growth retardation. Energy homeostasis and feeding are centrally regulated by the hypothalamus which integrates peripheral signals and acts through several orexigenic and anorexigenic mediators. We studied this regulating system in a rat model of methyl donor deficiency during gestation and lactation. At weaning, a predominance of the anorexigenic pathway was observed in deficient pups, with increased plasma peptide YY and increased hypothalamic pro-opiomelanocortin (POMC) mRNA, in line with abnormal leptin, ghrelin, and insulin secretion and/or signaling during critical periods of fetal and/or postnatal development of the hypothalamus. These results suggest that early methyl donor deficiency can affect the development and function of energy balance circuits, resulting in growth and weight deficits. Maternal administration of folic acid (3 mg/kg/day) during the perinatal period tended to rectify peripheral metabolic signaling and central neuropeptide and receptor expression, leading to reduced growth retardation.
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Association between waist-to-height ratio and anxiety in middle-aged women: a secondary analysis of a cross-sectional multicenter Latin American study. Menopause 2019; 25:904-911. [PMID: 29509599 DOI: 10.1097/gme.0000000000001089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The aim of the study was to evaluate the association between waist-to-height ratio (WHtR) and anxiety in middle-aged women. METHODS We carried out a secondary analysis of data from a multicenter study of women between 40 and 59 years old from 11 Latin America countries. Anxiety was assessed using the Goldberg Anxiety and Depression Scale. WHtR was calculated according to World Health Organization standards and categorized in tertiles: upper, middle, and lower using 0.45 and 0.6 as cutoff values. Prevalence ratios (PRs) and 95% CIs were calculated by generalized linear models of Poisson family with robust standard errors, both crude and adjusted models based on statistical and epidemiological criteria. RESULTS Data of a total of 5,580 women were analyzed. Mean age was 49.7 ± 5.5 years, and 57.9% were postmenopausal. The 61.3% of women had anxiety and mean WHtR was 0.54 ± 0.1. In the crude model, compared with women in lower tertile, those in the middle (PR: 1.07; 95% CI, 1.01-1.13) and upper (PR: 1.23 95% CI, 1.07-1.29) WHtR tertile were significantly more likely to have anxiety. In the adjusted models, only women in upper tertile were, however, more likely of displaying anxiety than those in lower tertile (PR: 1.13; 95% CI, 1.08-1.18). CONCLUSIONS In this series, WHtR was associated with anxiety in middle-aged women. It is advisable to further study this anthropometric measure in order for it to be incorporated in the routine clinical practice and evaluation of middle-aged women.
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Lee SB, Lee KW, Wang T, Lee JS, Jung US, Nejad JG, Oh YK, Baek YC, Kim KH, Lee HG. Intravenous administration of L-tryptophan stimulates gastrointestinal hormones and melatonin secretions: study on beef cattle. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2019; 61:239-244. [PMID: 31452911 PMCID: PMC6686141 DOI: 10.5187/jast.2019.61.4.239] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 01/26/2023]
Abstract
This study aimed to determine the effective dose of intravenous administration of L-tryptophan (L-T) on gastrointestinal hormones (GIH) secretions and melatonin using Hanwoo cattle. Three steers (362 ± 23 kg) fitted with indwelling jugular vein catheters were assigned in a 3 × 3 Latin square design. Treatments were intravenous administration of saline (control), 28.9 mg L-T/kg body weight (BW; low) and 57.8 mg L-T/kg BW (high) L-T for 1 day with 7 days of adaptation. Samples were collected after adaptation period at -60, 0, 30, 60, 90, 120, 150, 180, 240, and 300 min of sampling day. The levels of serum cholecystokinin (CCK) and secretin were higher (p < 0.05) in the high L-T group than those in the other groups. Serum Melatonin (MEL) levels were increased upon L-T administration (p < 0.05) in the high L-T group. Taken together, the effective dose of L-T administration was defined at 57.8 mg L-T/kg BW in order to stimulate increase of GIH and MEL.
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Affiliation(s)
- Sang-Bum Lee
- Department of Animal Science and Technology, College of Animal
Bioscience and Technology, Konkuk University, Seoul 05029,
Korea
| | | | - Tao Wang
- Department of Animal Nutrition and Feed Science, College of Animal
Science and Technology, Jilin Agricultural University, Jilin 130118,
China
| | - Jae-Sung Lee
- Department of Animal Science and Technology, College of Animal
Bioscience and Technology, Konkuk University, Seoul 05029,
Korea
- An Educational Program for Specialists in Global Animal Science,
Brain Korea 21 Plus Project, Konkuk University, Seoul 05029,
Korea
| | - U-Suk Jung
- Department of Animal Science and Technology, College of Animal
Bioscience and Technology, Konkuk University, Seoul 05029,
Korea
| | - Jalil Ghassemi Nejad
- Department of Animal Science and Technology, College of Animal
Bioscience and Technology, Konkuk University, Seoul 05029,
Korea
- An Educational Program for Specialists in Global Animal Science,
Brain Korea 21 Plus Project, Konkuk University, Seoul 05029,
Korea
| | - Young-Kyoon Oh
- Department of Nutrition and Physiology, National Institute of
Animal Science, RDA, JeonJu 55365, Korea
| | - Youl-Chang Baek
- Department of Nutrition and Physiology, National Institute of
Animal Science, RDA, JeonJu 55365, Korea
| | - Kyoung Hoon Kim
- Graduate School of International Agricultural Technology,
Pyeongchang Campus, Seoul National University, Pyeongchang 25354,
Korea
| | - Hong-Gu Lee
- Department of Animal Science and Technology, College of Animal
Bioscience and Technology, Konkuk University, Seoul 05029,
Korea
- An Educational Program for Specialists in Global Animal Science,
Brain Korea 21 Plus Project, Konkuk University, Seoul 05029,
Korea
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Ogawa S, Liu X, Shepherd BS, Parhar IS. Ghrelin stimulates growth hormone release from the pituitary via hypothalamic growth hormone-releasing hormone neurons in the cichlid, Oreochromis niloticus. Cell Tissue Res 2018; 374:349-365. [PMID: 29934855 DOI: 10.1007/s00441-018-2870-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 06/04/2018] [Indexed: 12/25/2022]
Abstract
Ghrelin, a gut-brain peptide hormone, is implicated in a multiplicity of biological functions, including energy homeostasis and reproduction. Neuronal systems that are involved in energy homeostasis as well as reproduction traverse the hypothalamus; however, the mechanism by which they control energy homeostasis is not fully understood. The present study analyzes the anatomical relationship of neurons expressing gonadotropin-releasing hormone (GnRH), neuropeptide Y (NPY) and growth hormone-releasing hormone (GHRH) in a cichlid, tilapia (Oreochromis niloticus). Additionally, we examine in vivo effects of ghrelin on these hypothalamic neurons and plasma growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels. Double-immunofluorescence showed neuronal fiber associations between GnRH, NPY and GHRH in the brain and pituitary. Intracerebroventricular injection of ghrelin had no effect on numbers, soma size, or optical density of GnRH and NPY neurons, whereas the number of GHRH neurons was significantly decreased in the animals injected with ghrelin when compared to controls, which may indicate administered ghrelin promoted GHRH release. Plasma GH and pituitary GH mRNA levels were significantly increased in the animals injected with ghrelin. These results suggest that central administration of ghrelin primarily act on hypothalamic GHRH neurons to stimulate GH release from the pituitary in the tilapia.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500, Bandar Sunway, Selangor, Malaysia
| | - Xiaochun Liu
- School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Brian S Shepherd
- USDA/ARS/School of Freshwater Sciences, University of Wisconsin, Milwaukee, WI, 53204, USA
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500, Bandar Sunway, Selangor, Malaysia.
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Kirsz K, Szczesna M, Molik E, Zieba DA. Effects of ghrelin on nocturnal melatonin secretion in sheep: An in vitro and in vivo approach1. J Anim Sci 2017. [DOI: 10.2527/jas.2017.1737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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15
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Atescelik M, Yilmaz M, Korkmaz S, Goktekin MC, Gurger M, Ilhan N. The Relationship between Ghrelin and Copeptin Levels, and Anxiety and Depression Levels in Suicide Attempts. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2017; 15:256-260. [PMID: 28783935 PMCID: PMC5565089 DOI: 10.9758/cpn.2017.15.3.256] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/13/2016] [Accepted: 10/05/2016] [Indexed: 11/18/2022]
Abstract
Objective It was aimed to detect acylated ghrelin (AG), unacylated ghrelin (UG) and copeptin levels in patients with suicide attempts and to determine if these biomarkers are risk factors for suicide attempts. Methods Serum copeptin, AG and GU levels were screened in 128 patients who were admitted to emergency department with suicide attempts and 59 healthy controls. Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were applied simultaneously, and the data were compared statistically. Results AG, UG and copeptin levels were higher in the patient group compared with the healthy control group. BAI scores of patients were found to be positively correlated with BDI scores. While there was a significant difference (p=0.0064) between psychiatric and non-psychiatric patients with suicide attempts in terms of BAI scores, there were no differences in BDI scores and levels of biomarkers. We found significantly increased BDI and BAI scores and increased levels of AG, UG and copeptin in psychiatric and non-psychiatric patients compared with healthy individuals. The specificities yielded by receiver operating characteristic curve analysis in patients with suicide attempts were as follows: 91.53% for AG, 72.88% for UG and 94.92% for copeptin. Conclusion Serum levels of AG, UG and copeptin increase with increasing anxiety and depression in patients with suicide attempts. Increased levels of AG, UG and copeptin could be considered a risk factor for suicide attempts.
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Affiliation(s)
- Metin Atescelik
- Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey
| | - Mustafa Yilmaz
- Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey
| | - Sevda Korkmaz
- Department of Psychiatry, Firat University School of Medicine, Elazig, Turkey
| | - Mehmet Cagri Goktekin
- Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey
| | - Mehtap Gurger
- Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey
| | - Nevin Ilhan
- Department of Biochemistry, Firat University School of Medicine, Elazig, Turkey
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Longitudinal changes of associations between the preproghrelin Leu72Met polymorphism with depression in Chinese Han adolescents after the Wenchuan earthquake. Psychiatr Genet 2017; 27:161-168. [PMID: 28570394 DOI: 10.1097/ypg.0000000000000180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
AIM The present study aimed to investigate longitudinal associations of preproghrelin Leu72Met with depression in Chinese Han adolescents after the Wenchuan earthquake in 2008. MATERIALS AND METHODS A total of 709 volunteers were enrolled from a high school near the epicenter of the earthquake and 662, 643, and 510 students were finally included at 6, 12, and 18 months, respectively, after the earthquake. Depressive symptoms were assessed using the Beck Depression Inventory (BDI). The genotypes were identified by PCR-restriction fragment length polymorphism analyses and verified by DNA sequencing. RESULTS Females had a higher prevalence of depression than males at 6 months after the earthquake in 72Leu/Leu homozygotes (χ-test, P=0.007), but not in 72Met allele carriers. 72Met allele carriers had lower prevalence (χ-test, P=0.025) and BDI scores (Kruskal-Wallis test, P=0.034) than 72Leu/Leu homozygotes only among males at 18 months, but not at 6 or 12 months. The prevalence was consecutively decreased in male 72Met allele carriers (χ-test, P=0.010), but not in male 72Leu/Leu homozygotes, female 72Met allele carriers, or female 72Leu/Leu homozygotes during follow-up. Potential factors of depression prevalence and predictors of BDI scores were different between 72Leu/Leu homozygotes and 72Met allele carriers at different time points during follow-up. CONCLUSION These results suggest that the 72Met allele of the preproghrelin Leu72Met polymorphism may be associated with rehabilitation of depression in male Chinese Han adolescents after the natural disaster.
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17
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Locatelli M, Ferrante C, Carradori S, Secci D, Leporini L, Chiavaroli A, Leone S, Recinella L, Orlando G, Martinotti S, Brunetti L, Vacca M, Menghini L. Optimization of Aqueous Extraction and Biological Activity of Harpagophytum procumbens Root on Ex Vivo Rat Colon Inflammatory Model. Phytother Res 2017; 31:937-944. [PMID: 28447368 DOI: 10.1002/ptr.5821] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 12/22/2022]
Abstract
Harpagophytum procumbens has a long story of use for the treatment of inflammatory diseases. Considering both the antiinflammatory effects of H. procumbens in multiple tissues and the stability of harpagoside in artificial intestinal fluid, the aim of the present study was to explore the possible protective role of a microwave-assisted aqueous Harpagophytum extract (1-1000 μg/mL) on mouse myoblast C2C12 and human colorectal adenocarcinoma HCT116 cell lines, and isolated rat colon specimens challenged with lipopolysaccharide (LPS), a validated ex vivo model of acute ulcerative colitis. In this context, we evaluated the effects on C2C12 and HCT116 viability, and on LPS-induced production of serotonin (5-HT), tumor necrosis factor (TNF)-α, prostaglandin (PG)E2 and 8-iso-prostaglandin (8-iso-PG)F2α . Harpagophytum extract was well tolerated by C2C12 cells, while reduced HCT116 colon cancer cell viability. On the other hand, Harpagophytum extract reduced H2 O2 -induced (1 mM) reactive oxygen species (ROS) production, in both cell lines, and inhibited LPS-induced colon production of PGE2 , 8-iso-PGF2α , 5-HT and TNFα. Concluding, we demonstrated the efficacy of a microwave-assisted Harpagophytum aqueous extract in modulating the inflammatory, oxidative stress and immune response in an experimental model of inflammatory bowel diseases (IBD), thus suggesting a rational use of Harpagophytum in the management and prevention of ulcerative colitis in humans. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Marcello Locatelli
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Claudio Ferrante
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Simone Carradori
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Daniela Secci
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy
| | - Lidia Leporini
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Annalisa Chiavaroli
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Sheila Leone
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Lucia Recinella
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Giustino Orlando
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Sara Martinotti
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Luigi Brunetti
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Michele Vacca
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
| | - Luigi Menghini
- Department of Pharmacy, G. D'Annunzio University Chieti-Pescara, Via dei Vestini 31, 66100, Chieti, Italy
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18
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Clarifying the Ghrelin System's Ability to Regulate Feeding Behaviours Despite Enigmatic Spatial Separation of the GHSR and Its Endogenous Ligand. Int J Mol Sci 2017; 18:ijms18040859. [PMID: 28422060 PMCID: PMC5412441 DOI: 10.3390/ijms18040859] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/04/2017] [Accepted: 04/11/2017] [Indexed: 12/23/2022] Open
Abstract
Ghrelin is a hormone predominantly produced in and secreted from the stomach. Ghrelin is involved in many physiological processes including feeding, the stress response, and in modulating learning, memory and motivational processes. Ghrelin does this by binding to its receptor, the growth hormone secretagogue receptor (GHSR), a receptor found in relatively high concentrations in hypothalamic and mesolimbic brain regions. While the feeding and metabolic effects of ghrelin can be explained by the effects of this hormone on regions of the brain that have a more permeable blood brain barrier (BBB), ghrelin produced within the periphery demonstrates a limited ability to reach extrahypothalamic regions where GHSRs are expressed. Therefore, one of the most pressing unanswered questions plaguing ghrelin research is how GHSRs, distributed in brain regions protected by the BBB, are activated despite ghrelin’s predominant peripheral production and poor ability to transverse the BBB. This manuscript will describe how peripheral ghrelin activates central GHSRs to encourage feeding, and how central ghrelin synthesis and ghrelin independent activation of GHSRs may also contribute to the modulation of feeding behaviours.
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19
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Gydesen S, Hjuler ST, Freving Z, Andreassen KV, Sonne N, Hellgren LI, Karsdal MA, Henriksen K. A novel dual amylin and calcitonin receptor agonist, KBP-089, induces weight loss through a reduction in fat, but not lean mass, while improving food preference. Br J Pharmacol 2017; 174:591-602. [PMID: 28109166 DOI: 10.1111/bph.13723] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Obesity and associated co-morbidities, such as type 2 diabetes and non-alcoholic fatty liver disease, are major health challenges. Hence, there is an important need to develop weight loss therapies with the ability to reduce the co-morbidities. EXPERIMENTAL APPROACH The effect of the dual amylin and calcitonin receptor agonist (DACRA), KBP-089, on body weight, glucose homeostasis and fatty acid accumulation in liver and muscle tissue and on food preference was investigated. Furthermore, we elucidated weight-independent effects of KBP-089 using a weight-matched group. KEY RESULTS Rats fed a high-fat diet were treated, s.c., with KBP-089 0.625, 1.25, 2.5 μg·kg-1 or vehicle. KB-089 induced in a dose-dependent and sustained weight loss (~17% by 2.5 μg·kg-1 ). Moreover, KBP-089 reduced fat depot size and reduced lipid accumulation in muscle and liver. In Zucker Diabetic Fatty rats, KBP-089 improved glucose homeostasis through improved insulin action. To obtain a weight-matched group, significantly less food was offered (9% less than in the KBP-089 group). Weight matching led to improved glucose homeostasis by reducing plasma insulin; however, these effect were inferior compared to those of KBP-089. In the food preference test, rats fed a normal diet obtained 74% of their calories from chocolate. KBP-089 reduced total caloric intake and induced a relative increase in chow consumption while drastically reducing chocolate consumption compared with vehicle. CONCLUSIONS AND IMPLICATIONS The novel DACRA, KBP-089, induces a sustained weight loss, leading to improved metabolic parameters including food preference, and these are beyond those observed simply by diet-induced weight loss.
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Affiliation(s)
- Sofie Gydesen
- Nordic Bioscience, Herlev, Denmark.,Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | | | | | | | | | - Lars I Hellgren
- Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
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20
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Churm R, Davies JS, Stephens JW, Prior SL. Ghrelin function in human obesity and type 2 diabetes: a concise review. Obes Rev 2017; 18:140-148. [PMID: 27899023 DOI: 10.1111/obr.12474] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 12/12/2022]
Abstract
The 28 amino acid hormone, ghrelin, has been found to have various effects on metabolism. This review will focus on the pathways integrated into ghrelin's effect within the hypothalamus, pancreas and adipocytes. The identification of molecules and pathways that regulate ghrelin-mediated lipid retention could establish new mechanisms underlying cellular energy homeostasis. The impact of acyl-ghrelin on glucose metabolism and lipid homeostasis may allow for novel preventative or early intervention therapeutic strategies to treat obesity related type 2 diabetes and associated metabolic dysfunction.
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Affiliation(s)
- R Churm
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J S Davies
- Molecular Neurobiology Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J W Stephens
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - S L Prior
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
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21
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Al Massadi O, López M, Tschöp M, Diéguez C, Nogueiras R. Current Understanding of the Hypothalamic Ghrelin Pathways Inducing Appetite and Adiposity. Trends Neurosci 2017; 40:167-180. [PMID: 28108113 DOI: 10.1016/j.tins.2016.12.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 12/21/2022]
Abstract
Ghrelin is a multifaceted regulator of metabolism. Ghrelin regulates energy balance in the short term via induction of appetite and in the long term via increased body weight and adiposity. Recently, several central pathways modulating the metabolic actions of ghrelin were unmasked, and it was shown to act through different hypothalamic nuclei to induce feeding. Ghrelin also modulates glucose homeostasis, but the central mechanisms responsible for this action have not been studied in detail. Although ghrelin also acts through extrahypothalamic areas to promote feeding, this review specifically dissects hypothalamic control of ghrelin's orexigenic and adipogenic actions and presents current understanding of the intracellular ghrelin orexigenic pathways, including their dependence on other relevant systems implicated in energy balance.
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Affiliation(s)
- Omar Al Massadi
- Department of Physiology, School of Medicine-CiMUS, Instituto de Investigación Sanitaria (IDIS), University of Santiago de Compostela, Av de Barcelona s/n Santiago de Compostela (A Coruña), 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain.
| | - Miguel López
- Department of Physiology, School of Medicine-CiMUS, Instituto de Investigación Sanitaria (IDIS), University of Santiago de Compostela, Av de Barcelona s/n Santiago de Compostela (A Coruña), 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
| | - Matthias Tschöp
- Helmholtz Diabetes Center, Helmholtz Zentrum München and German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Carlos Diéguez
- Department of Physiology, School of Medicine-CiMUS, Instituto de Investigación Sanitaria (IDIS), University of Santiago de Compostela, Av de Barcelona s/n Santiago de Compostela (A Coruña), 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
| | - Ruben Nogueiras
- Department of Physiology, School of Medicine-CiMUS, Instituto de Investigación Sanitaria (IDIS), University of Santiago de Compostela, Av de Barcelona s/n Santiago de Compostela (A Coruña), 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain.
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22
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Brunetti L, Di Nisio C, Orlando G, Ferrante C, Vacca M. The Regulation of Feeding: A Cross Talk between Peripheral and Central Signalling. Int J Immunopathol Pharmacol 2016; 18:201-12. [PMID: 15888244 DOI: 10.1177/039463200501800203] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Feeding and energy expenditures are modulated by the interplay of hormones and neurotransmitters in the central nervous system (CNS), where the hypothalamus plays a pivotal role in the transduction of peripheral afferents into satiety and feeding signals. Aminergic neurotransmitters such as dopamine (DA), norepinephrine (NE) and serotonin (5-hydroxytryptamine, 5-HT) are historically considered to play a key role, but a number of peptides are involved in finely tuning feeding regulation. This review summarizes the current understanding of the CNS mechanisms of orexigenic peptides, such as neuropeptide Y, orexins, and ghrelin, as well as anorectic peptides, such as leptin, neurotensin (NT), cocaine- and amphetamine regulated transcript (CART) peptide, thyrotropin-releasing hormone (TRH), corticotropin-releasing hormone (CRH), urocortin, amylin.
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Affiliation(s)
- L Brunetti
- Department of Drug Sciences, G. D'Annunzio University, Chieti, Italy
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23
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Dwarkasing JT, Marks DL, Witkamp RF, van Norren K. Hypothalamic inflammation and food intake regulation during chronic illness. Peptides 2016; 77:60-6. [PMID: 26158772 DOI: 10.1016/j.peptides.2015.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/14/2015] [Accepted: 06/22/2015] [Indexed: 02/08/2023]
Abstract
Anorexia is a common symptom in chronic illness. It contributes to malnutrition and strongly affects survival and quality of life. A common denominator of many chronic diseases is an elevated inflammatory status, which is considered to play a pivotal role in the failure of food-intake regulating systems in the hypothalamus. In this review, we summarize findings on the role of hypothalamic inflammation on food intake regulation involving hypothalamic neuropeptide Y (NPY) and pro-opiomelanocortin (POMC). Furthermore, we outline the role of serotonin in the inability of these peptide based food-intake regulating systems to respond and adapt to changes in energy metabolism during chronic disease.
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Affiliation(s)
- J T Dwarkasing
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
| | - D L Marks
- Department of Pediatric Endocrinology, Oregon Health & Sciences University, Portland, OR 97201, USA
| | - R F Witkamp
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - K van Norren
- Nutrition and Pharmacology Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; Nutricia Research, Utrecht, The Netherlands
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24
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Interacting Neural Processes of Feeding, Hyperactivity, Stress, Reward, and the Utility of the Activity-Based Anorexia Model of Anorexia Nervosa. Harv Rev Psychiatry 2016; 24:416-436. [PMID: 27824637 PMCID: PMC5485261 DOI: 10.1097/hrp.0000000000000111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Anorexia nervosa (AN) is a psychiatric illness with minimal effective treatments and a very high rate of mortality. Understanding the neurobiological underpinnings of the disease is imperative for improving outcomes and can be aided by the study of animal models. The activity-based anorexia rodent model (ABA) is the current best parallel for the study of AN. This review describes the basic neurobiology of feeding and hyperactivity seen in both ABA and AN, and compiles the research on the role that stress-response and reward pathways play in modulating the homeostatic drive to eat and to expend energy, which become dysfunctional in ABA and AN.
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25
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Stemer B, Melmer A, Fuchs D, Ebenbichler C, Kemmler G, Deisenhammer EA. Bright versus dim ambient light affects subjective well-being but not serotonin-related biological factors. Psychiatry Res 2015; 229:1011-6. [PMID: 26260570 DOI: 10.1016/j.psychres.2015.05.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 03/20/2015] [Accepted: 05/26/2015] [Indexed: 01/03/2023]
Abstract
Light falling on the retina is converted into an electrical signal which stimulates serotonin synthesis. Previous studies described an increase of plasma and CNS serotonin levels after bright light exposure. Ghrelin and leptin are peptide hormones which are involved in the regulation of hunger/satiety and are related to serotonin. Neopterin and kynurenine are immunological markers which are also linked to serotonin biosynthesis. In this study, 29 healthy male volunteers were exposed to bright (5000lx) and dim (50lx) light conditions for 120min in a cross-over manner. Subjective well-being and hunger as well as various serotonin associated plasma factors were assessed before and after light exposure. Subjective well-being showed a small increase under bright light and a small decrease under dim light, resulting in a significant interaction between light condition and time. Ghrelin concentrations increased significantly under both light conditions, but there was no interaction between light and time. Correspondingly, leptin decreased significantly under both light conditions. Hunger increased significantly with no light-time interaction. We also found a significant decrease of neopterin, tryptophan and tyrosine levels, but no interaction between light and time. In conclusion, ambient light was affecting subjective well-being rather than serotonin associated biological factors.
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Affiliation(s)
- Bettina Stemer
- Department of General and Social Psychiatry, Center of Psychiatry and Psychotherapy, Austria
| | | | - Dietmar Fuchs
- Division of Biological Chemistry, Biocenter, Medical University Innsbruck, Austria
| | | | - Georg Kemmler
- Department of General and Social Psychiatry, Center of Psychiatry and Psychotherapy, Austria
| | - Eberhard A Deisenhammer
- Department of General and Social Psychiatry, Center of Psychiatry and Psychotherapy, Austria.
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26
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Schellekens H, De Francesco PN, Kandil D, Theeuwes WF, McCarthy T, van Oeffelen WEPA, Perelló M, Giblin L, Dinan TG, Cryan JF. Ghrelin's Orexigenic Effect Is Modulated via a Serotonin 2C Receptor Interaction. ACS Chem Neurosci 2015; 6:1186-97. [PMID: 25727097 DOI: 10.1021/cn500318q] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Understanding the intricate pathways that modulate appetite and subsequent food intake is of particular importance considering the rise in the incidence of obesity across the globe. The serotonergic system, specifically the 5-HT2C receptor, has been shown to be of critical importance in the regulation of appetite and satiety. The GHS-R1a receptor is another key receptor that is well-known for its role in the homeostatic control of food intake and energy balance. We recently showed compelling evidence for an interaction between the GHS-R1a receptor and the 5-HT2C receptor in an in vitro cell line system heterologously expressing both receptors. Here, we investigated this interaction further. First, we show that the GHS-R1a/5-HT2C dimer-induced attenuation of calcium signaling is not due to coupling to GαS, as no increase in cAMP signaling is observed. Next, flow cytometry fluorescence resonance energy transfer (fcFRET) is used to further demonstrate the direct interaction between the GHS-R1a receptor and 5-HT2C receptor. In addition, we demonstrate colocalized expression of the 5-HT2C and GHS-R1a receptor in cultured primary hypothalamic and hippocampal rat neurons, supporting the biological relevance of a physiological interaction. Furthermore, we demonstrate that when 5-HT2C receptor signaling is blocked ghrelin's orexigenic effect is potentiated in vivo. In contrast, the specific 5-HT2C receptor agonist lorcaserin, recently approved for the treatment of obesity, attenuates ghrelin-induced food intake. This underscores the biological significance of our in vitro findings of 5-HT2C receptor-mediated attenuation of GHS-R1a receptor activity. Together, this study demonstrates, for the first time, that the GHS-R1a/5-HT2C receptor interaction translates into a biologically significant modulation of ghrelin's orexigenic effect. This data highlights the potential development of a combined GHS-R1a and 5-HT2C receptor treatment strategy in weight management.
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Affiliation(s)
| | - Pablo N. De Francesco
- Laboratory
of Neurophysiology, Multidisciplinary Institute of Cell Biology, National Scientific and Technical Research Council, La Plata, Argentina
| | | | | | | | | | - Mario Perelló
- Laboratory
of Neurophysiology, Multidisciplinary Institute of Cell Biology, National Scientific and Technical Research Council, La Plata, Argentina
| | - Linda Giblin
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland
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Abstract
The anorexia of aging is common, leading to adverse health consequences. As populations age, the impacts from anorexia in the older population are set to increase. Only greater awareness will allow for prevention or early intervention. This article discusses the physiologic anorexia of aging, highlights contributing factors, and proposes management strategies, including screening, especially in primary care. Many neuroendocrine factors have been implicated in the pathophysiology; it is clear that further human research is necessary if there is to be a pharmacologic breakthrough. There are currently no approved pharmacologic treatment strategies to prevent or treat the anorexia of aging.
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Affiliation(s)
- Renuka Visvanathan
- Aged & Extended Care Services, Level 8B, The Queen Elizabeth Hospital, Woodville Road, Woodville South, Adelaide, SA 5011, Australia.
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28
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Growth Hormone Secretagogue Receptor Dimers: A New Pharmacological Target. eNeuro 2015; 2:eN-REV-0053-14. [PMID: 26464979 PMCID: PMC4596092 DOI: 10.1523/eneuro.0053-14.2015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 03/25/2015] [Accepted: 04/07/2015] [Indexed: 01/04/2023] Open
Abstract
The growth hormone secretagogue receptor (GHSR1a), the target of the ghrelin peptide, is widely distributed throughout the brain, and, while studies have often reported very low or absent levels of central ghrelin, it is now known that GHSR1a, even in the absence of a natural ligand, has physiological roles. Not only do these roles originate from the receptor's constitutive activity, but recent data indicate that GHSR1a dimerizes with a wide array of other receptors. These include the dopamine 1 receptor (D1R), the dopamine 2 receptor (D2R), the melanocortin-3 receptor (MC3R), the serotonin 2C receptor (5-HT2C), and possibly the cannabinoid type 1 receptor (CB1). Within these dimers, signaling of the protomers involved are modified through facilitation, inhibition, and even modification of signaling pathways resulting in physiological consequences not seen in the absence of these dimers. While in some cases the ghrelin peptide is not required for these modifications to occur, in others, the presence is necessary for these changes to take effect. These heterodimers demonstrate the broad array of roles and complexity of the ghrelin system. By better understanding how these dimers work, it is hoped that improved treatments for a variety of disorders, including Parkinson's disease, schizophrenia, addiction, obesity, diabetes, and more, can be devised. In this review, we examine the current state of knowledge surrounding GHSR heterodimers, and how we can apply this knowledge to various pharmacological treatments.
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29
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Ghrelin effects expression of several genes associated with depression-like behavior. Prog Neuropsychopharmacol Biol Psychiatry 2015; 56:227-34. [PMID: 25286107 DOI: 10.1016/j.pnpbp.2014.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/23/2014] [Accepted: 09/23/2014] [Indexed: 02/03/2023]
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 0.3 nmol/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 0.3 nmol/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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30
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Akter S, Pham NM, Nanri A, Kurotani K, Kuwahara K, Jacka FN, Yasuda K, Sato M, Mizoue T. Association of serum leptin and ghrelin with depressive symptoms in a Japanese working population: a cross-sectional study. BMC Psychiatry 2014; 14:203. [PMID: 25079305 PMCID: PMC4261564 DOI: 10.1186/1471-244x-14-203] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 07/09/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Leptin and ghrelin have been implicated in the pathogenesis of major depression. However, evidence is lacking among apparently healthy people. This study examined the relationship of these appetite hormones to depressive symptoms in a Japanese working population. METHODS A cross-sectional study was conducted in 2009 among 497 Japanese employees (287 men and 210 women) aged 20-68 years. Fasting serum leptin and ghrelin levels were measured using a Luminex suspension bead-based multiplexed array. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression analysis was performed to estimate odds ratio (OR) and 95% confidence interval (CI) for depressive symptoms with adjustment for potential confounders. RESULTS The prevalence of depressive symptoms (CES-D ≥16) was 26.5% and 33.3% among men and women, respectively. Women in the middle and highest tertiles of leptin levels showed lower odds for depressive symptoms compared with those in the lowest level, although the trend association was not statistically significant (Ptrend = 0.14). Higher ghrelin levels were associated with increased odds for depressive symptoms in women (Ptrend = 0.02). The multivariable adjusted OR (95% CI) of having depressive symptoms for the lowest through highest tertiles of ghrelin levels were 1.00 (reference), 1.71 (0.76 - 3.86), and 2.69 (1.16 - 6.28), respectively. Neither leptin nor ghrelin was associated with depressive symptoms in men. CONCLUSIONS Results suggest that lower leptin and higher ghrelin levels may be related to higher prevalence of depressive status among Japanese women.
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Affiliation(s)
- Shamima Akter
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan.
| | - Ngoc Minh Pham
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan
| | - Akiko Nanri
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan
| | - Kayo Kurotani
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan
| | - Keisuke Kuwahara
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan
| | - Felice N Jacka
- IMPACT Strategic Research Centre, Deakin University, Melbourne, Australia
| | - Kazuki Yasuda
- Department of Metabolic Disorder, Diabetes Research Center, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Masao Sato
- Department of Applied Biological Chemistry, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Tetsuya Mizoue
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Toyama 1-21-1, 162-8655 Shinjuku-ku, Tokyo, Japan
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Braegger FE, Asarian L, Dahl K, Lutz TA, Boyle CN. The role of the area postrema in the anorectic effects of amylin and salmon calcitonin: behavioral and neuronal phenotyping. Eur J Neurosci 2014; 40:3055-66. [PMID: 25040689 DOI: 10.1111/ejn.12672] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 11/27/2022]
Abstract
Amylin reduces meal size by activating noradrenergic neurons in the area postrema (AP). Neurons in the AP also mediate the eating-inhibitory effects of salmon calcitonin (sCT), a potent amylin agonist, but the phenotypes of the neurons mediating its effect are unknown. Here we investigated whether sCT activates similar neuronal populations to amylin, and if its anorectic properties also depend on AP function. Male rats underwent AP lesion (APX) or sham surgery. Meal patterns were analysed under ad libitum and post-deprivation conditions. The importance of the AP in mediating the anorectic action of sCT was examined in feeding experiments of dose-response effects of sCT in APX vs. sham rats. The effect of sCT to induce Fos expression was compared between surgery groups, and relative to amylin. The phenotype of Fos-expressing neurons in the brainstem was examined by testing for the co-expression of dopamine beta hydroxylase (DBH) or tryptophan hydroxylase (TPH). By measuring the apposition of vesicular glutamate transporter-2 (VGLUT2)-positive boutons, potential glutamatergic input to amylin- and sCT-activated AP neurons was compared. Similar to amylin, an intact AP was necessary for sCT to reduce eating. Further, co-expression between Fos activation and DBH after amylin or sCT did not differ markedly, while co-localization of Fos and TPH was minor. Approximately 95% of neurons expressing Fos and DBH after amylin or sCT treatment were closely apposed to VGLUT2-positive boutons. Our study suggests that the hindbrain pathways engaged by amylin and sCT share many similarities, including the mediation by AP neurons.
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Affiliation(s)
- Fiona E Braegger
- Institute of Veterinary Physiology, University of Zurich, Zurich, 8057, Switzerland
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32
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Mithila MV, Khanum F. The appetite regulatory effect of guggulsterones in rats: a repertoire of plasma hormones and neurotransmitters. J Diet Suppl 2014; 11:262-71. [PMID: 25025986 DOI: 10.3109/19390211.2014.937045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Guggulsterone or guggulipid is a steroidal constituent present in the neutral fraction of gum resin of Commiphora mukul, commonly known as guggul. The traditional uses of guggul-resin extract are well documented in the Ayurveda-where it is prescribed to treat a variety of ailments including lipid-related disorders such as obesity and arteriosclerosis. The hypolipidemic activity of the extracts known since ancient times can be traced to the two closely related steroidal ketones, E-guggulsterone and Z-guggulsterone. In this study, we have investigated the dose dependent (100, 200, 400 mg/kg body weight) effect of guggulsterones on appetite regulating hormones [ghrelin, leptin, cholecystokinin (CCK)] and neurotransmitters (serotonin and dopamine), which play a major role in the energy homeostasis and thus influence obesity related factors. We have also studied its effect on food intake, body weight and plasma triglycerides and glucose in rats. Guggulsterones at the dose of 400 mg/kg body weight was able to significantly reduce food intake and limit body weight gain over a period of 15 days. It also significantly decreased the plasma ghrelin, glucose, triglyceride levels and increased plasma leptin, serotonin, dopamine levels, but did not show much effect on CCK levels.
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Affiliation(s)
- M V Mithila
- Biochemistry and Nanosciences Discipline, Defence Food Research Laboratory (DFRL) , Siddhartanagar, Mysore , India
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33
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Hansson C, Alvarez-Crespo M, Taube M, Skibicka KP, Schmidt L, Karlsson-Lindahl L, Egecioglu E, Nissbrandt H, Dickson SL. Influence of ghrelin on the central serotonergic signaling system in mice. Neuropharmacology 2014; 79:498-505. [DOI: 10.1016/j.neuropharm.2013.12.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 11/22/2013] [Accepted: 12/14/2013] [Indexed: 02/09/2023]
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Atalayer D, Astbury NM. Anorexia of aging and gut hormones. Aging Dis 2013; 4:264-75. [PMID: 24124632 DOI: 10.14336/ad.2013.0400264] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 08/02/2013] [Accepted: 08/02/2013] [Indexed: 12/20/2022] Open
Abstract
We are expected to live longer than if we had been born 100 years ago however, the additional years are not necessarily spent in good health or free from disability. Body composition changes dramatically over the course of life. There is a gradual increase in body weight throughout adult life until the age of about 60-65 years. In contrast, body weight appears to decrease with age after the age of 65-75 years, even in those demonstrating a previous healthy body weight. This age related decrease in body weight, often called unintentional weight loss or involuntary weight loss can be a significant problem for the elderly. This has been shown to be related to decline in appetite and food intake is common amongst the elderly and is often referred to the anorexia of aging. Underlying mechanisms regulate energy homeostasis and appetite may change as people age. In this review, peripheral factors regulating appetite have been summarized in regards to their age-dependent changes and role in the etiology of anorexia of aging. Understanding the alterations in the mechanisms regulating appetite and food intake in conjunction with aging may help inform strategies that promote healthy aging and promote health and wellbeing in the elderly years, with the end goal to add life to the years and not just years to our lives.
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Affiliation(s)
- Deniz Atalayer
- Department of Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, NY 10025, USA ; Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke's-Roosevelt Hospital, New York, NY 10025, USA
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Schellekens H, Dinan TG, Cryan JF. Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward. Front Neurosci 2013; 7:148. [PMID: 24009547 PMCID: PMC3757321 DOI: 10.3389/fnins.2013.00148] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/01/2013] [Indexed: 12/25/2022] Open
Abstract
The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense "comfort-foods" and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs.
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A behavioral-genetic investigation of bulimia nervosa and its relationship with alcohol use disorder. Psychiatry Res 2013; 208:232-7. [PMID: 23790978 PMCID: PMC3736835 DOI: 10.1016/j.psychres.2013.04.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 01/25/2013] [Accepted: 04/30/2013] [Indexed: 01/08/2023]
Abstract
Bulimia nervosa (BN) and alcohol use disorder (AUD) frequently co-occur and may share genetic factors; however, the nature of their association is not fully understood. We assessed the extent to which the same genetic and environmental factors contribute to liability to BN and AUD. A bivariate structural equation model using a Cholesky decomposition was fit to data from 7241 women who participated in the Swedish Twin study of Adults: Genes and Environment. The proportion of variance accounted for by genetic and environmental factors for BN and AUD and the genetic and environmental correlations between these disorders were estimated. In the best-fitting model, the heritability estimates were 0.55 (95% CI: 0.37; 0.70) for BN and 0.62 (95% CI: 0.54; 0.70) for AUD. Unique environmental factors accounted for the remainder of variance for BN. The genetic correlation between BN and AUD was 0.23 (95% CI: 0.01; 0.44), and the correlation between the unique environmental factors for the two disorders was 0.35 (95% CI: 0.08; 0.61), suggesting moderate overlap in these factors. The findings from this investigation provide additional support that some of the same genetic factors may influence liability to both BN and AUD.
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37
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Mechanism and novel therapeutic approaches to wasting in chronic disease. Maturitas 2013; 75:199-206. [PMID: 23664695 DOI: 10.1016/j.maturitas.2013.03.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 11/21/2022]
Abstract
Cachexia is a multifactorial syndrome defined by continuous loss of skeletal muscle mass - with or without loss of fat mass - which cannot be fully reversed by conventional nutritional support and which may lead to progressive functional impairment and increased death risk. Its pathophysiology is characterized by negative protein and energy balance driven by a variable combination of reduced food intake and abnormal metabolism. Muscle wasting is encountered in virtually all chronic disease states in particular during advanced stages of the respective illness. Several pre-clinical and clinical studies are ongoing to ameliorate this clinical problem. The mechanisms of muscle wasting and cachexia in chronic diseases such as cancer, chronic heart failure, chronic obstructive pulmonary disease and chronic kidney disease are described. We discuss therapeutic targets and such potential modulators as appetite stimulants, selective androgen receptor modulators, amino acids and naturally occurring peptide hormones.
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38
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Donovan MH, Tecott LH. Serotonin and the regulation of mammalian energy balance. Front Neurosci 2013; 7:36. [PMID: 23543912 PMCID: PMC3608917 DOI: 10.3389/fnins.2013.00036] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/03/2013] [Indexed: 01/17/2023] Open
Abstract
Maintenance of energy balance requires regulation of the amount and timing of food intake. Decades of experiments utilizing pharmacological and later genetic manipulations have demonstrated the importance of serotonin signaling in this regulation. Much progress has been made in recent years in understanding how central nervous system (CNS) serotonin systems acting through a diverse array of serotonin receptors impact feeding behavior and metabolism. Particular attention has been paid to mechanisms through which serotonin impacts energy balance pathways within the hypothalamus. How upstream factors relevant to energy balance regulate the release of hypothalamic serotonin is less clear, but work addressing this issue is underway. Generally, investigation into the central serotonergic regulation of energy balance has had a predominantly “hypothalamocentric” focus, yet non-hypothalamic structures that have been implicated in energy balance regulation also receive serotonergic innervation and express multiple subtypes of serotonin receptors. Moreover, there is a growing appreciation of the diverse mechanisms through which peripheral serotonin impacts energy balance regulation. Clearly, the serotonergic regulation of energy balance is a field characterized by both rapid advances and by an extensive and diverse set of central and peripheral mechanisms yet to be delineated.
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Affiliation(s)
- Michael H Donovan
- Department of Psychiatry, University of California San Francisco CA, USA
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39
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Ishitobi Y, Kohno K, Kanehisa M, Inoue A, Imanaga J, Maruyama Y, Ninomiya T, Higuma H, Okamoto S, Tanaka Y, Tsuru J, Hanada H, Isogawa K, Akiyoshi J. Serum ghrelin levels and the effects of antidepressants in major depressive disorder and panic disorder. Neuropsychobiology 2013; 66:185-92. [PMID: 22948519 DOI: 10.1159/000339948] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 06/08/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Two opposing models for the action of ghrelin in the behavioral responses to stress were recently proposed. Some studies suggest that an increase in ghrelin contributes to the mechanisms responsible for the development of stress-induced depression and anxiety, while others suggest that it helps minimize what otherwise would be more severe manifestations of depression and anxiety following stress. METHODS We measured serum ghrelin levels, Profile of Mood States (POMS) scores and State-Trait Anxiety Inventory scores in nonresponders (treatment-resistant patients; 30) and responders (38) with major depressive disorder (MDD), nonresponders (29) and responders (51) with panic disorder and 97 healthy controls. RESULTS The ghrelin concentration in nonresponders with MDD was higher than that of responders with MDD and normal controls. The ghrelin concentration in nonresponders with panic disorder was higher than that of normal controls. POMS vigor scores in patients with MDD and panic disorder were significantly decreased compared with those in healthy controls. Other POMS scores in patients with MDD and panic disorder were significantly increased compared with those of healthy controls. Trait and state anxiety of the State-Trait Anxiety Inventory in MDD and panic disorder patients were higher than those in healthy controls. CONCLUSIONS These results indicate that decreased serum ghrelin levels might be associated with antidepressant treatment to confer the maximum therapeutic effect in patients with MDD and panic disorder.
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Affiliation(s)
- Yoshinobu Ishitobi
- Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita, Japan
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40
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Raimondo S, Ronchi G, Geuna S, Pascal D, Reano S, Filigheddu N, Graziani A. Ghrelin: a novel neuromuscular recovery promoting factor? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 108:207-21. [PMID: 24083436 DOI: 10.1016/b978-0-12-410499-0.00008-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Promoting neuromuscular recovery after neural injury is a major clinical issue. While techniques for nerve reconstruction are continuously improving and most peripheral nerve lesions can be repaired today, recovery of the lost function is usually unsatisfactory. This evidence claims for innovative nonsurgical therapeutic strategies that can implement the outcome after neural repair. Although no pharmacological approach for improving posttraumatic neuromuscular recovery has still entered clinical practice, various molecules are explored in experimental models of neural repair. One of such molecules is the circulating peptide hormone ghrelin. This hormone has proved to have a positive effect on neural repair after central nervous system lesion, and very recently its effectiveness has also been demonstrated in preventing posttraumatic skeletal muscle atrophy. By contrast, no information is still available about its effectiveness on peripheral nerve regeneration although preliminary data from our laboratory suggest that this molecule can have an effect also in promoting axonal regeneration after nerve injury and repair. Should this be confirmed, ghrelin might represent an ideal candidate as a therapeutic agent for improving posttraumatic neuromuscular recovery because of its putative effects at all the various structural levels involved in this regeneration process, namely, the central nervous system, the peripheral nerve, and the target skeletal muscle.
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Affiliation(s)
- Stefania Raimondo
- Department of Clinical and Biological Sciences, University of Turin & Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
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41
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Schellekens H, van Oeffelen WEPA, Dinan TG, Cryan JF. Promiscuous dimerization of the growth hormone secretagogue receptor (GHS-R1a) attenuates ghrelin-mediated signaling. J Biol Chem 2012; 288:181-91. [PMID: 23161547 DOI: 10.1074/jbc.m112.382473] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
G protein-coupled receptors (GPCRs), such as the ghrelin receptor (GHS-R1a), the melanocortin 3 receptor (MC(3)), and the serotonin 2C receptor (5-HT(2C)), are well known for their key role in the homeostatic control of food intake and energy balance. Ghrelin is the only known gut peptide exerting an orexigenic effect and has thus received much attention as an anti-obesity drug target. In addition, recent data have revealed a critical role for ghrelin in dopaminergic mesolimbic circuits involved in food reward signaling. This study investigates the downstream signaling consequences and ligand-mediated co-internalization following heterodimerization of the GHS-R1a receptor with the dopamine 1 receptor, as well as that of the GHS-R1a-MC(3) heterodimer. In addition, a novel heterodimer between the GHS-R1a receptor and the 5-HT(2C) receptor was identified. Interestingly, dimerization of the GHS-R1a receptor with the unedited 5-HT(2C)-INI receptor, but not with the partially edited 5-HT(2C)-VSV isoform, significantly reduced GHS-R1a agonist-mediated calcium influx, which was completely restored following pharmacological blockade of the 5-HT(2C) receptor. These results combined suggest a potential novel mechanism for fine-tuning GHS-R1a receptor-mediated activity via promiscuous dimerization of the GHS-R1a receptor with other G protein-coupled receptors involved in appetite regulation and food reward. These findings may uncover novel mechanisms of significant relevance for the future pharmacological targeting of the GHS-R1a receptor in the homeostatic regulation of energy balance and in hedonic appetite signaling, both of which play a significant role in the development of obesity.
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Kirsz K, Zieba DA. A review on the effect of the photoperiod and melatonin on interactions between ghrelin and serotonin. Gen Comp Endocrinol 2012; 179:248-53. [PMID: 22974511 DOI: 10.1016/j.ygcen.2012.08.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/07/2012] [Accepted: 08/23/2012] [Indexed: 12/21/2022]
Abstract
Ghrelin and serotonin, which exhibit rhythmic secretion profiles under feeding/fasting conditions, are sensitive to increases and decreases in the day length and form a close web of interrelationships in the regulation of energy homeostasis. Ghrelin and serotonin are biochemically and functionally linked to the suprachiasmatic nucleus, which is a circadian pacemaker, and melatonin, which is an internal transducer of photic environmental changes. Ghrelin and serotonin might be candidates for integrating photic and nonphotic signals, such as light and food availability in the central nervous system. The mechanisms that convert a light signal into a variety of physiological and behavioral rhythms remain unknown. However, we know that the conversion of light signals is necessary to maximize an animal's chances of survival and reproduction.
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Affiliation(s)
- Katarzyna Kirsz
- Department of Swine and Small Ruminant Breeding, Laboratory of Genomics and Biotechnology, University of Agriculture, Krakow 30-059, Poland
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43
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Carlini VP, Machado DG, Buteler F, Ghersi M, Ponzio MF, Martini AC, Schiöth HB, de Cuneo MF, Rodrigues ALS, de Barioglio SR. Acute ghrelin administration reverses depressive-like behavior induced by bilateral olfactory bulbectomy in mice. Peptides 2012; 35:160-5. [PMID: 22525660 DOI: 10.1016/j.peptides.2012.03.031] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/26/2012] [Accepted: 03/26/2012] [Indexed: 11/27/2022]
Abstract
This study aims to examine the antidepressant-like action of Ghrelin (Ghr), a hormone synthesized predominantly by gastrointestinal endocrine cells and released during periods of negative energy balance, in two behavioral models: tail suspension test (TST), a predictive model of antidepressant activity, and the olfactory bulbectomy (OB), an established animal model of depression. The reduction in the immobility time in the TST was the parameter used to assess antidepressant-like effect of Ghr. The depressive-like behavior in olfactory bulbectomized mice was inferred through the increase in the immobility time in the TST and the hyperlocomotor activity in the open-field test. Ghr produced antidepressant-like effect in TST (0.3 nmol/μl, i.c.v.), and reversed OB-induced depressive-like behavior. In conclusion, these results provide clear evidence that an acute administration of ghrelin produce antidepressant-like effect in the TST and OB.
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Affiliation(s)
- Valeria Paola Carlini
- Cátedra de Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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Lawson EA, Miller KK, Blum JI, Meenaghan E, Misra M, Eddy KT, Herzog DB, Klibanski A. Leptin levels are associated with decreased depressive symptoms in women across the weight spectrum, independent of body fat. Clin Endocrinol (Oxf) 2012; 76:520-5. [PMID: 21781144 PMCID: PMC3296868 DOI: 10.1111/j.1365-2265.2011.04182.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Leptin is anorexigenic, and levels are markedly decreased in women with low body weight and high in women with obesity. Ghrelin opposes leptin effects on appetite and is negatively associated with body mass index. These appetite-regulating hormones may have opposing effects on mood and stress pathways. Women with anorexia nervosa (AN), hypothalamic amenorrhoea (HA) and obesity are at increased risk of depression and anxiety. It is unknown whether dysregulation of leptin or ghrelin contributes to the development of depression and/or anxiety in these disorders. We investigated the relationship between leptin and ghrelin levels and symptoms of depression, anxiety and perceived stress in women across the weight spectrum. DESIGN Cross-sectional. PATIENTS 64 women: 15 with AN, 12 normal-weight with HA, 17 overweight or obese (OB) and 20 normal-weight in good health (HC). MEASUREMENTS Fasting serum leptin and plasma ghrelin levels were measured. Hamilton Rating Scales for Depression (HAM-D) and Anxiety (HAM-A) and the Perceived Stress Scale were administered. RESULTS Leptin levels were inversely associated with HAM-D, HAM-A and Perceived Stress scores. The negative relationships between leptin and severity of symptoms of both depression and anxiety remained significant after controlling for body fat or weight. There was no relationship between ghrelin and symptoms of depression or anxiety. Although ghrelin levels were positively associated with the degree of perceived stress, this relationship was not significant after controlling for body fat or weight. CONCLUSIONS Leptin may mediate depressive symptoms across the weight spectrum. Further investigation of the role of leptin in modulating mood will be important.
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Affiliation(s)
- Elizabeth A Lawson
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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45
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Granado M, Fuente-Martín E, García-Cáceres C, Argente J, Chowen JA. Leptin in early life: a key factor for the development of the adult metabolic profile. Obes Facts 2012; 5:138-50. [PMID: 22433625 DOI: 10.1159/000336967] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 10/27/2011] [Indexed: 01/21/2023] Open
Abstract
Leptin levels during the perinatal period are important for the development of metabolic systems involved in energy homeostasis. In rodents, there is a postnatal leptin surge, with circulating leptin levels increasing around postnatal day (PND) 5 and peaking between PND 9 and PND 10. At this time circulating leptin acts as an important trophic factor for the development of hypothalamic circuits that control energy homeostasis and food seeking and reward behaviors. Blunting the postnatal leptin surge results in long-term leptin insensitivity and increased susceptibility to diet-induced obesity during adulthood. Pharmacologically increased leptin levels in the postnatal period also have long-term effects on metabolism. Nevertheless, this effect is controversial as postnatal hyperleptinemia is reported to both increase and decrease the predisposition to obesity in adulthood. The different effects reported in the literature could be explained by the different moments at which this hormone was administered, suggesting that modifications of the neonatal leptin surge at specific time points could selectively affect the development of central and peripheral systems that are undergoing modifications at this moment resulting in different metabolic and behavioral outcomes. In addition, maternal nutrition and the hormonal environment during pregnancy and lactation may also modulate the offspring's response to postnatal modifications in leptin levels. This review highlights the importance of leptin levels during the perinatal period in the development of metabolic systems that control energy homeostasis and how modifications of these levels may induce long-lasting and potentially irreversible effects on metabolism.
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Affiliation(s)
- Miriam Granado
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Department of Pediatrics, Universidad Autónoma de Madrid and CIBER Fisiopatología de Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain.
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Skibicka KP, Dickson SL. Ghrelin and food reward: the story of potential underlying substrates. Peptides 2011; 32:2265-73. [PMID: 21621573 DOI: 10.1016/j.peptides.2011.05.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/11/2011] [Accepted: 05/12/2011] [Indexed: 10/18/2022]
Abstract
The incidence of obesity is increasing at an alarming rate and this worldwide epidemic represents a significant decrease in life span and quality of life of a large part of the affected population. Therefore an understanding of mechanisms underlying food overconsumption and obesity development is urgent and essential to find potential treatments. Research investigating mechanisms underlying obesity and the control of food intake has recently experienced a major shift in focus, from the brain's hypothalamus to additional important neural circuits controlling emotion, cognition and motivated behavior. Among them, the mesolimbic system, and the changes in reward and motivated behavior for food, emerge as new promising treatment targets. Furthermore, there is also growing appreciation of the impact of peripheral hormones that signal nutrition status to the mesolimbic areas, and especially the only known circulating orexigenic hormone, ghrelin. This review article provides a synthesis of recent evidence concerning the impact of manipulation of ghrelin and its receptor on models of food reward/food motivation behavior and the mesolimbic circuitry. Particular attention is given to the potential neurocircuitry and neurotransmitter systems downstream of ghrelin's effects on food reward.
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Affiliation(s)
- Karolina P Skibicka
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 11, SE-405 30 Gothenburg, Sweden.
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Kirsz K, Zieba DA. Ghrelin-mediated appetite regulation in the central nervous system. Peptides 2011; 32:2256-64. [PMID: 21524673 DOI: 10.1016/j.peptides.2011.04.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 11/28/2022]
Abstract
The gut hormone and neuropeptide ghrelin was initially identified in the periphery as a compound released in the bloodstream in response to a negative energetic status. In the central nervous system (CNS), ghrelin mainly acts on the hypothalamus and the limbic system, with its best-known biological role being the regulation of appetitive functions. Recent research has shown that ghrelin is not an indispensable factor in the regulation of food intake. However, it plays a key role in the metabolic changes of lipids, mainly those involving hypothalamic NOS, AMPK, CaMKK2, CPT1 and UCP2 proteins. Ghrelin participates in the regulation of memory processes and the feeling of pleasure resulting from eating, both of which are metabolism-dependent and may be essential for the successful achievement of adaptive appetitive behavior. Ghrelin exerts its biological effect through a complicated network of neuroendocrine links, including the melanocortin and endocannabinoid systems. The activity of ghrelin is connected with circadian and annual fluctuations, which depend on seasons and food availability.
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Affiliation(s)
- Katarzyna Kirsz
- Department of Swine and Small Ruminant Breeding, Laboratory of Genomics and Biotechnology, University of Agriculture, Krakow 30-059, Poland
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Ghersi MS, Casas SM, Escudero C, Carlini VP, Buteler F, Cabrera RJ, Schiöth HB, de Barioglio SR. Ghrelin inhibited serotonin release from hippocampal slices. Peptides 2011; 32:2367-71. [PMID: 21820473 DOI: 10.1016/j.peptides.2011.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/19/2011] [Accepted: 07/19/2011] [Indexed: 10/17/2022]
Abstract
Ghrelin (Ghr) is a peptide produced peripherally and centrally. It participates in the modulation of different biological processes. In our laboratory we have shown that (a) Ghr administration, either intracerebroventricular or directly into the hippocampus enhanced memory consolidation in a step down test in rats (b) the effect of Ghr upon memory decreases in animals pretreated with a serotonin (5-HT) reuptake inhibitor, Fluoxetine, suggesting that Ghr effects in the hippocampus could be related to the availability of 5-HT. It has been demonstrated that Ghr inhibits 5-HT release from rat hypothalamic synaptosomes. Taking in mint these evidences, we studied the release of radioactive 5-HT to the superfusion medium from hippocampal slices treated with two doses of Ghr (0.3 and 3 nm/μl). Ghr inhibited significantly the 5-HT release in relation to those superfused with artificial cerebrospinal fluid (ACSF) (H = 9.48, df = 2, p ≤ 0.05). In another set of experiments, Ghr was infused into the CA1 area of hippocampus of the rats immediately after training in the step down test and the 5-HT release from slices was studied 24h after Ghr injection showing that in this condition also the 5-HT release was inhibited (H = 11.72, df = 1, p ≤ 0.05). In conclusion, results provide additional evidence about the neurobiological bases of Ghr action in hippocampus.
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Affiliation(s)
- Marisa Soledad Ghersi
- Dpto de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IFEC-CONICET, Córdoba, Argentina
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Lutz TA. Steve Woods's contribution to research on amylin's eating inhibitory effect. Physiol Behav 2011; 103:25-30. [DOI: 10.1016/j.physbeh.2010.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/15/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
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Zieba DA, Kirsz K, Molik E, Romanowicz K, Wojtowicz AK. Effects of orexigenic peptides and leptin on melatonin secretion during different photoperiods in seasonal breeding ewes: an in vitro study. Domest Anim Endocrinol 2011; 40:139-46. [PMID: 21185681 DOI: 10.1016/j.domaniend.2010.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 11/26/2022]
Abstract
The pineal gland (PG) acts as a neuroendocrine transducer of daily and seasonal time through the nocturnal release of melatonin. Here, we examined the interaction of season, orexin, ghrelin, and leptin on melatonin secretion by pineal explants in short-term culture. Glands were collected after sunset from 12 ewes during long days (LD; April and May) and from an additional 12 ewes during short days (SD; October and November). Glands were transected sagittally into strips, with each equilibrated in 2.5 mL of Dulbecco's modified Eagle's medium for 60 min, followed by a 2-h incubation in control medium or medium containing orexin B (10 and 100 ng/mL), ghrelin (10 and 100 ng/mL), or 50 ng/mL of leptin. After a 3-h incubation, some PG explants treated previously with lower doses of orexin or ghrelin were challenged with 50 ng/mL of leptin and those treated with both doses of orexin were challenged with 300 nM of the β-agonist isoproterenol. One milliliter of medium was harvested and replaced from each well every 30 min. Treatment with the low dose of orexin during LD increased melatonin secretion about 110% (P<0.01); treatment with a high dose increased melatonin secretion about 47% (P<0.001). During the SD period, leptin stimulated (P < 0.05) melatonin secretion slightly compared with mean melatonin concentration in controls. However, together, orexin and leptin depressed (P<0.01) melatonin secretion. Both doses of ghrelin reduced (P < 0.01) melatonin concentration during the SD season compared with control culture. Addition of ghrelin and leptin to culture medium increased (P<0.01) melatonin concentration compared with ghrelin-treated culture and decreased melatonin concentration (P<0.01) compared with leptin-treated culture during SD. Isoproterenol stimulated (P<0.01) melatonin secretion compared with values observed during the pretreatment period. We conclude that orexigenic peptides (orexin B and ghrelin) and an anorectic peptide (leptin) affect PG directly. The responses of PG to those hormones depend on day length. Moreover, secretion of melatonin from the ovine PG is under an adrenergic regulation.
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Affiliation(s)
- D A Zieba
- Department of Swine and Small Ruminant Breeding, Laboratory of Genomics and Biotechnology, University of Agriculture, Krakow, Poland.
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