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Inyushkin AN, Mistryugov KA, Ledyaeva OV, Romanova ID, Isakova TS, Inyushkin AA. The Effects of Insulin on Spike Activity of the Suprachiasmatic Nucleus Neurones and Functional State of Afferent Inputs from the Arcuate Nucleus in Rats. J EVOL BIOCHEM PHYS+ 2023. [DOI: 10.1134/s0022093023010210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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2
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Tacad DKM, Tovar AP, Richardson CE, Horn WF, Keim NL, Krishnan GP, Krishnan S. Satiety Associated with Calorie Restriction and Time-Restricted Feeding: Central Neuroendocrine Integration. Adv Nutr 2022; 13:758-791. [PMID: 35134815 PMCID: PMC9156369 DOI: 10.1093/advances/nmac011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/08/2021] [Accepted: 02/02/2022] [Indexed: 02/06/2023] Open
Abstract
This review focuses on summarizing current knowledge on how time-restricted feeding (TRF) and continuous caloric restriction (CR) affect central neuroendocrine systems involved in regulating satiety. Several interconnected regions of the hypothalamus, brainstem, and cortical areas of the brain are involved in the regulation of satiety. Following CR and TRF, the increase in hunger and reduction in satiety signals of the melanocortin system [neuropeptide Y (NPY), proopiomelanocortin (POMC), and agouti-related peptide (AgRP)] appear similar between CR and TRF protocols, as do the dopaminergic responses in the mesocorticolimbic circuit. However, ghrelin and leptin signaling via the melanocortin system appears to improve energy balance signals and reduce hyperphagia following TRF, which has not been reported in CR. In addition to satiety systems, CR and TRF also influence circadian rhythms. CR influences the suprachiasmatic nucleus (SCN) or the primary circadian clock as seen by increased clock gene expression. In contrast, TRF appears to affect both the SCN and the peripheral clocks, as seen by phasic changes in the non-SCN (potentially the elusive food entrainable oscillator) and metabolic clocks. The peripheral clocks are influenced by the primary circadian clock but are also entrained by food timing, sleep timing, and other lifestyle parameters, which can supersede the metabolic processes that are regulated by the primary circadian clock. Taken together, TRF influences hunger/satiety, energy balance systems, and circadian rhythms, suggesting a role for adherence to CR in the long run if implemented using the TRF approach. However, these suggestions are based on only a few studies, and future investigations that use standardized protocols for the evaluation of the effect of these diet patterns (time, duration, meal composition, sufficiently powered) are necessary to verify these preliminary observations.
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Affiliation(s)
- Debra K M Tacad
- Obesity and Metabolism Research Unit, USDA–Western Human Nutrition Research Center, Davis, CA, USA,Department of Nutrition, University of California, Davis, Davis, CA, USA
| | - Ashley P Tovar
- Department of Nutrition, University of California, Davis, Davis, CA, USA
| | | | - William F Horn
- Obesity and Metabolism Research Unit, USDA–Western Human Nutrition Research Center, Davis, CA, USA
| | - Nancy L Keim
- Obesity and Metabolism Research Unit, USDA–Western Human Nutrition Research Center, Davis, CA, USA,Department of Nutrition, University of California, Davis, Davis, CA, USA
| | - Giri P Krishnan
- Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, USA
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3
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Finger AM, Dibner C, Kramer A. Coupled network of the circadian clocks: a driving force of rhythmic physiology. FEBS Lett 2020; 594:2734-2769. [PMID: 32750151 DOI: 10.1002/1873-3468.13898] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/06/2020] [Accepted: 07/21/2020] [Indexed: 12/15/2022]
Abstract
The circadian system is composed of coupled endogenous oscillators that allow living beings, including humans, to anticipate and adapt to daily changes in their environment. In mammals, circadian clocks form a hierarchically organized network with a 'master clock' located in the suprachiasmatic nucleus of the hypothalamus, which ensures entrainment of subsidiary oscillators to environmental cycles. Robust rhythmicity of body clocks is indispensable for temporally coordinating organ functions, and the disruption or misalignment of circadian rhythms caused for instance by modern lifestyle is strongly associated with various widespread diseases. This review aims to provide a comprehensive overview of our current knowledge about the molecular architecture and system-level organization of mammalian circadian oscillators. Furthermore, we discuss the regulatory roles of peripheral clocks for cell and organ physiology and their implication in the temporal coordination of metabolism in human health and disease. Finally, we summarize methods for assessing circadian rhythmicity in humans.
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Affiliation(s)
- Anna-Marie Finger
- Laboratory of Chronobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Charna Dibner
- Division of Endocrinology, Diabetes, Nutrition, and Patient Education, Department of Medicine, University Hospital of Geneva, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Diabetes Center, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Achim Kramer
- Laboratory of Chronobiology, Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
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4
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Pilorz V, Astiz M, Heinen KO, Rawashdeh O, Oster H. The Concept of Coupling in the Mammalian Circadian Clock Network. J Mol Biol 2020; 432:3618-3638. [PMID: 31926953 DOI: 10.1016/j.jmb.2019.12.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/22/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock network regulates daily rhythms in mammalian physiology and behavior to optimally adapt the organism to the 24-h day/night cycle. A central pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), coordinates subordinate cellular oscillators in the brain, as well as in peripheral organs to align with each other and external time. Stability and coordination of this vast network of cellular oscillators is achieved through different levels of coupling. Although coupling at the molecular level and across the SCN is well established and believed to define its function as pacemaker structure, the notion of coupling in other tissues and across the whole system is less well understood. In this review, we describe the different levels of coupling in the mammalian circadian clock system - from molecules to the whole organism. We highlight recent advances in gaining knowledge of the complex organization and function of circadian network regulation and its significance for the generation of stable but plastic intrinsic 24-h rhythms.
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Affiliation(s)
- Violetta Pilorz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Mariana Astiz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Keno Ole Heinen
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Oliver Rawashdeh
- The University of Queensland, School of Biomedical Sciences, Faculty of Medicine, St Lucia Qld, 4071, Australia
| | - Henrik Oster
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany.
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5
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Cedernaes J, Waldeck N, Bass J. Neurogenetic basis for circadian regulation of metabolism by the hypothalamus. Genes Dev 2019; 33:1136-1158. [PMID: 31481537 PMCID: PMC6719618 DOI: 10.1101/gad.328633.119] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Circadian rhythms are driven by a transcription-translation feedback loop that separates anabolic and catabolic processes across the Earth's 24-h light-dark cycle. Central pacemaker neurons that perceive light entrain a distributed clock network and are closely juxtaposed with hypothalamic neurons involved in regulation of sleep/wake and fast/feeding states. Gaps remain in identifying how pacemaker and extrapacemaker neurons communicate with energy-sensing neurons and the distinct role of circuit interactions versus transcriptionally driven cell-autonomous clocks in the timing of organismal bioenergetics. In this review, we discuss the reciprocal relationship through which the central clock drives appetitive behavior and metabolic homeostasis and the pathways through which nutrient state and sleep/wake behavior affect central clock function.
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Affiliation(s)
- Jonathan Cedernaes
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Nathan Waldeck
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Joseph Bass
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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6
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Evans MC, Anderson GM. Integration of Circadian and Metabolic Control of Reproductive Function. Endocrinology 2018; 159:3661-3673. [PMID: 30304391 DOI: 10.1210/en.2018-00691] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/03/2018] [Indexed: 12/11/2022]
Abstract
Optimal fertility in humans and animals relies on the availability of sufficient metabolic fuels, information about which is communicated to the brain via levels of the hormones leptin and insulin. The circadian clock system is also critical; this input is especially evident in the precise timing of the female-specific surge of GnRH and LH secretion that triggers ovulation the next day. Chronodisruption and metabolic imbalance can both impair reproductive activity, and these two disruptions exacerbate each other, such that they often occur simultaneously. Kisspeptin neurons located in the anteroventral periventricular nucleus of the hypothalamus are able to integrate both circadian and metabolic afferent inputs and use this information to modulate the timing and magnitude of the preovulatory GnRH/LH surge. In an environment in which exposure to high caloric diets and chronodisruptors such as artificial night lighting, shift work, and transmeridian travel have become the norm, the implications of these factors for couples struggling to conceive deserve closer attention and more public education.
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Affiliation(s)
- Maggie C Evans
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Greg M Anderson
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
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7
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Abstract
Most hormones display daily fluctuations of secretion during the 24-h cycle. This is also the case for adipokines, in particular the anorexigenic hormone, leptin. The temporal organization of the endocrine system is principally controlled by a network of circadian clocks. The circadian network comprises a master circadian clock, located in the suprachiasmatic nucleus of the hypothalamus, synchronized to the ambient light, and secondary circadian clocks found in various peripheral organs, such as the adipose tissues. Besides circadian clocks, other factors such as meals and metabolic status impact daily profiles of hormonal levels. In turn, the precise daily pattern of hormonal release provides temporal signaling information. This review will describe the reciprocal links between the circadian clocks and rhythmic secretion of leptin, and discuss the metabolic impact of circadian desynchronization and altered rhythmic leptin.
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Affiliation(s)
- Etienne Challet
- Circadian Clocks and Metabolism Team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de La Recherche Scientifique (CNRS), University of Strasbourg, France.
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8
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Isorna E, de Pedro N, Valenciano AI, Alonso-Gómez ÁL, Delgado MJ. Interplay between the endocrine and circadian systems in fishes. J Endocrinol 2017; 232:R141-R159. [PMID: 27999088 DOI: 10.1530/joe-16-0330] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/20/2016] [Indexed: 12/11/2022]
Abstract
The circadian system is responsible for the temporal organisation of physiological functions which, in part, involves daily cycles of hormonal activity. In this review, we analyse the interplay between the circadian and endocrine systems in fishes. We first describe the current model of fish circadian system organisation and the basis of the molecular clockwork that enables different tissues to act as internal pacemakers. This system consists of a net of central and peripherally located oscillators and can be synchronised by the light-darkness and feeding-fasting cycles. We then focus on two central neuroendocrine transducers (melatonin and orexin) and three peripheral hormones (leptin, ghrelin and cortisol), which are involved in the synchronisation of the circadian system in mammals and/or energy status signalling. We review the role of each of these as overt rhythms (i.e. outputs of the circadian system) and, for the first time, as key internal temporal messengers that act as inputs for other endogenous oscillators. Based on acute changes in clock gene expression, we describe the currently accepted model of endogenous oscillator entrainment by the light-darkness cycle and propose a new model for non-photic (endocrine) entrainment, highlighting the importance of the bidirectional cross-talking between the endocrine and circadian systems in fishes. The flexibility of the fish circadian system combined with the absence of a master clock makes these vertebrates a very attractive model for studying communication among oscillators to drive functionally coordinated outputs.
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Affiliation(s)
- Esther Isorna
- Departamento de Fisiología (Fisiología Animal II)Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Nuria de Pedro
- Departamento de Fisiología (Fisiología Animal II)Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Ana I Valenciano
- Departamento de Fisiología (Fisiología Animal II)Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Ángel L Alonso-Gómez
- Departamento de Fisiología (Fisiología Animal II)Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - María J Delgado
- Departamento de Fisiología (Fisiología Animal II)Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
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Differences in Photic Entrainment of Circadian Locomotor Activity Between Lean and Obese Volcano Mice ( Neotomodon alstoni). J Circadian Rhythms 2017; 15:1. [PMID: 30210555 PMCID: PMC5356206 DOI: 10.5334/jcr.145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Obesity is a growing problem worldwide with a clear impact on health status. It is also a condition that negatively affects circadian rhythms. When the mouse Neotomodon alstoni is fed a regular rodent chow, some individuals develop obesity, representing an opportunity to compare the effects of spontaneous obesity upon the circadian organization in this species with that observed in other rodents with induced obesity. We report differences in the free running circadian locomotor activity rhythm and in the effects of light pulses between lean and obese mice. Also, the photo-induced expression of the c-Fos protein and vasoactive intestinal peptide (VIP) in the suprachiasmatic nucleus (SCN) were examined at circadian time (CT) 14 and 22. We show that obese mice have a larger dispersion of the period of circadian locomotor rhythm in constant darkness. Photic induced phase shifts are nearly 50% shorter at CT 14, and 50% larger at CT 22 than in lean mice. The photoinduction of VIP in the SCN at CT 22 was larger in obese mice, which may be related to the differences observed in photic phase shifting. Our work indicates that the obesity in Neotomodon has effects on the neural mechanisms that regulate the circadian system.
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10
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Abstract
The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in feeding behavior and increased weight gain. Thus, shift work is associated with increased risk for obesity, diabetes and cardio-vascular diseases as a result of unusual eating time and disruption of circadian rhythm.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey.
- , Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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11
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Derous D, Mitchell SE, Green CL, Chen L, Han JJ, Wang Y, Promislow DE, Lusseau D, Speakman JR, Douglas A. The effects of graded levels of calorie restriction: VI. Impact of short-term graded calorie restriction on transcriptomic responses of the hypothalamic hunger and circadian signaling pathways. Aging (Albany NY) 2016; 8:642-63. [PMID: 26945906 PMCID: PMC4925820 DOI: 10.18632/aging.100895] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/20/2016] [Indexed: 01/03/2023]
Abstract
Food intake and circadian rhythms are regulated by hypothalamic neuropeptides and circulating hormones, which could mediate the anti-ageing effect of calorie restriction (CR). We tested whether these two signaling pathways mediate CR by quantifying hypothalamic transcripts of male C57BL/6 mice exposed to graded levels of CR (10 % to 40 %) for 3 months. We found that the graded CR manipulation resulted in upregulation of core circadian rhythm genes, which correlated negatively with circulating levels of leptin, insulin-like growth factor 1 (IGF-1), insulin, and tumor necrosis factor alpha (TNF-α). In addition, key components in the hunger signaling pathway were expressed in a manner reflecting elevated hunger at greater levels of restriction, and which also correlated negatively with circulating levels of insulin, TNF-α, leptin and IGF-1. Lastly, phenotypes, such as food anticipatory activity and body temperature, were associated with expression levels of both hunger genes and core clock genes. Our results suggest modulation of the hunger and circadian signaling pathways in response to altered levels of circulating hormones, that are themselves downstream of morphological changes resulting from CR treatment, may be important elements in the response to CR, driving some of the key phenotypic outcomes.
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Affiliation(s)
- Davina Derous
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, Aberdeen, Scotland, AB24 3RL, UK
| | - Sharon E. Mitchell
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
| | - Cara L. Green
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
| | - Luonan Chen
- Key laboratory of Systems Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jing‐Dong J. Han
- Chinese Academy of Sciences Key Laboratory of Computational Biology, Chinese Academy of Sciences‐Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yingchun Wang
- State Key laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, 100101, China
| | - Daniel E.L. Promislow
- Department of Pathology and Department of Biology, University of Washington at Seattle, Seattle, WA 98195, USA
| | - David Lusseau
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
| | - John R. Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
- State Key laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, 100101, China
| | - Alex Douglas
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, AB24 2TZ, UK
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, Aberdeen, Scotland, AB24 3RL, UK
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12
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Role of Leptin and Orexin-A Within the Suprachiasmatic Nucleus on Anxiety-Like Behaviors in Hamsters. Mol Neurobiol 2016; 54:2674-2684. [DOI: 10.1007/s12035-016-9847-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/09/2016] [Indexed: 01/09/2023]
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13
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Chowen JA, Argente-Arizón P, Freire-Regatillo A, Frago LM, Horvath TL, Argente J. The role of astrocytes in the hypothalamic response and adaptation to metabolic signals. Prog Neurobiol 2016; 144:68-87. [PMID: 27000556 DOI: 10.1016/j.pneurobio.2016.03.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 02/09/2016] [Accepted: 03/04/2016] [Indexed: 12/19/2022]
Abstract
The hypothalamus is crucial in the regulation of homeostatic functions in mammals, with the disruption of hypothalamic circuits contributing to chronic conditions such as obesity, diabetes mellitus, hypertension, and infertility. Metabolic signals and hormonal inputs drive functional and morphological changes in the hypothalamus in attempt to maintain metabolic homeostasis. However, the dramatic increase in the incidence of obesity and its secondary complications, such as type 2 diabetes, have evidenced the need to better understand how this system functions and how it can go awry. Growing evidence points to a critical role of astrocytes in orchestrating the hypothalamic response to metabolic cues by participating in processes of synaptic transmission, synaptic plasticity and nutrient sensing. These glial cells express receptors for important metabolic signals, such as the anorexigenic hormone leptin, and determine the type and quantity of nutrients reaching their neighboring neurons. Understanding the mechanisms by which astrocytes participate in hypothalamic adaptations to changes in dietary and metabolic signals is fundamental for understanding the neuroendocrine control of metabolism and key in the search for adequate treatments of metabolic diseases.
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Affiliation(s)
- Julie A Chowen
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, CIBER de Obesidad Fisiopatología de la Obesidad y Nutrición (CIBEROBN). Instituto de Salud Carlos III, Madrid, Spain.
| | - Pilar Argente-Arizón
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, CIBER de Obesidad Fisiopatología de la Obesidad y Nutrición (CIBEROBN). Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Alejandra Freire-Regatillo
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, CIBER de Obesidad Fisiopatología de la Obesidad y Nutrición (CIBEROBN). Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura M Frago
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, CIBER de Obesidad Fisiopatología de la Obesidad y Nutrición (CIBEROBN). Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jesús Argente
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, CIBER de Obesidad Fisiopatología de la Obesidad y Nutrición (CIBEROBN). Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
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14
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Abstract
Daily variations of metabolism, physiology and behaviour are controlled by a network of coupled circadian clocks, comprising a master clock in the suprachiasmatic nuclei of the hypothalamus and a multitude of secondary clocks in the brain and peripheral organs. Light cues synchronize the master clock that conveys temporal cues to other body clocks via neuronal and hormonal signals. Feeding at unusual times can reset the phase of most peripheral clocks. While the neuroendocrine aspect of circadian regulation has been underappreciated, this review aims at showing that the role of hormonal rhythms as internal time-givers is the rule rather than the exception. Adrenal glucocorticoids, pineal melatonin and adipocyte-derived leptin participate in internal synchronization (coupling) within the multi-oscillatory network. Furthermore, pancreatic insulin is involved in food synchronization of peripheral clocks, while stomach ghrelin provides temporal signals modulating behavioural anticipation of mealtime. Circadian desynchronization induced by shift work or chronic jet lag has harmful effects on metabolic regulation, thus favouring diabetes and obesity. Circadian deregulation of hormonal rhythms may participate in internal desynchronization and associated increase in metabolic risks. Conversely, adequate timing of endocrine therapies can promote phase-adjustment of the master clock (e.g. via melatonin agonists) and peripheral clocks (e.g. via glucocorticoid agonists).
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Affiliation(s)
- E Challet
- Institute of Cellular and Integrative Neurosciences, UPR3212 Centre National de la Recherche Scientifique, University of Strasbourg, Strasbourg, France
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15
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Grosbellet E, Gourmelen S, Pévet P, Criscuolo F, Challet E. Leptin normalizes photic synchronization in male ob/ob mice, via indirect effects on the suprachiasmatic nucleus. Endocrinology 2015; 156:1080-90. [PMID: 25521581 DOI: 10.1210/en.2014-1570] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mounting evidence indicates a strong link between metabolic diseases and circadian dysfunctions. The metabolic hormone leptin, substantially increased in dietary obesity, displays chronobiotic properties. Here we investigated whether leptin is involved in the alteration of timing associated with obesity, via direct or indirect effects on the suprachiasmatic nucleus (SCN), the site of the master clock. Photic synchronization was studied in obese ob/ob mice (deficient in leptin), either injected or not with high doses of recombinant murine leptin (5 mg/kg). This was performed first at a behavioral level, by shifting the light-dark cycle and inducing phase shifts by 30-minute light pulses and then at molecular levels (c-FOS and P-ERK1/2). Moreover, to characterize the targets mediating the chronomodulatory effects of leptin, we studied the induction of phosphorylated signal transducer and activator of transcription 3 (P-STAT3) in the SCN and in different structures projecting to the SCN, including the medial hypothalamus. Ob/ob mice showed altered photic synchronization, including augmented light-induced phase delays. Acute leptin treatment normalized the photic responses of the SCN at both the behavioral and molecular levels (decrease of light-induced c-FOS). Leptin-induced P-STAT3 was modulated by light in the arcuate nucleus and both the ventromedial and dorsomedial hypothalamic nuclei, whereas its expression was independent of the presence of leptin in the SCN. These results suggest an indirect action of leptin on the SCN, possibly mediated by the medial hypothalamus. Taken together, these results highlight a central role of leptin in the relationship between metabolic disturbances and circadian disruptions.
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Affiliation(s)
- Edith Grosbellet
- Regulation of Circadian Clocks Team (E.G., S.G., P.P., E.C.), Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique UPR3212, and Evolutionary Ecophysiology Team (E.G., F.C.), Department of Ecology, Physiology, and Ethology, Hubert Curien Pluridisciplinary Institute, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7178, University of Strasbourg, 67000 Strasbourg, France
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16
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Tinoco AB, Nisembaum LG, de Pedro N, Delgado MJ, Isorna E. Leptin expression is rhythmic in brain and liver of goldfish (Carassius auratus). Role of feeding time. Gen Comp Endocrinol 2014; 204:239-47. [PMID: 24932715 DOI: 10.1016/j.ygcen.2014.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/28/2014] [Accepted: 06/05/2014] [Indexed: 12/01/2022]
Abstract
Daily rhythms of feeding regulators are currently arousing research interest due to the relevance of the temporal harmony of endocrine regulators for growth and welfare in vertebrates. However, it is unknown the leptin circadian pattern in fish. The aim of this study is to investigate if leptin (gLep-aI and gLep-aII) expression is rhythmic in goldfish (Carassius auratus) liver and brain, and if such rhythms are driven by feeding time through a food entrainable oscillator. Fish maintained under 12-h light:12-h dark photoperiod and a scheduled feeding time showed 24-h locomotor activity and glycaemia rhythms. Moreover, hepatic gLep-aI and brain gLep-aI and gLep-aII expression were rhythmic with different daily profiles, showing a postprandial increase of leptin expression in the liver but not in the brain. Under constant light and different feeding regimes (scheduled fed at 10:00, 22:00 or randomly fed), feeding time synchronized daily rhythms in locomotor activity, glycaemia and clock gene expression (gPer1a, gPer3 and gCry3), but the rhythmic expression of hepatic gLep-aI and brain gLep-aII only remained in fed fish at 10:00. In summary, daily rhythms of leptin expression in goldfish are differently regulated at central and peripheral level, and they are not directly driven by clock genes. The role of food entrained oscillators on leptin expression rhythms in fish remains to be demonstrated.
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Affiliation(s)
- Ana B Tinoco
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Laura G Nisembaum
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Nuria de Pedro
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - María J Delgado
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Esther Isorna
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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17
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Circadian Clocks and Inflammation: Reciprocal Regulation and Shared Mediators. Arch Immunol Ther Exp (Warsz) 2014; 62:303-18. [DOI: 10.1007/s00005-014-0286-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 01/22/2014] [Indexed: 02/06/2023]
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18
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Tokizawa K, Onoue Y, Uchida, Y, Nagashima K. Ghrelin Induces Time-Dependent Modulation of Thermoregulation in the Cold. Chronobiol Int 2012; 29:736-46. [DOI: 10.3109/07420528.2012.678452] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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19
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Carmona-Alcocer V, Fuentes-Granados C, Carmona-Castro A, Aguilar-González I, Cárdenas-Vázquez R, Miranda-Anaya M. Obesity alters circadian behavior and metabolism in sex dependent manner in the volcano mouse Neotomodon alstoni. Physiol Behav 2011; 105:727-33. [PMID: 22001494 DOI: 10.1016/j.physbeh.2011.09.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/29/2011] [Accepted: 09/29/2011] [Indexed: 01/12/2023]
Abstract
The aim of the present study is to evaluate whether circadian locomotor activity, and the daily profile of plasma parameters related to metabolic syndrome (nutrients: glucose and triacylglycerides, and hormones: insulin and leptin), differ between male and female Neotomodon alstoni mice, both lean and obese. Young adult animals were captured in the field and kept at the laboratory animal facility. After 6 to 7 months feeding the animals ad libitum with a regular diet for laboratory rodents, 50-60% of mice became obese. Comparisons between sexes indicated that lean females were more active than males; however obese females reduced their nocturnal activity either in LD or DD, and advanced the phase of their activity-onset with respect to lights off. No differences in food intake between lean and obese mice, either during the day or night, were observed. Daily profiles of metabolic syndrome-related plasma parameters showed differences between sexes, and obesity was associated with increased values, especially leptin (500% in females and 273% in males) and insulin (150% in both females and males), as compared with lean mice. Our results indicate that lean mice display behavioral and endocrine differences between sexes, and obesity affects the parameters tested in a sex-dependent manner. The aforementioned leads us to propose N. alstoni, studied in captivity, could be an interesting model for the study of sex differences in the effects of obesity.
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Affiliation(s)
- Vania Carmona-Alcocer
- Departamento de Biología Celular, Facultad de Ciencias, UNAM 04510, México D.F., México
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20
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Antunes LDC, Jornada MND, Ramalho L, Hidalgo MPL. Correlation of shift work and waist circumference, body mass index, chronotype and depressive symptoms. ACTA ACUST UNITED AC 2011; 54:652-6. [PMID: 21085771 DOI: 10.1590/s0004-27302010000700010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 09/09/2010] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Correlate shift work with body mass index (BMI), waist circumference, chronotype and depressive symptoms. SUBJECTS AND METHODS This study comprising 14 shift workers and 13 day workers. Subjects were workers from the health area aged 25 to 60 years. Minor psychiatric disorders were accessed by Self Report Questionnaire (SRQ-20) and depressive symptoms by Beck Depression Inventory (BDI). Chronotype was accessed using Morningness-Eveningness Questionnaire (MEQ). Anthropometric measures were taken. RESULTS Shift workers presented higher BMI (P = 0.03) and waist circumference (P = 0.004) than day workers. Years on shift work were significantly correlated to waist circumference (r = 0.43; P = 0.03) and age (r = 0.47; P = 0.02). Shift work was not correlated with depressive symptoms and chronotype. CONCLUSION These results may suggest a role played by shift work on the development and/or the early clinic manifestations of metabolic disturbances, becoming a risk factor to metabolic syndrome.
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21
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Long-lived mice exhibit 24h locomotor circadian rhythms at young and old age. Exp Gerontol 2011; 46:606-9. [DOI: 10.1016/j.exger.2011.02.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 02/11/2011] [Accepted: 02/23/2011] [Indexed: 11/19/2022]
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22
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Ren P, Zhang H, Qiu F, Liu YQ, Gu H, O'Dowd DK, Zhou QY, Hu WP. Prokineticin 2 regulates the electrical activity of rat suprachiasmatic nuclei neurons. PLoS One 2011; 6:e20263. [PMID: 21687716 PMCID: PMC3110640 DOI: 10.1371/journal.pone.0020263] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 04/21/2011] [Indexed: 12/11/2022] Open
Abstract
Neuropeptide signaling plays roles in coordinating cellular activities and maintaining robust oscillations within the mammalian suprachiasmatic nucleus (SCN). Prokineticin2 (PK2) is a signaling molecule from the SCN and involves in the generation of circadian locomotor activity. Prokineticin receptor 2 (PKR2), a receptor for PK2, has been shown to be expressed in the SCN. However, very little is known about the cellular action of PK2 within the SCN. In the present study, we investigated the effect of PK2 on spontaneous firing and miniature inhibitory postsynaptic currents (mIPSCs) using whole cell patch-clamp recording in the SCN slices. PK2 dose-dependently increased spontaneous firing rates in most neurons from the dorsal SCN. PK2 acted postsynaptically to reduce γ-aminobutyric acid (GABA)-ergic function within the SCN, and PK2 reduced the amplitude but not frequency of mIPSCs. Furthermore, PK2 also suppressed exogenous GABA-induced currents. And the inhibitory effect of PK2 required PKC activation in the postsynaptic cells. Our data suggest that PK2 could alter cellular activities within the SCN and may influence behavioral and physiological rhythms.
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Affiliation(s)
- Ping Ren
- Department of Pharmacology, Xianning College, Xianning, Hubei, People's Republic of China
| | - Huiping Zhang
- Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Fang Qiu
- Department of Pharmacology, Xianning College, Xianning, Hubei, People's Republic of China
| | - Yu-Qiang Liu
- Department of Pharmacology, Xianning College, Xianning, Hubei, People's Republic of China
| | - Huaiyu Gu
- Departments of Anatomy and Neurobiology, Developmental and Cell Biology, University of California Irvine, Irvine, California, United States of America
| | - Diane K. O'Dowd
- Departments of Anatomy and Neurobiology, Developmental and Cell Biology, University of California Irvine, Irvine, California, United States of America
| | - Qun-Yong Zhou
- Department of Pharmacology, University of California Irvine, Irvine, California, United States of America
| | - Wang-Ping Hu
- Department of Pharmacology, Xianning College, Xianning, Hubei, People's Republic of China
- * E-mail:
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Ando H, Kumazaki M, Motosugi Y, Ushijima K, Maekawa T, Ishikawa E, Fujimura A. Impairment of peripheral circadian clocks precedes metabolic abnormalities in ob/ob mice. Endocrinology 2011; 152:1347-54. [PMID: 21285316 DOI: 10.1210/en.2010-1068] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent studies have demonstrated relationships between the dysfunction of circadian clocks and the development of metabolic abnormalities, but the chicken-and-egg question remains unresolved. To address this issue, we investigated the cause-effect relationship in obese, diabetic ob/ob mice. Compared with control C57BL/6J mice, the daily mRNA expression profiles of the clock and clock-controlled genes Clock, Bmal1, Cry1, Per1, Per2, and Dbp were substantially dampened in the liver and adipose tissue, but not the hypothalamic suprachiasmatic nucleus, of 10-wk-old ob/ob mice. Four-week feeding of a low-calorie diet and administration of leptin over a 7-d period attenuated, to a significant and comparable extent, the observed metabolic abnormalities (obesity, hyperglycemia, hyperinsulinemia, and hypercholesterolemia) in the ob/ob mice. However, only leptin treatment improved the impaired peripheral clocks. In addition, clock function, assessed by measuring levels of Per1, Per2, and Dbp mRNA at around peak times, was also reduced in the peripheral tissues of 3-wk-old ob/ob mice without any overt metabolic abnormalities. Collectively these results indicate that the impairment of peripheral clocks in ob/ob mice does not result from metabolic abnormalities but may instead be at least partially caused by leptin deficiency itself. Further studies are needed to clarify how leptin deficiency affects peripheral clocks.
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Affiliation(s)
- Hitoshi Ando
- Division of Clinical Pharmacology, Department of Pharmacology, School of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
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24
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Mendoza J, Lopez-Lopez C, Revel FG, Jeanneau K, Delerue F, Prinssen E, Challet E, Moreau JL, Grundschober C. Dimorphic effects of leptin on the circadian and hypocretinergic systems of mice. J Neuroendocrinol 2011; 23:28-38. [PMID: 20874776 DOI: 10.1111/j.1365-2826.2010.02072.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hormone leptin controls food intake and body weight through its receptor in the hypothalamus, and may modulate physiological functions such as reproduction, sleep or circadian timing. In the present study, the effects of leptin on the resetting of the circadian clock, the hypothalamic suprachiasmatic nucleus (SCN) and on the activity of the hypocretinergic system were examined in vivo, with comparative analysis between male and female mice. A single leptin injection (5 mg/kg) at both the onset and offset of the activity period did not alter locomotion of mice housed under a 12 : 12 h light/dark cycle and did not shift the circadian behavioral rhythm of mice housed in constant darkness. By contrast, leptin potentiated the phase-shifting effect of a 30-min light-pulse on behavioural rhythms during the late subjective night, although only in females. This was accompanied by a higher induction of the clock genes Per1 and Per2 in the SCN. A 2-week chronic exposure to a physiological dose of leptin (100 μg/kg per day) decreased locomotor activity, expression of hypocretin receptor 1 and 2, as well as the number of hypocretin-immunoreactive neurones only in female mice, whereas the number of c-fos-positive hypocretinergic neurones was reduced in both genders. These results highlight a dimorphic effect of leptin on the hypocretinergic system and on the response of the circadian clock to light. Leptin may thus modulate the sleep/wake cycle and circadian system beside its well-established action on food intake and regulation of body weight.
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Affiliation(s)
- J Mendoza
- Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique, UPR3212 University of Strasbourg, Strasbourg, France.
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25
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Abstract
Reading the spike coding of hypothalamic neurones presents a considerable challenge because they exhibit highly irregular firing patterns. Electrophysiologists working in the motor and sensory systems, in which neurones fire more regularly, have devised satisfactory methods to describe the firing of cells, although the statistical assumptions that underlie the methods do not apply to hypothalamic neurones. Measurement of neural activity is nevertheless vital to characterise the activity of neuroendocrine cells. It has thus become necessary to develop methods suitable for the analysis of the highly irregular spike discharge patterns of both spontaneous and stimulus-evoked firing of hypothalamic neurones. We review techniques used to meet this challenge and demonstrate their considerable capacity to address important physiological questions. We also introduce a novel approach for valid statistical estimation of the information conveyed by the response of a single neurone to a periodic stimulus. The approach demonstrated significant diurnal rhythms of synaptic connectivity between hypothalamic nuclei.
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Affiliation(s)
- G S Bhumbra
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK.
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26
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Demas GE. In vivo but not in vitro leptin enhances lymphocyte proliferation in Siberian hamsters (Phodopus sungorus). Gen Comp Endocrinol 2010; 166:314-9. [PMID: 19896948 DOI: 10.1016/j.ygcen.2009.10.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/06/2009] [Accepted: 10/28/2009] [Indexed: 11/16/2022]
Abstract
Mounting an immune response requires a relatively substantial investment of energy and marked reductions in energy availability can suppress immune function and presumably increase disease susceptibility. We have previously demonstrated that a moderate reduction in energy stores by partial surgical lipectomy impairs humoral immunity of Siberian hamsters (Phodopus sungorus) and is mediated, in part, by changes in the adipose tissue hormone leptin. The goals of the present study were to assess the role of leptin in cell-mediated immunity and to determine if the potential effects of leptin on immunity are via the direct actions of this hormone on lymphocytes, or indirect, via the sympathetic nervous system (SNS). In Experiment 1, hamsters received osmotic minipumps containing either murine leptin (0.5 microl/h) or vehicle alone for 10 days and splenocyte proliferation in response to the T-cell mitogen Concanavalin A (Con A) was determined. In Experiment 2, Con A-induced splenocyte proliferation was tested in the presence or absence of leptin in vitro. In Experiment 3, exogenous leptin was administered to intact or sympathetically denervated hamsters. Hamsters treated with in vivo leptin displayed increased splenocyte proliferation compared with control hamsters receiving vehicle. In contrast, in vitro leptin had no effect on splenocyte proliferation. Sympathetic denervation attenuated, but did not block, leptin-induced increases in immunity. Taken together, these results are consistent with the idea that leptin can enhance cell-mediated immunity; the SNS appears to contribute, least in part, to leptin-induced increases in immunity. Importantly, these findings confirm previous studies that leptin serves as an important endocrine link between energy balance and immunity.
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Affiliation(s)
- Gregory E Demas
- Department of Biology, Program in Neuroscience and the Center for the Integrative Study of Animal Behavior, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA.
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Abstract
The present review has the objective of summarising chronobiological aspects of shift work and obesity. There was a systematic search in PubMed databases, using the following descriptors: shift work; obesity; biological clock. Shift work is extremely frequent in several services and industries, in order to systematise the needs for flexibility of the workforce, necessary to optimise productivity and business competitiveness. In developing countries, this population represents a considerable contingent workforce. Recently, studies showed that overweight and obesity are more prevalent in shift workers than day workers. In addition, the literature shows that shift workers seem to gain weight more often than those workers submitted to a usual work day. In conclusion, there is considerable epidemiological evidence that shift work is associated with increased risk for obesity, diabetes and CVD, perhaps as a result of physiological maladaptation to chronically sleeping and eating at abnormal circadian times. The impact of shift work on metabolism supports a possible pathway to the development of obesity and its co-morbities. The present review demonstrated the adverse cardiometabolic implications of circadian misalignment, as occurs chronically with shift workers.
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