1
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Grassi D, Marraudino M, Garcia-Segura LM, Panzica GC. The hypothalamic paraventricular nucleus as a central hub for the estrogenic modulation of neuroendocrine function and behavior. Front Neuroendocrinol 2022; 65:100974. [PMID: 34995643 DOI: 10.1016/j.yfrne.2021.100974] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 12/17/2022]
Abstract
Estradiol and hypothalamic paraventricular nucleus (PVN) help coordinate reproduction with body physiology, growth and metabolism. PVN integrates hormonal and neural signals originating in the periphery, generating an output mediated both by its long-distance neuronal projections, and by a variety of neurohormones produced by its magnocellular and parvocellular neurosecretory cells. Here we review the cyto-and chemo-architecture, the connectivity and function of PVN and the sex-specific regulation exerted by estradiol on PVN neurons and on the expression of neurotransmitters, neuromodulators, neuropeptides and neurohormones in PVN. Classical and non-classical estrogen receptors (ERs) are expressed in neuronal afferents to PVN and in specific PVN interneurons, projecting neurons, neurosecretory neurons and glial cells that are involved in the input-output integration and coordination of neurohormonal signals. Indeed, PVN ERs are known to modulate body homeostatic processes such as autonomic functions, stress response, reproduction, and metabolic control. Finally, the functional implications of the estrogenic modulation of the PVN for body homeostasis are discussed.
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Affiliation(s)
- D Grassi
- Department of Anatomy, Histology and Neuroscience, Universidad Autonoma de Madrid, Madrid, Spain
| | - M Marraudino
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy
| | - L M Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - G C Panzica
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy; Department of Neuroscience Rita Levi Montalcini, University of Torino, Torino, Italy.
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2
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Metz MJ, Daimon CM, King CM, Rau AR, Hentges ST. Individual arcuate nucleus proopiomelanocortin neurons project to select target sites. Am J Physiol Regul Integr Comp Physiol 2021; 321:R982-R989. [PMID: 34755553 PMCID: PMC8714814 DOI: 10.1152/ajpregu.00169.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 11/22/2022]
Abstract
Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARH) are a diverse group of neurons that project widely to different brain regions. It is unknown how this small population of neurons organizes its efferent projections. In this study, we hypothesized that individual ARH POMC neurons exclusively innervate select target regions. To investigate this hypothesis, we first verified that only a fraction of ARH POMC neurons innervate the lateral hypothalamus (LH), the paraventricular nucleus of the hypothalamus (PVN), the periaqueductal gray (PAG), or the ventral tegmental area (VTA) using the retrograde tracer cholera toxin B (CTB). Next, two versions of CTB conjugated to distinct fluorophores were injected bilaterally into two of the regions such that PVN and VTA, PAG and VTA, or LH and PVN received tracers simultaneously. These pairs of target sites were chosen based on function and location. Few individual ARH POMC neurons projected to two brain regions at once, suggesting that there are ARH POMC neuron subpopulations organized by their efferent projections. We also investigated whether increasing the activity of POMC neurons could increase the number of ARH POMC neurons labeled with CTB, implying an increase in new synaptic connections to downstream regions. However, chemogenetic enhancement of POMC neuron activity did not increase retrograde tracing of CTB back to ARH POMC neurons from either the LH, PVN, or VTA. Overall, subpopulations of ARH POMC neurons with distinct efferent projections may serve as a way for the POMC population to organize its many functions.
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Affiliation(s)
- Marissa J Metz
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Caitlin M Daimon
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Connie M King
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Andrew R Rau
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Shane T Hentges
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
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3
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Cavalcanti-de-Albuquerque JP, Donato J. Rolling out physical exercise and energy homeostasis: Focus on hypothalamic circuitries. Front Neuroendocrinol 2021; 63:100944. [PMID: 34425188 DOI: 10.1016/j.yfrne.2021.100944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 01/17/2023]
Abstract
Energy balance is the fine regulation of energy expenditure and energy intake. Negative energy balance causes body weight loss, while positive energy balance promotes weight gain. Modern societies offer a maladapted way of life, where easy access to palatable foods and the lack of opportunities to perform physical activity are considered the roots of the obesity pandemic. Physical exercise increases energy expenditure and, consequently, is supposed to promote weight loss. Paradoxically, physical exercise acutely drives anorexigenic-like effects, but the mechanisms are still poorly understood. Using an evolutionary background, this review aims to highlight the potential involvement of the melanocortin system and other hypothalamic neural circuitries regulating energy balance during and after physical exercise. The physiological significance of these changes will be explored, and possible signalling agents will be addressed. The knowledge discussed here might be important for clarifying obesity aetiology as well as new therapeutic approaches for body weight loss.
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Affiliation(s)
| | - José Donato
- Department of Physiology and Biophysics, University of São Paulo, São Paulo 05508-900, Brazil.
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4
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Quarta C, Claret M, Zeltser LM, Williams KW, Yeo GSH, Tschöp MH, Diano S, Brüning JC, Cota D. POMC neuronal heterogeneity in energy balance and beyond: an integrated view. Nat Metab 2021; 3:299-308. [PMID: 33633406 PMCID: PMC8085907 DOI: 10.1038/s42255-021-00345-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/13/2021] [Indexed: 01/31/2023]
Abstract
Hypothalamic AgRP and POMC neurons are conventionally viewed as the yin and yang of the body's energy status, since they act in an opposite manner to modulate appetite and systemic energy metabolism. However, although AgRP neurons' functions are comparatively well understood, a unifying theory of how POMC neuronal cells operate has remained elusive, probably due to their high level of heterogeneity, which suggests that their physiological roles might be more complex than initially thought. In this Perspective, we propose a conceptual framework that integrates POMC neuronal heterogeneity with appetite regulation, whole-body metabolic physiology and the development of obesity. We highlight emerging evidence indicating that POMC neurons respond to distinct combinations of interoceptive signals and food-related cues to fine-tune divergent metabolic pathways and behaviours necessary for survival. The new framework we propose reflects the high degree of developmental plasticity of this neuronal population and may enable progress towards understanding of both the aetiology and treatment of metabolic disorders.
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Affiliation(s)
- Carmelo Quarta
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, INSERM U1215, Bordeaux, France
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER), Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Lori M Zeltser
- Naomi Berrie Diabetes Center, Columbia University, New York, NY, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Kevin W Williams
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Giles S H Yeo
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität, Munich, Germany
| | - Sabrina Diano
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY, USA
| | - Jens C Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- National Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Daniela Cota
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, INSERM U1215, Bordeaux, France.
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5
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Boyle CN, Le Foll C. Amylin and Leptin interaction: Role During Pregnancy, Lactation and Neonatal Development. Neuroscience 2019; 447:136-147. [PMID: 31846753 DOI: 10.1016/j.neuroscience.2019.11.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 11/08/2019] [Accepted: 11/21/2019] [Indexed: 01/04/2023]
Abstract
Amylin is co-secreted with insulin by pancreatic β-cells in response to a meal and produced by neurons in discrete hypothalamic brain areas. Leptin is proportionally secreted by the adipose tissue. Both hormones control food intake and energy homeostasis post-weaning in rodents. While amylin's main site of action is located in the area postrema (AP) and leptin's is located in the mediobasal hypothalamus, both hormones can also influence the other's signaling pathway; amylin has been shown enhance hypothalamic leptin signaling, and amylin signaling in the AP may rely on functional leptin receptors to modulate its effects. These two hormones also play major roles during other life periods. During pregnancy, leptin levels rise as a result of an increase in fat depot resulting in gestational leptin-resistance to prepare the maternal body for the metabolic needs during fetal development. The role of amylin is far less studied during pregnancy and lactation, though amylin levels seem to be elevated during pregnancy relative to insulin. Whether amylin and leptin interact during pregnancy and lactation remains to be assessed. Lastly, during brain development, amylin and leptin are major regulators of cell birth during embryogenesis and act as neurotrophic factors in the neonatal period. This review will highlight the role of amylin and leptin, and their possible interaction, during these dynamic time periods of pregnancy, lactation, and early development.
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Affiliation(s)
- Christina N Boyle
- Institute of Veterinary Physiology, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland.
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland.
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6
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Romanov RA, Alpár A, Hökfelt T, Harkany T. Unified Classification of Molecular, Network, and Endocrine Features of Hypothalamic Neurons. Annu Rev Neurosci 2019; 42:1-26. [DOI: 10.1146/annurev-neuro-070918-050414] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peripheral endocrine output relies on either direct or feed-forward multi-order command from the hypothalamus. Efficient coding of endocrine responses is made possible by the many neuronal cell types that coexist in intercalated hypothalamic nuclei and communicate through extensive synaptic connectivity. Although general anatomical and neurochemical features of hypothalamic neurons were described during the past decades, they have yet to be reconciled with recently discovered molecular classifiers and neurogenetic function determination. By interrogating magnocellular as well as parvocellular dopamine, GABA, glutamate, and phenotypically mixed neurons, we integrate available information at the molecular, cellular, network, and endocrine output levels to propose a framework for the comprehensive classification of hypothalamic neurons. Simultaneously, we single out putative neuronal subclasses for which future research can fill in existing gaps of knowledge to rationalize cellular diversity through function-determinant molecular marks in the hypothalamus.
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Affiliation(s)
- Roman A. Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Alán Alpár
- Department of Anatomy, Histology, and Embryology, and SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, H-1085 Budapest, Hungary
| | - Tomas Hökfelt
- Department of Neuroscience, Biomedicum, Karolinska Institutet, SE-17165 Stockholm, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
- Department of Neuroscience, Biomedicum, Karolinska Institutet, SE-17165 Stockholm, Sweden
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7
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Shi Z, Cassaglia PA, Pelletier NE, Brooks VL. Sex differences in the sympathoexcitatory response to insulin in obese rats: role of neuropeptide Y. J Physiol 2019; 597:1757-1775. [PMID: 30628058 DOI: 10.1113/jp277517] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 12/20/2018] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Intracerebroventricular insulin increased sympathetic nerve activity (SNA) and baroreflex control of SNA and heart rate more dramatically in obese male rats; in obese females, the responses were abolished. In obese males, the enhanced lumbar SNA (LSNA) responses were associated with reduced tonic inhibition of LSNA by neuropeptide Y (NPY) in the PVN. However, PVN NPY injection decreased LSNA similarly in obesity prone/obesity resistant/control rats. Collectively, these results suggest that NPY inputs were decreased. In obese females, NPY inhibition in the PVN was maintained. Moreover, NPY neurons in the arcuate nucleus became resistant to the inhibitory effects of insulin. A high-fat diet did not alter arcuate NPY neuronal InsR expression in males or females. Obesity-induced 'selective sensitization' of the brain to the sympathoexcitatory effects of insulin and leptin may contribute to elevated basal SNA, and therefore hypertension development, in males with obesity. These data may explain in part why obesity increases SNA less in women compared to men. ABSTRACT Obesity increases sympathetic nerve activity (SNA) in men but not women; however, the mechanisms are unknown. We investigated whether intracerebroventricular insulin infusion increases SNA more in obese male than female rats and if sex differences are mediated by changes in tonic inhibition of SNA by neuropeptide Y (NPY) in the paraventricular nucleus (PVN). When consuming a high-fat diet, obesity prone (OP) rats accrued excess fat, whereas obesity resistant (OR) rats maintained adiposity as in rats eating a control (CON) diet. Insulin increased lumbar SNA (LSNA) similarly in CON/OR males and females under urethane anaesthesia. The LSNA response was magnified in OP males but abolished in OP females. In males, blockade of PVN NPY Y1 receptors with BIBO3304 increased LSNA in CON/OR rats but not OP rats. Yet, PVN nanoinjections of NPY decreased LSNA similarly between groups. Thus, tonic PVN NPY inhibition of LSNA may be lost in obese males as a result of a decrease in NPY inputs. By contrast, in females, PVN BIBO3304 increased LSNA similarly in OP, OR and CON rats. After insulin, PVN BIBO3304 failed to increase LSNA in CON/OR females but increased LSNA in OP females, suggesting that with obesity NPY neurons become resistant to the inhibitory effects of insulin. These sex differences were not associated with changes in arcuate NPY neuronal insulin receptor expression. Collectively, these data reveal a marked sex difference in the impact of obesity on the sympathoexcitatory actions of insulin and implicate sexually dimorphic changes in NPY inhibition of SNA in the PVN as one mechanism.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Priscila A Cassaglia
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Nicole E Pelletier
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
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8
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Wang R, Yuan J, Zhang C, Wang L, Liu Y, Song L, Zhong W, Chen X, Dong J. Neuropeptide Y-Positive Neurons in the Dorsomedial Hypothalamus Are Involved in the Anorexic Effect of Angptl8. Front Mol Neurosci 2018; 11:451. [PMID: 30618603 PMCID: PMC6305345 DOI: 10.3389/fnmol.2018.00451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/21/2018] [Indexed: 12/22/2022] Open
Abstract
Angiopoietin-like protein 8 (Angptl8), a recently identified member of the angiopoietin-like protein family (ANGPTLs), is a 22-kDa peptide synthesized in the liver. It participates in lipid metabolism by inhibiting lipoprotein lipase (LPL) activity, consequently increasing the triglyceride levels. Despite evidence that Angptl8 is involved in feeding control, the underlying mechanisms are unclear. Central and peripheral injections of Angptl8 significantly decreased food intake. Angptl8 was widely expressed in appetite-related nuclei, including the paraventricular nucleus (PVN), the dorsomedial hypothalamus (DMH), the ventromedial hypothalamus, and the arcuate nucleus (ARC) in the hypothalamus. Peripheral Angptl8 administration decreased c-Fos-positive neurons in the DMH. Central Angptl8 administration decreased c-Fos-positive neurons in the DMH and PVN but increased these neurons in the ARC. Angptl8 inhibited appetite via neuropeptide Y (NPY) neurons in the DMH. Furthermore, the chronic administration of Angptl8 decreased body weight gain and altered adipose tissue deposits. Nevertheless, neither peripheral nor central Angptl8 influenced the brown adipose tissue (BAT) morphology or uncoupling protein 1 (Ucp-1) expression in BAT. Taken together, these data suggested that Angptl8 modulates appetite and energy homeostasis.
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Affiliation(s)
- Rui Wang
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Junhua Yuan
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Caishun Zhang
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Liuxin Wang
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Yuan Liu
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Limin Song
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China
| | - Weizhen Zhong
- Institute of Foundation Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xi Chen
- Department of Physiology, Medical College, Qingdao University, Qingdao, China
| | - Jing Dong
- Department of Special Medicine, Medical College, Qingdao University, Qingdao, China.,Department of Physiology, Medical College, Qingdao University, Qingdao, China
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9
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Zhou J, Mao L, Xu P, Wang Y. Effects of (-)-Epigallocatechin Gallate (EGCG) on Energy Expenditure and Microglia-Mediated Hypothalamic Inflammation in Mice Fed a High-Fat Diet. Nutrients 2018; 10:nu10111681. [PMID: 30400620 PMCID: PMC6266769 DOI: 10.3390/nu10111681] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/30/2018] [Accepted: 11/02/2018] [Indexed: 12/28/2022] Open
Abstract
Obesity is an escalating global epidemic caused by an imbalance between energy intake and expenditure. (−)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been reported to be conducive to preventing obesity and alleviating obesity-related chronic diseases. However, the role of EGCG in energy metabolism disorders and central nervous system dysfunction induced by a high-fat diet (HFD) remains to be elucidated. The aim of this study was to evaluate the effects of EGCG on brown adipose tissue (BAT) thermogenesis and neuroinflammation in HFD-induced obese C57BL/6J mice. Mice were randomly divided into four groups with different diets: normal chow diet (NCD), normal chow diet supplemented with 1% EGCG (NCD + EGCG), high-fat diet (HFD), and high-fat diet supplemented with 1% EGCG (HFD + EGCG). Investigations based on a four-week experiment were carried out including the BAT activity, energy consumption, mRNA expression of major inflammatory cytokines in the hypothalamus, nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) phosphorylation, and immunofluorescence staining of microglial marker Iba1 in hypothalamic arcuate nucleus (ARC). Experimental results demonstrated that dietary supplementation of EGCG significantly inhibited HFD-induced obesity by enhancing BAT thermogenesis, and attenuated the hypothalamic inflammation and microglia overactivation by regulating the NF-κB and STAT3 signaling pathways.
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Affiliation(s)
- Jihong Zhou
- Tea Research Institute, Zhejiang University, Hangzhou 310058, China.
| | - Limin Mao
- Tea Research Institute, Zhejiang University, Hangzhou 310058, China.
| | - Ping Xu
- Tea Research Institute, Zhejiang University, Hangzhou 310058, China.
| | - Yuefei Wang
- Tea Research Institute, Zhejiang University, Hangzhou 310058, China.
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10
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Sunstrum JK, Inoue W. Heterosynaptic modulation in the paraventricular nucleus of the hypothalamus. Neuropharmacology 2018; 154:87-95. [PMID: 30408488 DOI: 10.1016/j.neuropharm.2018.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/18/2018] [Accepted: 11/03/2018] [Indexed: 12/21/2022]
Abstract
The stress response-originally described by Hans Selye as "the nonspecific response of the body to any demand made upon it"-is chiefly mediated by the hypothalamic-pituitary-adrenal (HPA) axis and is activated by diverse sensory stimuli that inform threats to homeostasis. The diversity of signals regulating the HPA axis is partly achieved by the complexity of afferent inputs that converge at the apex of the HPA axis: this apex is formed by a group of neurosecretory neurons that synthesize corticotropin-releasing hormone (CRH) in the paraventricular nucleus of the hypothalamus (PVN). The afferent synaptic inputs onto these PVN-CRH neurons originate from a number of brain areas, and PVN-CRH neurons respond to a long list of neurotransmitters/neuropeptides. Considering this complexity, an important question is how these diverse afferent signals independently and/or in concert influence the excitability of PVN-CRH neurons. While many of these inputs directly act on the postsynaptic PVN-CRH neurons for the summation of signals, accumulating data indicates that they also modulate each other's transmission in the PVN. This mode of transmission, termed heterosynaptic modulation, points to mechanisms through which the activity of a specific modulatory input (conveying a specific sensory signal) can up- or down-regulate the efficacy of other afferent synapses (mediating other stress modalities) depending on receptor expression for and spatial proximity to the heterosynaptic signals. Here, we review examples of heterosynaptic modulation in the PVN and discuss its potential role in the regulation of PVN-CRH neurons' excitability and resulting HPA axis activity. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Julia K Sunstrum
- Neuroscience Program, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Wataru Inoue
- Neuroscience Program, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada; Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
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11
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Huang XF, Weston-Green K, Yu Y. Decreased 5-HT2cR and GHSR1a interaction in antipsychotic drug-induced obesity. Obes Rev 2018; 19:396-405. [PMID: 29119689 DOI: 10.1111/obr.12638] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/20/2017] [Accepted: 10/01/2017] [Indexed: 12/19/2022]
Abstract
Second generation antipsychotics (SGAs), notably atypical antipsychotics including olanzapine, clozapine and risperidone, can cause weight gain and obesity side effects. Antagonism of serotonin 2c receptors (5-HT2cR) and activation of ghrelin receptor type 1a (GHSR1a) signalling have been identified as a main cause of SGA induced obesity. Here we review the pivotal regulatory role of the 5-HT2cR in ghrelin-mediated appetite signalling. The 5-HT2cR dimerizes with GHSR1a to inhibit orexigenic signalling, while 5-HT2cR antagonism reduces dimerization and increases GHSR1a-induced food intake. Dimerization is specific to the unedited 5-HT2cR isoform. 5-HT2cR antagonism by SGAs may disrupt the normal inhibitory tone on the GHSR1a, increasing orexigenic signalling. The 5-HT2cR and its interaction with the GHSR1a could serve as the basis for discovering novel approaches to preventing and treating SGA-induced obesity.
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Affiliation(s)
- X-F Huang
- School of Medicine, University of Wollongong and Illawarra Health and Medical Research Institute, NSW, Australia.,Jiangsu Key Laboratory for Immunity and Metabolism, Xuzhou Medical University, Jiangsu, China.,Centre for Medical and Molecular Biosciences, Faculty of Science, Medicine and Health, University of Wollongong, NSW, Australia
| | - K Weston-Green
- School of Medicine, University of Wollongong and Illawarra Health and Medical Research Institute, NSW, Australia.,Centre for Medical and Molecular Biosciences, Faculty of Science, Medicine and Health, University of Wollongong, NSW, Australia
| | - Y Yu
- School of Medicine, University of Wollongong and Illawarra Health and Medical Research Institute, NSW, Australia.,Jiangsu Key Laboratory for Immunity and Metabolism, Xuzhou Medical University, Jiangsu, China
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12
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Abstract
Hypothalamic integration of gastrointestinal and adipose tissue-derived hormones serves as a key element of neuroendocrine control of food intake. Leptin, adiponectin, oleoylethanolamide, cholecystokinin, and ghrelin, to name a few, are in a constant "cross talk" with the feeding-related brain circuits that encompass hypothalamic populations synthesizing anorexigens (melanocortins, CART, oxytocin) and orexigens (Agouti-related protein, neuropeptide Y, orexins). While this integrated neuroendocrine circuit successfully ensures that enough energy is acquired, it does not seem to be equally efficient in preventing excessive energy intake, especially in the obesogenic environment in which highly caloric and palatable food is constantly available. The current review presents an overview of intricate mechanisms underlying hypothalamic integration of energy balance-related peripheral endocrine input. We discuss vulnerabilities and maladaptive neuroregulatory processes, including changes in hypothalamic neuronal plasticity that propel overeating despite negative consequences.
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13
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Abstract
The hypothalamus is an evolutionarily conserved brain structure that regulates an organism's basic functions, such as homeostasis and reproduction. Several hypothalamic nuclei and neuronal circuits have been the focus of many studies seeking to understand their role in regulating these basic functions. Within the hypothalamic neuronal populations, the arcuate melanocortin system plays a major role in controlling homeostatic functions. The arcuate pro-opiomelanocortin (POMC) neurons in particular have been shown to be critical regulators of metabolism and reproduction because of their projections to several brain areas both in and outside of the hypothalamus, such as autonomic regions of the brain stem and spinal cord. Here, we review and discuss the current understanding of POMC neurons from their development and intracellular regulators to their physiological functions and pathological dysregulation.
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Affiliation(s)
- Chitoku Toda
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Anna Santoro
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Jung Dae Kim
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Sabrina Diano
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520; .,Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut 06520.,Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520.,Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520
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14
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New insight into inter-organ crosstalk contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Protein Cell 2017. [PMID: 28643267 PMCID: PMC5818366 DOI: 10.1007/s13238-017-0436-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and a significant global health problem with substantial rise in prevalence over the last decades. It is becoming increasingly clear that NALFD is not only predominantly a hepatic manifestation of metabolic syndrome, but also involves extra-hepatic organs and regulatory pathways. Therapeutic options are limited for the treatment of NAFLD. Accordingly, a better understanding of the pathogenesis of NAFLD is critical for gaining new insight into the regulatory network of NAFLD and for identifying new targets for the prevention and treatment of NAFLD. In this review, we emphasize on the current understanding of the inter-organ crosstalk between the liver and peripheral organs that contributing to the pathogenesis of NAFLD.
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15
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Gomez F, García-García L. Anxiogenic-like effects of fluoxetine render adult male rats vulnerable to the effects of a novel stress. Pharmacol Biochem Behav 2017; 153:32-44. [DOI: 10.1016/j.pbb.2016.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/13/2016] [Accepted: 12/12/2016] [Indexed: 01/25/2023]
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16
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Leon-Mercado L, Herrera Moro Chao D, Basualdo MDC, Kawata M, Escobar C, Buijs RM. The Arcuate Nucleus: A Site of Fast Negative Feedback for Corticosterone Secretion in Male Rats. eNeuro 2017; 4:ENEURO.0350-16.2017. [PMID: 28275717 PMCID: PMC5334455 DOI: 10.1523/eneuro.0350-16.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/05/2017] [Accepted: 02/06/2017] [Indexed: 12/04/2022] Open
Abstract
Variations in circulating corticosterone (Cort) are driven by the paraventricular nucleus of the hypothalamus (PVN), mainly via the sympathetic autonomic nervous system (ANS) directly stimulating Cort release from the adrenal gland and via corticotropin-releasing hormone targeting the adenohypophysis to release adrenocorticotropic hormone (ACTH). Cort feeds back through glucocorticoid receptors (GRs). Here we show in male Wistar rats that PVN neurons projecting to the adrenal gland do not express GRs, leaving the question of how the ANS in the PVN gets information about circulating Cort levels to control the adrenal. Since the arcuate nucleus (ARC) shows a less restrictive blood-brain barrier, expresses GRs, and projects to the PVN, we investigated whether the ARC can detect and produce fast adjustments of circulating Cort. In low Cort conditions (morning), local microdialysis in the ARC with type I GR antagonist produced a fast and sustained increase of Cort. This was not observed with a type II antagonist. At the circadian peak levels of Cort (afternoon), a type II GR antagonist, but not a type I antagonist, increased Cort levels but not ACTH levels. Antagonist infusions in the PVN did not modify circulating Cort levels, demonstrating the specificity of the ARC to give Cort negative feedback. Furthermore, type I and II GR agonists in the ARC prevented the increase of Cort after stress, demonstrating the role of the ARC as sensor to modulate Cort release. Our findings show that the ARC may be essential to sense blood levels of Cort and adapt Cort secretion depending on such conditions as stress or time of day.
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Affiliation(s)
- Luis Leon-Mercado
- Departamento De Biología Celular y Fisiología, Instituto De Investigaciones Biomédicas, Universidad Nacional Autónoma De México, 04510 Mexico City, Mexico
| | - Daniela Herrera Moro Chao
- Department of Medical Biochemistry, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
- Department of Endocrinology and Metabolism, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - María del Carmen Basualdo
- Departamento De Biología Celular y Fisiología, Instituto De Investigaciones Biomédicas, Universidad Nacional Autónoma De México, 04510 Mexico City, Mexico
| | - Mitsuhiro Kawata
- Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
- School of Health Sciences, Bukkyo University, Kyoto 603-8301, Japan
| | - Carolina Escobar
- Departamento De Anatomía, Facultad De Medicina, Universidad Nacional Autónoma De México, 04510 Mexico City, Mexico
| | - Ruud M. Buijs
- Departamento De Biología Celular y Fisiología, Instituto De Investigaciones Biomédicas, Universidad Nacional Autónoma De México, 04510 Mexico City, Mexico
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17
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Wittmann G, Farkas E, Szilvásy-Szabó A, Gereben B, Fekete C, Lechan RM. Variable proopiomelanocortin expression in tanycytes of the adult rat hypothalamus and pituitary stalk. J Comp Neurol 2016; 525:411-441. [PMID: 27503597 DOI: 10.1002/cne.24090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/01/2016] [Accepted: 08/04/2016] [Indexed: 01/21/2023]
Abstract
It is generally believed that proopiomelanocortin (POMC) is expressed exclusively by neurons in the adult rodent brain. Unbeknownst to most researchers, however, Pomc in situ hybridization studies in the rat show specific labeling in the ventral wall of the hypothalamic third ventricle, which is formed by specialized ependymal cells, called tanycytes. Here we characterized this non-neuronal POMC expression in detail using in situ hybridization and immunohistochemical techniques, and report two unique characteristics. First, POMC mRNA and precursor protein expression in non-neuronal cells varies to a great degree as to the extent and abundance of expression. In brains with low-level expression, POMC mRNA and protein was largely confined to a population of tanycytes within the infundibular stalk/caudal median eminence, termed here γ tanycytes, and a subset of closely located β and α2 tanycytes. In brains with high-level expression, POMC mRNA and protein was observed in the vast majority of α2, β, and γ tanycytes. This variability was observed in both adult males and females; of 41 rats between 8 and 15 weeks of age, 17 had low-, 9 intermediate-, and 15 high-level POMC expression in tanycytes. Second, unlike other known POMC-expressing cells, tanycytes rarely contained detectable levels of adrenocorticotropin or α-melanocyte-stimulating hormone. The results indicate either a dynamic spatiotemporal pattern whereby low and high POMC syntheses in tanycytes occur periodically in each brain, or marked interindividual differences that may persist throughout adulthood. Future studies are required to examine these possibilities and elucidate the physiologic importance of POMC in tanycytes. J. Comp. Neurol. 525:411-441, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Gábor Wittmann
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts, 02111
| | - Erzsébet Farkas
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, 1083, Hungary.,Pázmány Péter Catholic University, Multidisciplinary Doctoral School of Sciences and Technology, Budapest, 1083, Hungary
| | - Anett Szilvásy-Szabó
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, 1083, Hungary.,Semmelweis University, János Szentágothai PhD School of Neurosciences, Budapest, 1085, Hungary
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, 1083, Hungary
| | - Csaba Fekete
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts, 02111.,Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, 1083, Hungary
| | - Ronald M Lechan
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts, 02111.,Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111
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18
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Sun J, Gao Y, Yao T, Huang Y, He Z, Kong X, Yu KJ, Wang RT, Guo H, Yan J, Chang Y, Chen H, Scherer PE, Liu T, Williams KW. Adiponectin potentiates the acute effects of leptin in arcuate Pomc neurons. Mol Metab 2016; 5:882-891. [PMID: 27689001 PMCID: PMC5034606 DOI: 10.1016/j.molmet.2016.08.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/08/2016] [Accepted: 08/10/2016] [Indexed: 01/06/2023] Open
Abstract
Objective Adiponectin receptors (AdipoRs) are located on neurons of the hypothalamus involved in metabolic regulation – including arcuate proopiomelanocortin (Pomc) and Neuropeptide Y/Agouti-related peptide (NPY/AgRP) neurons. AdipoRs play a critical role in regulating glucose and fatty acid metabolism by initiating several signaling cascades overlapping with Leptin receptors (LepRs). However, the mechanism by which adiponectin regulates cellular activity in the brain remains undefined. Methods In order to resolve this issue, we utilized neuron-specific transgenic mouse models to identify Pomc and NPY/AgRP neurons which express LepRs for patch-clamp electrophysiology experiments. Results We found that leptin and adiponectin synergistically activated melanocortin neurons in the arcuate nucleus. Conversely, NPY/AgRP neurons were inhibited in response to adiponectin. The adiponectin-induced depolarization of arcuate Pomc neurons occurred via activation of Phosphoinositide-3-kinase (PI3K) signaling, independent of 5′ AMP-activated protein kinase (AMPK) activity. Adiponectin also activated melanocortin neurons at various physiological glucose levels. Conclusions Our results demonstrate a requirement for PI3K signaling in the acute adiponectin-induced effects on the cellular activity of arcuate melanocortin neurons. Moreover, these data provide evidence for PI3K as a substrate for both leptin and adiponectin to regulate energy balance and glucose metabolism via melanocortin activity. Adiponectin activates arcuate Pomc neurons. Adiponectin-induced activation of Pomc neurons requires PI3K (independent of AMPK). Adiponectin inhibits adjacent NPY/AgRP neurons (disinhibiting arcuate Pomc neurons). Leptin potentiates the effects of adiponectin arcuate Pomc neurons.
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Affiliation(s)
- Jia Sun
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Yong Gao
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Ting Yao
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Yiru Huang
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Zhenyan He
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Xingxing Kong
- Division of Endocrinology, Beth Israel Deaconess Medical Center and Harvard Medical School, Harvard University, Boston, MA, 02115, USA
| | - Kai-Jiang Yu
- Department of Intensive Care Unit, The Third Affiliated Hospital, Harbin Medical University, No. 150 Haping St, Nangang District, Harbin, 150081, China
| | - Rui-Tao Wang
- Department of Intensive Care Unit, The Third Affiliated Hospital, Harbin Medical University, No. 150 Haping St, Nangang District, Harbin, 150081, China
| | - Hongbo Guo
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Jianqun Yan
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, China
| | - Yongsheng Chang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hong Chen
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA
| | - Tiemin Liu
- Department of Intensive Care Unit, The Third Affiliated Hospital, Harbin Medical University, No. 150 Haping St, Nangang District, Harbin, 150081, China; Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Kevin W Williams
- Division of Hypothalamic Research, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
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19
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Chitravanshi VC, Kawabe K, Sapru HN. Stimulation of the hypothalamic arcuate nucleus increases brown adipose tissue nerve activity via hypothalamic paraventricular and dorsomedial nuclei. Am J Physiol Heart Circ Physiol 2016; 311:H433-44. [PMID: 27402666 DOI: 10.1152/ajpheart.00176.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 07/01/2016] [Indexed: 11/22/2022]
Abstract
Hypothalamic arcuate nucleus (ARCN) stimulation elicited increases in sympathetic nerve activity (IBATSNA) and temperature (TBAT) of interscapular brown adipose tissue (IBAT). The role of hypothalamic dorsomedial (DMN) and paraventricular (PVN) nuclei in mediating these responses was studied in urethane-anesthetized, artificially ventilated, male Wistar rats. In different groups of rats, inhibition of neurons in the DMN and PVN by microinjections of muscimol attenuated the increases in IBATSNA and TBAT elicited by microinjections of N-methyl-d-aspartic acid into the ipsilateral ARCN. In other groups of rats, blockade of ionotropic glutamate receptors by combined microinjections of D(-)-2-amino-7-phosphono-heptanoic acid (D-AP7) and NBQX into the DMN and PVN attenuated increases in IBATSNA and TBAT elicited by ARCN stimulation. Blockade of melanocortin 3/4 receptors in the DMN and PVN in other groups of rats resulted in attenuation of increases in IBATSNA and TBAT elicited by ipsilateral ARCN stimulation. Microinjections of Fluoro-Gold into the DMN resulted in retrograde labeling of cells in the ipsilateral ARCN, and some of these cells contained proopiomelanocortin (POMC), α-melanocyte-stimulating hormone (α-MSH), or vesicular glutamate transporter-3. Since similar projections from ARCN to the PVN have been reported by us and others, these results indicate that neurons containing POMC, α-MSH, and glutamate project from the ARCN to the DMN and PVN. Stimulation of ARCN results in the release of α-MSH and glutamate in the DMN and PVN which, in turn, cause increases in IBATSNA and TBAT.
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Affiliation(s)
- Vineet C Chitravanshi
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Kazumi Kawabe
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Hreday N Sapru
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
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20
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Habeeballah H, Alsuhaymi N, Stebbing MJ, Jenkins TA, Badoer E. Central leptin and resistin combined elicit enhanced central effects on renal sympathetic nerve activity. Exp Physiol 2016; 101:791-800. [PMID: 27151838 DOI: 10.1113/ep085723] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/03/2016] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Leptin and resistin act centrally to increase renal sympathetic nerve activity (RSNA). We investigated whether a combination of resistin and leptin could induce a greater response than either alone. We also used Fos protein to quantify the number of activated neurons in the brain. What is the main finding and its importance? A combination of leptin and resistin induced a greater increase in RSNA than either hormone alone. This was correlated with a greater number of activated neurons in the arcuate nucleus than with either hormone alone. Leptin and resistin act centrally to increase renal sympathetic nerve activity (RSNA). We investigated whether a combination of resistin and leptin could induce a greater response than either alone. Mean arterial pressure, heart rate and RSNA were recorded before and for 3 h after intracerebroventricular saline (control; n = 5), leptin (7 μg; n = 5), resistin (7 μg; n = 4) and leptin administered 15 min after resistin (n = 6). Leptin alone and resistin alone significantly increased RSNA (74 ± 17 and 50 ± 14%, respectively; P < 0.0001 compared with saline). When leptin and resistin were combined, there was a significantly greater increase in RSNA (163 ± 23%) compared with either hormone alone (P < 0.0001). Maximal responses of mean arterial pressure and heart rate were not significantly different between groups. We also used Fos protein to quantify the number of activated neurons in the brain. Compared with controls, there were significant increases in numbers of Fos-positive neurons in the arcuate and hypothalamic paraventricular nuclei when leptin or resistin was administered alone or when they were combined, and in the lamina terminalis when leptin and resistin were combined. Only in the arcuate nucleus was the increase significantly greater compared with either hormone alone. The findings show that a combination of leptin and resistin induces a greater RSNA increase and a greater number of activated neurons in the arcuate nucleus than with either hormone alone. Given that leptin makes an important contribution to the elevated RSNA observed in obese and overweight conditions, the increased concentrations of leptin and resistin may mean that the contribution of leptin to the elevated RSNA in those conditions is enhanced.
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Affiliation(s)
- Hamza Habeeballah
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Naif Alsuhaymi
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Martin J Stebbing
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Trisha A Jenkins
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Emilio Badoer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
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21
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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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22
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Wang G, Tachibana T, Gilbert ER, Cline MA. Dietary Macronutrient Composition Affects the Influence of Exogenous Prolactin-Releasing Peptide on Appetite Responses and Hypothalamic Gene Expression in Chickens. J Nutr 2015; 145:2406-11. [PMID: 26355003 DOI: 10.3945/jn.115.214338] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/27/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The interaction between the effects of exogenous neurotransmitters and dietary composition on appetite regulation in nonmammalian species is unclear. OBJECTIVE The objective of this study was to determine the effects of exogenous prolactin-releasing peptide (PrRP) and dietary macronutrient composition on food intake regulation in broiler chicks. METHODS Three isocaloric diets were formulated: high-carbohydrate (HC), high-fat (HF; 60% of ME from lard) and high-protein (HP) diets. In Expt. 1, 4-d-old Hubbard × Cobb-500 chicks fed 1 of the 3 diets since hatch were intracerebroventricularly injected with 0 (vehicle), 3, or 188 pmol PrRP (n = 10). Food intake was measured for 180 min. In Expt. 2, hypothalamic mRNA abundance of appetite-associated factors was measured in hypothalamus samples obtained 1 h postinjection of 0 or 188 pmol PrRP. In Expt. 3, chicks were given free access to all diets before and after intracerebroventricular injection and food intake was measured. RESULTS Three and 188 pmol PrRP increased (P = 0.0008 and 0.04) HP diet intake, but only 188 pmol PrRP was efficacious at increasing HC (P = 0.0011) and HF (P = 0.01) consumption compared with the vehicle. There was a diet effect on mRNA abundance of all genes (P < 0.05), with greater expression in chicks fed the HF or HP than the HC diet. Whereas neuropeptide Y (NPY) mRNA was similar between vehicle- and PrRP-injected chicks that consumed HP or HF diets, expression was greater (P < 0.05) in PrRP- than vehicle-injected chicks that consumed the HC diet. When chicks had access to all diets, 188 pmol PrRP caused preferential (P < 0.0001) intake of the HP over the HC and HF diets. CONCLUSION The HP diet enhanced the sensitivity of chicks to the food intake-stimulating effects of PrRP, and PrRP in turn increased preference for the HP diet. Thus, dietary macronutrient composition influences PrRP-mediated food intake, and PrRP in turn affects nutrient intake and transcriptional regulation in chicks.
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Affiliation(s)
- Guoqing Wang
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA; and
| | - Tetsuya Tachibana
- Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, Japan
| | - Elizabeth R Gilbert
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA; and
| | - Mark A Cline
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA; and
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23
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Lam DD, Attard CA, Mercer AJ, Myers MG, Rubinstein M, Low MJ. Conditional expression of Pomc in the Lepr-positive subpopulation of POMC neurons is sufficient for normal energy homeostasis and metabolism. Endocrinology 2015; 156:1292-302. [PMID: 25594696 PMCID: PMC4399319 DOI: 10.1210/en.2014-1373] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Peptides derived from the proopiomelanocortin (POMC) precursor are critical for the normal regulation of many physiological parameters, and POMC deficiency results in severe obesity and metabolic dysfunction. Conversely, augmentation of central nervous system melanocortin function is a promising therapeutic avenue for obesity and diabetes but is confounded by detrimental cardiovascular effects including hypertension. Because the hypothalamic population of POMC-expressing neurons is neurochemically and neuroanatomically heterogeneous, there is interest in the possible dissociation of functionally distinct POMC neuron subpopulations. We used a Cre recombinase-dependent and hypothalamus-specific reactivatable PomcNEO allele to restrict Pomc expression to hypothalamic neurons expressing leptin receptor (Lepr) in mice. In contrast to mice with total hypothalamic Pomc deficiency, which are severely obese, mice with Lepr-restricted Pomc expression displayed fully normal body weight, food consumption, glucose homeostasis, and locomotor activity. Thus, Lepr+ POMC neurons, which constitute approximately two-thirds of the total POMC neuron population, are sufficient for normal regulation of these parameters. This functional dissociation approach represents a promising avenue for isolating therapeutically relevant POMC neuron subpopulations.
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Affiliation(s)
- Daniel D Lam
- Department of Molecular and Integrative Physiology (D.D.L., C.A.A., A.J.M., M.R., M.J.L.), and Department of Internal Medicine (M.G.M.), Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105; and Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (M.R.), Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
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24
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Hodges TE, McCormick CM. Adolescent and adult male rats habituate to repeated isolation, but only adolescents sensitize to partner unfamiliarity. Horm Behav 2015; 69:16-30. [PMID: 25510393 DOI: 10.1016/j.yhbeh.2014.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 11/24/2014] [Accepted: 12/08/2014] [Indexed: 12/29/2022]
Abstract
We investigated whether adolescent male rats show less habituation of corticosterone release than adult male rats to acute vs repeated (16) daily one hour episodes of isolation stress, as well as the role of partner familiarity during recovery on social behavior, plasma corticosterone, and Zif268 expression in brain regions. Adolescents spent more time in social contact than did adults during the initial days of the repeated stress procedures, but both adolescents and adults that returned to an unfamiliar peer after isolation had higher social activity than rats returned to a familiar peer (p=0.002) or undisturbed control rats (p<0.001). Both ages showed evidence of habituation, with reduced corticosterone response to repeated than acute isolation (p=0.01). Adolescents, however, showed sensitized corticosterone release to repeated compared with an acute pairing with an unfamiliar peer during recovery (p=0.03), a difference not found in adults. Consistent with habituation of corticosterone release, the repeated isolation groups had lower Zif268 immunoreactive cell counts in the paraventricular nucleus (p<0.001) and in the arcuate nucleus (p=0.002) than did the acute groups, and adolescents had higher Zif268 immunoreactive cell counts in the paraventricular nucleus than did adults during the recovery period (p<0.001), irrespective of stress history and partner familiarity. Partner familiarity had only modest effects on Zif268 immunoreactivity, and experimental effects on plasma testosterone concentrations were only in adults. The results highlight social and endocrine factors that may underlie the greater vulnerability of the adolescent period of development.
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Affiliation(s)
| | - Cheryl M McCormick
- Department of Psychology, Brock University, Canada; Department of Centre for Neuroscience, Brock University, Canada.
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25
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Roche DJ, King AC. Sex differences in acute hormonal and subjective response to naltrexone: The impact of menstrual cycle phase. Psychoneuroendocrinology 2015; 52:59-71. [PMID: 25459893 PMCID: PMC4482338 DOI: 10.1016/j.psyneuen.2014.10.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/20/2014] [Accepted: 10/13/2014] [Indexed: 11/17/2022]
Abstract
Women often exhibit larger hormonal and subjective responses to opioid receptor antagonists than men, but the biological mechanisms mediating this effect remain unclear. Among women, fluctuations in estradiol (E2) and progesterone (P4) across the menstrual cycle (MC) affect the endogenous opioid system. Therefore, the goal of the current study was to compare acute naltrexone response between women in the early follicular phase of the MC (low E2 and P4), women in the luteal phase of the MC (high E2 and P4), and men. Seventy healthy controls (n=46 women) participated in two morning sessions in which they received 50mg naltrexone or placebo in a randomized, counterbalanced order. Women were randomized to complete both sessions in either the early follicular (n=23) or luteal phase of the MC. Serum cortisol, salivary cortisol, prolactin, luteinizing hormone (LH), and subjective response were assessed upon arrival to the laboratory and at regular intervals after pill administration. In luteal and early follicular women but not men, naltrexone (vs. placebo) increased serum cortisol and prolactin levels from baseline; however, the naltrexone-induced increases in these hormones were significantly greater in luteal women than early follicular women. Additionally, only luteal women demonstrated an increase from baseline in salivary cortisol levels and the severity of adverse drug effects in response to naltrexone. In sum, the results indicate that luteal phase women are more sensitive to acute hormonal and subjective effects of naltrexone than early follicular women and men. These findings may have important implications for the use of naltrexone in women.
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Affiliation(s)
- Daniel J.O. Roche
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Andrea C. King
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, USA
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Wood SK, Bhatnagar S. Resilience to the effects of social stress: evidence from clinical and preclinical studies on the role of coping strategies. Neurobiol Stress 2015; 1:164-173. [PMID: 25580450 PMCID: PMC4286805 DOI: 10.1016/j.ynstr.2014.11.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The most common form of stress encountered by people stems from one's social environment and is perceived as more intense than other types of stressors. One feature that may be related to differential resilience or vulnerability to stress is the type of strategy used to cope with the stressor, either active or passive coping. This review focuses on models of social stress in which individual differences in coping strategies produce resilience or vulnerability to the effects of stress. Neurobiological mechanisms underlying these individual differences are discussed. Overall, the literature suggests that there are multiple neural mechanisms that underlie individual differences in stress-induced resilience and vulnerability. How these mechanisms interact with one another to produce a resilient or vulnerable phenotype is not understood and such mechanisms have been poorly studied in females and in early developmental periods. Finally, we propose that resilience may be stress context specific and resilience phenotypes may need to be fine-tuned to suit a shifting environment. Resilience is considered positive adaptation in the face of adversity. Coping strategy impacts one's susceptibility to social stress-induced psychopathology. Neurobiological substrates such as CRF, NPY and DA may impact stress susceptibility. Individual differences within females and during adolescence are poorly understood.
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Affiliation(s)
- Susan K. Wood
- Department of Pharmacology Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29209, USA
- Corresponding author. Department of Pharmacology, Physiology & Neuroscience, Basic Science Bldg 1, 3rd Floor, Rm D28A, 6439 Garners Ferry Rd, Columbia, SC 29209, USA.
| | - Seema Bhatnagar
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia and the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4399, USA
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Jeong JK, Kim JG, Lee BJ. Participation of the central melanocortin system in metabolic regulation and energy homeostasis. Cell Mol Life Sci 2014; 71:3799-809. [PMID: 24894870 PMCID: PMC11113577 DOI: 10.1007/s00018-014-1650-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/23/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
Abstract
Obesity and metabolic disorders, such as type 2 diabetes and hypertension, have attracted considerable attention as life-threatening diseases not only in developed countries but also worldwide. Additionally, the rate of obesity in young people all over the world is rapidly increasing. Accumulated evidence suggests that the central nervous system may participate in the development of and/or protection from obesity. For example, in the brain, the hypothalamic melanocortin system senses and integrates central and peripheral metabolic signals and controls the degree of energy expenditure and feeding behavior, in concert with metabolic status, to regulate whole-body energy homeostasis. Currently, researchers are studying the mechanisms by which peripheral metabolic molecules control feeding behavior and energy balance through the central melanocortin system. Accordingly, recent studies have revealed that some inflammatory molecules and transcription factors participate in feeding behavior and energy balance by controlling the central melanocortin pathway, and have thus become new candidates as therapeutic targets to fight metabolic diseases such as obesity and diabetes.
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Affiliation(s)
- Jin Kwon Jeong
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77004 USA
| | - Jae Geun Kim
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan, 680-749 South Korea
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Wood SK. Cardiac autonomic imbalance by social stress in rodents: understanding putative biomarkers. Front Psychol 2014; 5:950. [PMID: 25206349 PMCID: PMC4143725 DOI: 10.3389/fpsyg.2014.00950] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 08/10/2014] [Indexed: 12/17/2022] Open
Abstract
Exposure to stress or traumatic events can lead to the development of depression and anxiety disorders. In addition to the debilitating consequences on mental health, patients with psychiatric disorders also suffer from autonomic imbalance, making them susceptible to a variety of medical disorders. Emerging evidence utilizing spectral analysis of heart rate variability (HRV), a reliable non-invasive measure of cardiovascular autonomic regulation, indicates that patients with depression and various anxiety disorders (i.e., panic, social, generalized anxiety disorders, and post traumatic stress disorder) are characterized by decreased HRV. Social stressors in rodents are ethologically relevant experimental stressors that recapitulate many of the dysfunctional behavioral and physiological changes that occur in psychological disorders. In this review, evidence from clinical studies and preclinical stress models identify putative biomarkers capable of precipitating the comorbidity between disorders of the mind and autonomic dysfunction. Specifically, the role of corticotropin releasing factor, neuropeptide Y and inflammation are investigated. The impetus for this review is to highlight stress-related biomarkers that may prove critical in the development of autonomic imbalance in stress -related psychiatric disorders.
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Affiliation(s)
- Susan K Wood
- Department of Pharmacology, Physiology and Neuroscience, School of Medicine, University of South Carolina Columbia, SC, USA
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Foo KS, Hellysaz A, Broberger C. Expression and colocalization patterns of calbindin-D28k, calretinin and parvalbumin in the rat hypothalamic arcuate nucleus. J Chem Neuroanat 2014; 61-62:20-32. [PMID: 25014433 DOI: 10.1016/j.jchemneu.2014.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/26/2014] [Accepted: 06/26/2014] [Indexed: 11/16/2022]
Abstract
Calcium binding proteins (CaBPs) form a diverse group of molecules that function as signal transducers or as intracellular buffers of Ca(2+) concentration. They have been extensively used to histochemically categorize cell types throughout the brain. One region which has not yet been characterized with regard to CaBP expression is the hypothalamic arcuate nucleus, which plays a vital role in neuroendocrine control and the central regulation of energy metabolism. Using in situ hybridization and immunofluorescence, we have investigated the cellular distribution of the three CaBPs, calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV) in the rat arcuate nucleus. Both mRNA and immunoreactivity was detected in the arcuate nucleus for CB - located in the medial aspects - and CR - located ventrolaterally. No PV mRNA was detected in the arcuate nucleus. Immunofluorescence results for PV were ambiguous; while one antibody detected a group of cell somata, a different antibody failed to visualize any arcuate nucleus cell profiles. Using double-labeling, neither of the examined CaBPs were observed in cells immunoreactive for the signaling molecules agouti gene-related protein, tyrosine hydroxylase, neurotensin, growth hormone-releasing hormone, somatostatin, enkephalin, dynorphin or galanin. We did, however, observe CB- and CR-immunoreactivity, in two distinct populations of neurons immunoreactive for the melanocortin peptide α-melanocyte-stimulating hormone. These data identify distinct subpopulations of arcuate neurons defined by their expression of CaBPs and provide further support for differentiation between subpopulations of anorexigenic melanocortin neurons.
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Affiliation(s)
- Kylie S Foo
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Arash Hellysaz
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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The neuroanatomical function of leptin in the hypothalamus. J Chem Neuroanat 2014; 61-62:207-20. [PMID: 25007719 DOI: 10.1016/j.jchemneu.2014.05.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 05/09/2014] [Accepted: 05/28/2014] [Indexed: 02/07/2023]
Abstract
The anorexigenic hormone leptin plays an important role in the control of food intake and feeding-related behavior, for an important part through its action in the hypothalamus. The adipose-derived hormone modulates a complex network of several intercommunicating orexigenic and anorexigenic neuropeptides in the hypothalamus to reduce food intake and increase energy expenditure. In this review we present an updated overview of the functional role of leptin in respect to feeding and feeding-related behavior per distinct hypothalamic nuclei. In addition to the arcuate nucleus, which is a major leptin sensitive hub, leptin-responsive neurons in other hypothalamic nuclei, including the, dorsomedial-, ventromedial- and paraventricular nucleus and the lateral hypothalamic area, are direct targets of leptin. However, leptin also modulates hypothalamic neurons in an indirect manner, such as via the melanocortin system. The dissection of the complexity of leptin's action on the networks involved in energy balance is subject of recent and future studies. A full understanding of the role of hypothalamic leptin in the regulation of energy balance requires cell-specific manipulation using of conditional deletion and expression of leptin receptors. In addition, optogenetic and pharmacogenetic tools in combination with other pharmacological (such as the recent discovery of a leptin receptor antagonist) and neuronal tracing techniques to map the circuit, will be helpful to understand the role of leptin receptor expressing neurons. Better understanding of these circuits and the involvement of leptin could provide potential sites for therapeutic interventions in obesity and metabolic diseases characterized by dysregulation of energy balance.
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Tsai VWW, Manandhar R, Jørgensen SB, Lee-Ng KKM, Zhang HP, Marquis CP, Jiang L, Husaini Y, Lin S, Sainsbury A, Sawchenko PE, Brown DA, Breit SN. The anorectic actions of the TGFβ cytokine MIC-1/GDF15 require an intact brainstem area postrema and nucleus of the solitary tract. PLoS One 2014; 9:e100370. [PMID: 24971956 PMCID: PMC4074070 DOI: 10.1371/journal.pone.0100370] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 05/27/2014] [Indexed: 12/26/2022] Open
Abstract
Macrophage inhibitory cytokine-1 (MIC-1/GDF15) modulates food intake and body weight under physiological and pathological conditions by acting on the hypothalamus and brainstem. When overexpressed in disease, such as in advanced cancer, elevated serum MIC-1/GDF15 levels lead to an anorexia/cachexia syndrome. To gain a better understanding of its actions in the brainstem we studied MIC-1/GDF15 induced neuronal activation identified by induction of Fos protein. Intraperitoneal injection of human MIC-1/GDF15 in mice activated brainstem neurons in the area postrema (AP) and the medial (m) portion of the nucleus of the solitary tract (NTS), which did not stain with tyrosine hydroxylase (TH). To determine the importance of these brainstem nuclei in the anorexigenic effect of MIC-1/GDF15, we ablated the AP alone or the AP and the NTS. The latter combined lesion completely reversed the anorexigenic effects of MIC-1/GDF15. Altogether, this study identified neurons in the AP and/or NTS, as being critical for the regulation of food intake and body weight by MIC-1/GDF15.
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Affiliation(s)
- Vicky Wang-Wei Tsai
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Rakesh Manandhar
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | | | - Ka Ki Michelle Lee-Ng
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Hong Ping Zhang
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher Peter Marquis
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Lele Jiang
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Yasmin Husaini
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Shu Lin
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Amanda Sainsbury
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, New South Wales, Australia
| | - Paul E. Sawchenko
- Laboratory of Neuronal Structure and Function, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - David A. Brown
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
| | - Samuel N. Breit
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital and University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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Wood SK. Individual differences in the neurobiology of social stress: implications for depression-cardiovascular disease comorbidity. Curr Neuropharmacol 2014; 12:205-11. [PMID: 24669213 PMCID: PMC3964750 DOI: 10.2174/1570159x11666131120224413] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/02/2013] [Accepted: 11/02/2013] [Indexed: 12/16/2022] Open
Abstract
Stress initiates a cascade of complex neural and peripheral changes that promote healthy adaption to stress, but when unabated, leads to pathology. Fascinating individual differences arise in the ability to cope with a stressor, rendering an individual more or less likely to develop stress-induced pathologies such as depression, anxiety, and cardiovascular disease. In this review we evaluate recent findings that investigate the neural underpinnings of adopting a passive or active coping response during social defeat stress. Because passive coping is associated with vulnerability to stress-related pathologies and active coping confers resiliency, understanding neurobiological adaptations associated with these diverse coping strategies may reveal biomarkers or targets impacting stress susceptibility. The co-occurrence of stress-induced depression and cardiovascular disease is becoming increasingly clear. Therefore this review focuses on the central mechanisms capable of contributing to psychopathology and cardiovascular disease such as corticotropin releasing factor, neuropeptide Y, monoamines, cytokines and oxidative stress. The impetus for this review is to highlight neurobiological systems that warrant further evaluation for their contribution to the pathophysiology of depression-cardiovascular disease comorbidity.
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Affiliation(s)
- Susan K Wood
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology and Neuroscience
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33
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Di Yorio MP, Bilbao MG, Faletti AG. Neuropeptide Y regulates the leptin receptors in rat hypothalamic and pituitary explant cultures. ACTA ACUST UNITED AC 2014; 188:13-20. [DOI: 10.1016/j.regpep.2013.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 11/05/2013] [Accepted: 11/19/2013] [Indexed: 01/01/2023]
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34
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Sohn JW. Ion channels in the central regulation of energy and glucose homeostasis. Front Neurosci 2013; 7:85. [PMID: 23734095 PMCID: PMC3661948 DOI: 10.3389/fnins.2013.00085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 05/08/2013] [Indexed: 11/23/2022] Open
Abstract
Ion channels are critical regulators of neuronal excitability and synaptic function in the brain. Recent evidence suggests that ion channels expressed by neurons within the brain are responsible for regulating energy and glucose homeostasis. In addition, the central effects of neurotransmitters and hormones are at least in part achieved by modifications of ion channel activity. This review focuses on ion channels and their neuronal functions followed by a discussion of the identified roles for specific ion channels in the central pathways regulating food intake, energy expenditure, and glucose balance.
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Affiliation(s)
- Jong-Woo Sohn
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center Dallas, TX, USA
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35
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Roche DJO, King AC, Cohoon AJ, Lovallo WR. Hormonal contraceptive use diminishes salivary cortisol response to psychosocial stress and naltrexone in healthy women. Pharmacol Biochem Behav 2013; 109:84-90. [PMID: 23672966 DOI: 10.1016/j.pbb.2013.05.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/04/2013] [Accepted: 05/04/2013] [Indexed: 10/26/2022]
Abstract
The use of hormonal contraception (HC) may affect salivary cortisol levels at rest and in response to a pharmacological or stress challenge. Therefore, the current study used a secondary data analysis to investigate the effect of HC on salivary cortisol levels in response to the mu-opioid receptor antagonist naltrexone and a psychosocial stressor, and also across the diurnal curve. Two hundred and nine women (n=72 using hormonal contraception; HC+) completed a two-session stress response study that consisted of a stress day, in which they were exposed to public speaking and mental arithmetic, and a rest day, in which unstimulated cortisol levels were measured to assess the diurnal rhythm. A subset of seventy women (n=24 HC+) also completed a second study in which they were administered oral naltrexone (50mg) or placebo in a randomized, placebo-controlled, double blind fashion. Women who were HC+ had a significantly reduced salivary cortisol response to both the psychosocial stressor (p<0.001) and naltrexone (p<0.05) compared to HC- women. Additionally, HC+ women had a significantly altered morning diurnal cortisol rhythm (p<0.01), with a delayed peak and higher overall levels. The results of the current study confirm that HC attenuates salivary cortisol response to a psychosocial stressor and mu-opioid receptor antagonism, and also alters the morning diurnal cortisol curve.
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Affiliation(s)
- Daniel J O Roche
- Department of Psychiatry and Behavioral Sciences, University of Chicago, Chicago, IL 60637, USA
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36
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The Role of Cholecystokinin Receptors in the Short-Term Control of Food Intake. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:277-316. [DOI: 10.1016/b978-0-12-386933-3.00008-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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37
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38
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Charney DS. The psychobiology of resilience and vulnerability to anxiety disorders: implications for prevention and treatment. DIALOGUES IN CLINICAL NEUROSCIENCE 2012. [PMID: 22034473 PMCID: PMC3181630 DOI: 10.31887/dcns.2003.5.3/dcharney] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Much of the research on the neurobiology of human anxiety disorders has focused on psychopaihological abnormalities in patients with anxiety disorders. While this line of research is obviously important, more investigation is needed to elucidate the psychobiology of resilience to extreme stress. Study of the psychobiology of resilience has the potential to identify neurochemical, neuropeptide, and hormonal mediators of vulnerability and resilience to severe stress. In addition, the relevance of neural mechanisms of reward and motivation, fear responsiveness, and social behavior to character traits associated with risk and resistance to anxiety disorders may be clarified. These areas of investigation should lead to improved methods of diagnosis, novel approaches to prevention, and new targets for antianxiety drug discovery.
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Affiliation(s)
- Dennis S Charney
- Chief, Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, Md, USA
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Costa-e-Sousa RH, Hollenberg AN. Minireview: The neural regulation of the hypothalamic-pituitary-thyroid axis. Endocrinology 2012; 153:4128-35. [PMID: 22759379 PMCID: PMC3423621 DOI: 10.1210/en.2012-1467] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 06/14/2012] [Indexed: 12/20/2022]
Abstract
Thyroid hormone (TH) signaling plays an important role in development and adult life. Many organisms may have evolved under selective pressure of exogenous TH, suggesting that thyroid hormone signaling is phylogenetically older than the systems that regulate their synthesis. Therefore, the negative feedback system by TH itself was probably the first mechanism of regulation of circulating TH levels. In humans and other vertebrates, it is well known that TH negatively regulates its own production through central actions that modulate the hypothalamic-pituitary-thyroid (HPT) axis. Indeed, primary hypothyroidism leads to the up-regulation of the genes encoding many key players in the HPT axis, such as TRH, type 2 deiodinase (dio2), pyroglutamyl peptidase II (PPII), TRH receptor 1 (TRHR1), and the TSH α- and β-subunits. However, in many physiological circumstances, the activity of the HPT axis is not always a function of circulating TH concentrations. Indeed, circadian changes in the HPT axis activity are not a consequence of oscillation in circulating TH levels. Similarly, during reduced food availability, several components of the HPT axis are down-regulated even in the presence of lower circulating TH levels, suggesting the presence of a regulatory pathway hierarchically higher than the feedback system. This minireview discusses the neural regulation of the HPT axis, focusing on both TH-dependent and -independent pathways and their potential integration.
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Affiliation(s)
- Ricardo H Costa-e-Sousa
- Beth Israel Deaconess Medical Center and Harvard Medical School, Division Endocrinology, Diabetes and Metabolism, 330 Brookline Avenue, CLS-0738, Boston, Massachusetts 02215, USA
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Ablation of Sim1 neurons causes obesity through hyperphagia and reduced energy expenditure. PLoS One 2012; 7:e36453. [PMID: 22558467 PMCID: PMC3338647 DOI: 10.1371/journal.pone.0036453] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 04/04/2012] [Indexed: 11/23/2022] Open
Abstract
Single-minded 1 (Sim1) is a transcription factor necessary for development of the paraventricular nucleus of the hypothalamus (PVH). This nucleus is a critical regulator of appetite, energy expenditure and body weight. Previously we showed that Sim1+/− mice and conditional postnatal Sim1−/− mice exhibit hyperphagia, obesity, increased linear growth and susceptibility to diet-induced obesity, but no decrease in energy expenditure. Bilateral ablation of the PVH causes obesity due to hyperphagia and reduced energy expenditure. It remains unknown whether Sim1 neurons regulate energy expenditure. In this study, Sim1cre mice were bred to homozygous inducible diphtheria toxin receptor (iDTR) mice to generate mice expressing the simian DTR in Sim1 cells. In these mice, Sim1 neuron ablation was performed by intracerebroventricular (ICV) injection of diphtheria toxin. Compared to controls, mice with Sim1 neuron ablation became obese (with increased fat mass) on a chow diet due to increased food intake and reduced energy expenditure. In post-injection mice, we observed a strong inverse correlation between the degree of obesity and hypothalamic Sim1 expression. The reduction in baseline energy expenditure observed in these mice was accompanied by a reduction in activity. This reduction in activity did not fully account for the reduced energy expenditure as these mice exhibited decreased resting energy expenditure, decreased body temperature, decreased brown adipose tissue temperature, and decreased UCP1 expression suggesting an impairment of thermogenesis. In injected mice, hypothalamic gene expression of Sim1, oxytocin (OXT) and thyrotropin releasing hormone (TRH) was reduced by about 50%. These results demonstrate that Sim1 neurons in adult mice regulate both food intake and energy expenditure. Based on the body of work in the field, feeding regulation by Sim1 neurons likely occurs in both the PVH and medial amygdala, in contrast to energy expenditure regulation by Sim1 neurons, which likely is localized to the PVH.
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Sainsbury A, Zhang L. Role of the hypothalamus in the neuroendocrine regulation of body weight and composition during energy deficit. Obes Rev 2012; 13:234-57. [PMID: 22070225 DOI: 10.1111/j.1467-789x.2011.00948.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Energy deficit in lean or obese animals or humans stimulates appetite, reduces energy expenditure and possibly also decreases physical activity, thereby contributing to weight regain. Often overlooked in weight loss trials for obesity, however, is the effect of energy restriction on neuroendocrine status. Negative energy balance in lean animals and humans consistently inhibits activity of the hypothalamo-pituitary-thyroid, -gonadotropic and -somatotropic axes (or reduces circulating insulin-like growth factor-1 levels), while concomitantly activating the hypothalamo-pituitary-adrenal axis, with emerging evidence of similar changes in overweight and obese people during lifestyle interventions for weight loss. These neuroendocrine changes, which animal studies show may result in part from hypothalamic actions of orexigenic (e.g. neuropeptide Y, agouti-related peptide) and anorexigenic peptides (e.g. alpha-melanocyte-stimulating hormone, and cocaine and amphetamine-related transcript), can adversely affect body composition by promoting the accumulation of adipose tissue (particularly central adiposity) and stimulating the loss of lean body mass and bone. As such, current efforts to maximize loss of excess body fat in obese people may inadvertently be promoting long-term complications such as central obesity and associated health risks, as well as sarcopenia and osteoporosis. Future weight loss trials would benefit from assessment of the effects on body composition and key hormonal regulators of body composition using sensitive techniques.
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Affiliation(s)
- A Sainsbury
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, NSW, Australia.
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42
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Preston E, Cooney GJ, Wilks D, Baran K, Zhang L, Kraegen EW, Sainsbury A. Central neuropeptide Y infusion and melanocortin 4 receptor antagonism inhibit thyrotropic function by divergent pathways. Neuropeptides 2011; 45:407-15. [PMID: 21862125 DOI: 10.1016/j.npep.2011.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/24/2011] [Accepted: 07/25/2011] [Indexed: 11/24/2022]
Abstract
Weight loss inhibits thyrotropic function and reduces metabolic rate, thereby contributing to weight regain. Under negative energy balance there is an increase in the hypothalamic expression of both neuropeptide Y (NPY) and agouti related peptide (AgRP), the endogenous antagonist of melanocortin 4 (MC4) receptors. Both NPY and MC4 receptor antagonism reduce thyrotropic function centrally, but it is not known whether these pathways operate by similar or distinct mechanisms. We compared the time-course of effects of acute or chronic intracerebroventricular (ICV) administration of NPY (1.2 nmol acute bolus, or 3.5 nmol/day for 6 days) or the MC4 receptor antagonist HS014 (1.5 nmol bolus, or 4.8 nmol/day) on plasma concentrations of thyroid stimulating hormone (TSH) or free thyroxine (T4) in male rats pair-fed with vehicle-infused controls. These doses equipotently induced hyperphagia in acute studies, reduced latency to feed, and increased white adipose tissue mass after 6 days of infusion. Acute central NPY but not HS014 administration significantly reduced plasma TSH concentrations within 30-60 min and plasma free T4 levels within 90-120 min. These inhibitory effects were sustained for up to 5-6 days of continuous NPY infusion. HS014 induced a transient decrease in plasma free T4 levels that was observed only after 1-2 days of continuous ICV infusion. While both NPY and HS014 significantly increased corticosteronemia within an hour after ICV injection, the effect of NPY was significantly more pronounced and was sustained for up to 4 days of administration. Both NPY and HS014 significantly decreased the brown adipose tissue protein levels of uncoupling protein-3. We conclude that central NPY and MC4 antagonism decrease thyrotropic function via partially distinct mechanisms with different time courses, possibly involving glucocorticoid effects of NPY. MC4 receptor antagonism increases adiposity via pathways independent of increased food intake or changes in circulating concentrations of TSH, free T4 or corticosterone.
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Affiliation(s)
- Elaine Preston
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Australia
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43
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Scherer T, Buettner C. Yin and Yang of hypothalamic insulin and leptin signaling in regulating white adipose tissue metabolism. Rev Endocr Metab Disord 2011; 12:235-43. [PMID: 21713385 PMCID: PMC3253350 DOI: 10.1007/s11154-011-9190-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fatty acids released from white adipose tissue (WAT) provide important energy substrates during fasting. However, uncontrolled fatty acid release from WAT during non-fasting states causes lipotoxicity and promotes inflammation and insulin resistance, which can lead to and worsen type 2 diabetes (DM2). WAT is also a source for insulin sensitizing fatty acids such as palmitoleate produced during de novo lipogenesis. Insulin and leptin are two major hormonal adiposity signals that control energy homeostasis through signaling in the central nervous system. Both hormones have been implicated to regulate both WAT lipolysis and de novo lipogenesis through the mediobasal hypothalamus (MBH) in an opposing fashion independent of their respective peripheral receptors. Here, we review the current literature on brain leptin and insulin action in regulating WAT metabolism and discuss potential mechanisms and neuro-anatomical substrates that could explain the opposing effects of central leptin and insulin. Finally, we discuss the role of impaired hypothalamic control of WAT metabolism in the pathogenesis of insulin resistance, metabolic inflexibility and type 2 diabetes.
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Pirnik Z, Bundziková J, Holubová M, Pýchová M, Fehrentz JA, Martinez J, Zelezná B, Maletínská L, Kiss A. Ghrelin agonists impact on Fos protein expression in brain areas related to food intake regulation in male C57BL/6 mice. Neurochem Int 2011; 59:889-95. [PMID: 21843570 DOI: 10.1016/j.neuint.2011.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/27/2011] [Accepted: 08/01/2011] [Indexed: 12/18/2022]
Abstract
Many peripheral substances, including ghrelin, induce neuronal activation in the brain. In the present study, we compared the effect of subcutaneously administered ghrelin and its three stable agonists: Dpr(3)ghr ([Dpr(N-octanoyl)(3)] ghrelin) (Dpr - diaminopropionic acid), YA GHRP-6 (H-Tyr-Ala-His-DTrp-Ala-Trp-DPhe-Lys-NH(2)), and JMV1843 (H-Aib-DTrp-D-gTrp-CHO) on the Fos expression in food intake-responsive brain areas such as the hypothalamic paraventricular (PVN) and arcuate (ARC) nuclei, the nucleus of the solitary tract (NTS), and area postrema (AP) in male C57BL/6 mice. Immunohistochemical analysis showed that acute subcutaneous dose of each substance (5mg/kg b.w.), which induced a significant food intake increase, elevated Fos protein expression in all brain areas studied. Likewise ghrelin, each agonist tested induced distinct Fos expression overall the PVN. In the ARC, ghrelin and its agonists specifically activated similarly distributed neurons. Fos occurrence extended from the anterior (aARC) to middle (mARC) ARC region. In the latter part of the ARC, the Fos profiles were localized bilaterally, especially in the ventromedial portions of the nucleus. In the NTS, all substances tested also significantly increased the number of Fos profiles in neurons, which also revealed specific location, i.e., in the NTS dorsomedial subnucleus (dmNTS) and the area subpostrema (AsP). In addition, cells located nearby the NTS, in the AP, also revealed a significant increase in number of Fos-activated cells. These results demonstrate for the first time that ghrelin agonists, regardless of their different chemical nature, have a significant and similar activating impact on specific groups of neurons that can be a part of the circuits involved in the food intake regulation. Therefore there is a real potency for ghrelin agonists to treat cachexia and food intake disorders. Thus, likewise JMV1843, the other ghrelin agonists represent substances that might be involved in trials for clinical purposes.
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Affiliation(s)
- Z Pirnik
- Laboratory of Functional Neuromorphology, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlarska Str. 3, 83306 Bratislava, Slovak Republic
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45
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Ghuman SPS, Morris R, Scherzer J, Routly JE, Mobasheri A, Smith RF, Dobson H. Neuronal Responses in the Brainstem and Hypothalamic Nuclei Following Insulin Treatment During the Late Follicular Phase in the Ewe. Reprod Domest Anim 2011; 46:121-9. [DOI: 10.1111/j.1439-0531.2010.01605.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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46
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Ghamari-Langroudi M, Srisai D, Cone RD. Multinodal regulation of the arcuate/paraventricular nucleus circuit by leptin. Proc Natl Acad Sci U S A 2011; 108:355-60. [PMID: 21169216 PMCID: PMC3017160 DOI: 10.1073/pnas.1016785108] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Melanocortin-4 receptor (MC4R) is critical for energy homeostasis, and the paraventricular nucleus of the hypothalamus (PVN) is a key site of MC4R action. Most studies suggest that leptin regulates PVN neurons indirectly, by binding to receptors in the arcuate nucleus or ventromedial hypothalamus and regulating release of products like α-melanocyte-stimulating hormone (α-MSH), neuropeptide Y (NPY), glutamate, and GABA from first-order neurons onto the MC4R PVN cells. Here, we investigate mechanisms underlying regulation of activity of these neurons under various metabolic states by using hypothalamic slices from a transgenic MC4R-GFP mouse to record directly from MC4R neurons. First, we show that in vivo leptin levels regulate the tonic firing rate of second-order MC4R PVN neurons, with fasting increasing firing frequency in a leptin-dependent manner. We also show that, although leptin inhibits these neurons directly at the postsynaptic membrane, α-MSH and NPY potently stimulate and inhibit the cells, respectively. Thus, in contrast with the conventional model of leptin action, the primary control of MC4R PVN neurons is unlikely to be mediated by leptin action on arcuate NPY/agouti-related protein and proopiomelanocortin neurons. We also show that the activity of MC4R PVN neurons is controlled by the constitutive activity of the MC4R and that expression of the receptor mRNA and α-MSH sensitivity are both stimulated by leptin. Thus, leptin acts multinodally on arcuate nucleus/PVN circuits to regulate energy homeostasis, with prominent mechanisms involving direct control of both membrane conductances and gene expression in the MC4R PVN neuron.
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Affiliation(s)
- Masoud Ghamari-Langroudi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615; and
| | - Dollada Srisai
- Department of Anatomy, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Roger D. Cone
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615; and
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Williams KW, Scott MM, Elmquist JK. Modulation of the central melanocortin system by leptin, insulin, and serotonin: co-ordinated actions in a dispersed neuronal network. Eur J Pharmacol 2011; 660:2-12. [PMID: 21211525 DOI: 10.1016/j.ejphar.2010.11.042] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/08/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Over the past century, prevalent models of energy and glucose homeostasis have been developed from a better understanding of the neural circuits underlying obesity and diabetes. From the early hypothalamic lesion reports to the more recent pharmacological and molecular/genetic studies, the hypothalamic melanocortin system has been shown to play a critical role in the regulation of metabolism. This review attempts to highlight contributions to our current understanding of how numerous neuromodulators (leptin, insulin, and serotonin) integrate with the central melanocortin system to coordinate alterations in energy and glucose balance.
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Affiliation(s)
- Kevin W Williams
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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48
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Abstract
Precise automatic control of food intake and energy expenditure maintains a steady weight and is fundamental to survival. The brainstem and hypothalamus are key areas within the brain that integrate peripheral signals from the gut and adipose tissue to control feeding behavior according to energy need. Gut hormones are released after a meal and signal to the brain to initiate meal termination and feelings of satiation. However, reward pathways are able to override this mechanism so that when palatable food is presented, food is consumed irrespective of energy requirements.
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Affiliation(s)
- Katherine A Simpson
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London, W12 0NN, UK
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Simpson KA, Martin NM, Bloom SR. Hypothalamic regulation of food intake and clinical therapeutic applications. ACTA ACUST UNITED AC 2010; 53:120-8. [PMID: 19466203 DOI: 10.1590/s0004-27302009000200002] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 02/15/2009] [Indexed: 02/07/2023]
Abstract
Current estimates suggest that over 1 billion people are overweight and over 300 million people are obese. Weight gain is due to an imbalance between energy expenditure and dietary intake. This review discusses the hypothalamic control of appetite and highlights key developments in research that have furthered our understanding of the complex pathways involved. Nuclei within the hypothalamus integrate peripheral signals such as adiposity and caloric intake to regulate important pathways within the central nervous system controlling food intake and energy expenditure. Firmly established pathways involve the orexigenic NPY/AgRP and the anorexigenic POMC/CART neurons in the arcuate nucleus (ARC) of the hypothalamus. These project from the ARC to other important hypothalamic nuclei, including the paraventricular, dorsomedial, ventromedial and lateral hypothalamic nuclei. In addition there are many projections to and from the brainstem, cortical areas and reward pathways, which modulate food intake.
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Segregation of acute leptin and insulin effects in distinct populations of arcuate proopiomelanocortin neurons. J Neurosci 2010; 30:2472-9. [PMID: 20164331 DOI: 10.1523/jneurosci.3118-09.2010] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Acute leptin administration results in a depolarization and concomitant increase in the firing rate of a subpopulation of arcuate proopiomelanocortin (POMC) cells. This rapid activation of POMC cells has been implicated as a cellular correlate of leptin effects on energy balance. In contrast to leptin, insulin inhibits the activity of some POMC neurons. Several studies have described a "cross talk" between leptin and insulin within the mediobasal hypothalamus via the intracellular enzyme, phosphoinositol-3-kinase (PI3K). Interestingly, both insulin and leptin regulate POMC cellular activity by activation of PI3K; however, it is unclear whether leptin and insulin effects are observed in similar or distinct populations of POMC cells. We therefore used dual label immunohistochemistry/in situ hybridization and whole-cell patch-clamp electrophysiology to map insulin and leptin responsive arcuate POMC neurons. Leptin-induced Fos activity within arcuate POMC neurons was localized separate from POMC neurons that express insulin receptor. Moreover, acute responses to leptin and insulin were largely segregated in distinct subpopulations of POMC cells. Collectively, these data suggest that cross talk between leptin and insulin occurs within a network of cells rather than within individual POMC neurons.
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