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Cassie N, Anderson R, Wilson D, Mercer JG, Barrett P. Fat, carbohydrate and protein by oral gavage in the rat can be equally effective for satiation. Physiol Behav 2019; 207:41-47. [PMID: 31034840 DOI: 10.1016/j.physbeh.2019.04.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/25/2019] [Accepted: 04/25/2019] [Indexed: 01/28/2023]
Abstract
This study aimed to determine the relative efficacy of the macronutrients, protein, fat and carbohydrate to induce satiation and satiety in rats in relation to macronutrient activation of neurons in the nucleus of the solitary tract (NTS). Male Sprague Dawley rats were schedule-fed twice a day for 2 h, receiving 100% of daily ad-libitum energy intake. On test day 1, 30 min before the first scheduled meal of the day, rats were gavaged with an 8 kcal isocaloric, isovolumetric solution of a glucose, lipid or peptone macronutrient solution or a non-caloric saline solution. To assess satiation, thirty minutes later rats were given access to food for 2 h and food intake determined. A second 2 h food access period 3 h later was used for assessment of satiety. On the second test day, rats were gavaged as before and killed 90 min after food presentation. Blood was collected for measurement of circulating metabolic markers. Brains were removed for analysis of c-Fos expression by in situ hybridization in the NTS. Rats which received saline consumed a similar amount of food compared to pre-gavage intakes. However, rats gavaged with a caloric macronutrient solution all reduced food intake by 18-20 kcal. Interestingly, the reduction in caloric intake was greater than the caloric value of the macronutrient solution gavaged and was sustained following the second scheduled meal. Quantification by in situ hybridization of c-Fos mRNA expression in the NTS 90 min post-gavage, showed a significant increase with each macronutrient, but was 24-29% higher with a lipid or peptone gavage compared to a glucose gavage. In conclusion, when delivered directly to the stomach, all macronutrients can be equally effective in inducing satiation with significant neuronal activation in the NTS of the hindbrain.
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Affiliation(s)
- Nikki Cassie
- Rowett Institute, University of Aberdeen, Foresterhill Campus, Aberdeen AB25 2ZB, UK
| | - Richard Anderson
- Rowett Institute, University of Aberdeen, Foresterhill Campus, Aberdeen AB25 2ZB, UK
| | - Dana Wilson
- Rowett Institute, University of Aberdeen, Foresterhill Campus, Aberdeen AB25 2ZB, UK
| | - Julian G Mercer
- Rowett Institute, University of Aberdeen, Foresterhill Campus, Aberdeen AB25 2ZB, UK
| | - Perry Barrett
- Rowett Institute, University of Aberdeen, Foresterhill Campus, Aberdeen AB25 2ZB, UK.
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2
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Wu CS, Bongmba OYN, Lee JH, Tuchaai E, Zhou Y, Li DP, Xue B, Chen Z, Sun Y. Ghrelin receptor in agouti-related peptide neurones regulates metabolic adaptation to calorie restriction. J Neuroendocrinol 2019; 31:e12763. [PMID: 31251830 PMCID: PMC7233797 DOI: 10.1111/jne.12763] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/16/2022]
Abstract
Ghrelin is a gut hormone that signals to the hypothalamus to stimulate growth hormone release, increase food intake and promote fat deposition. The ghrelin receptor, also known as growth hormone secretagogue receptor (GHS-R), is highly expressed in the brain, with the highest expression in agouti-related peptide (AgRP) neurones in the hypothalamus. Compelling evidence indicates that ghrelin serves as a survival hormone with respect to maintaining blood glucose and body weight during nutritional deficiencies. Recent studies have demonstrated that AgRP neurones are involved in metabolic and behavioural adaptation to an energy deficit to improve survival. In the present study, we used a neuronal subtype-specific GHS-R knockout mouse (AgRP-Cre;Ghsrf/f ) to investigate the role of GHS-R in hypothalamic AgRP neurones in metabolic and behavioural adaptation to hypocaloric restricted feeding. We subjected the mice to a restricted feeding regimen of 40% mild calorie restriction (CR), with one-quarter of food allotment given in the beginning of the light cycle and three-quarters given at the beginning of the dark cycle, to mimic normal mouse intake pattern. The CR-fed AgRP-Cre;Ghsrf/f mice exhibited reductions in body weight, fat mass and blood glucose. Metabolic profiling of these CR-fed AgRP-Cre;Ghsrf/f mice showed a trend toward reduced basal metabolic rate, significantly reduced core body temperature and a decreased expression of thermogenic genes in brown adipose tissue. This suggests a metabolic reset to a lower threshold. Significantly increased physical activity, a trend toward increased food anticipatory behaviour and altered fuel preferences were also observed in these mice. In addition, these CR-fed AgRP-Cre;Ghsrf/f mice exhibited a decreased counter-regulatory response, showing impaired hepatic glucose production. Lastly, hypothalamic gene expression in AgRP-Cre;Ghsrf/f mice revealed increased AgRP expression and a decreased expression of genes in β-oxidation pathways. In summary, our data suggest that GHS-R in AgRP neurones is a key component of the neurocircuitry involved in metabolic adaptation to calorie restriction.
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Affiliation(s)
- Chia-Shan Wu
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Odelia Y. N. Bongmba
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jong Han Lee
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- College of Pharmacy, Gachon University, Incheon, 21936, Korea
| | - Ellie Tuchaai
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - De-Pei Li
- Center for precision medicine, School of Medicine, University of Missouri. Columbia, MO 65212, USA
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Zheng Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, TX 77030, USA
| | - Yuxiang Sun
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- To whom correspondence should be addressed: Dr. Yuxiang Sun, mailing address: Department of Nutrition and Food Science, Texas A&M University, 214C Cater-Mattil, 2253 TAMU, College Station, TX 77843. Phone: 979-862-9143;
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3
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Fernandez G, Cabral A, Andreoli MF, Labarthe A, M'Kadmi C, Ramos JG, Marie J, Fehrentz JA, Epelbaum J, Tolle V, Perello M. Evidence Supporting a Role for Constitutive Ghrelin Receptor Signaling in Fasting-Induced Hyperphagia in Male Mice. Endocrinology 2018; 159:1021-1034. [PMID: 29300858 DOI: 10.1210/en.2017-03101] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/21/2017] [Indexed: 01/22/2023]
Abstract
Ghrelin is a potent orexigenic peptide hormone that acts through the growth hormone secretagogue receptor (GHSR), a G protein-coupled receptor highly expressed in the hypothalamus. In vitro studies have shown that GHSR displays a high constitutive activity, whose physiological relevance is uncertain. As GHSR gene expression in the hypothalamus is known to increase in fasting conditions, we tested the hypothesis that constitutive GHSR activity at the hypothalamic level drives the fasting-induced hyperphagia. We found that refed wild-type (WT) mice displayed a robust hyperphagia that continued for 5 days after refeeding and changed their food intake daily pattern. Fasted WT mice showed an increase in plasma ghrelin levels, as well as in GHSR expression levels and ghrelin binding sites in the hypothalamic arcuate nucleus. When fasting-refeeding responses were evaluated in ghrelin- or GHSR-deficient mice, only the latter displayed an ∼15% smaller hyperphagia, compared with WT mice. Finally, fasting-induced hyperphagia of WT mice was significantly smaller in mice centrally treated with the GHSR inverse agonist K-(D-1-Nal)-FwLL-NH2, compared with mice treated with vehicle, whereas it was unaffected in mice centrally treated with the GHSR antagonists D-Lys3-growth hormone-releasing peptide 6 or JMV2959. Taken together, genetic models and pharmacological results support the notion that constitutive GHSR activity modulates the magnitude of the compensatory hyperphagia triggered by fasting. Thus, the hypothalamic GHSR signaling system could affect the set point of daily food intake, independently of plasma ghrelin levels, in situations of negative energy balance.
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Affiliation(s)
- Gimena Fernandez
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology (Argentine Research Council, Scientific Research Commission of the Province of Buenos Aires and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - Agustina Cabral
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology (Argentine Research Council, Scientific Research Commission of the Province of Buenos Aires and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - María F Andreoli
- School of Biochemistry and Biological Sciences, National University of Litoral and Institute of Environmental Health, Santa Fe, Argentina
| | - Alexandra Labarthe
- Centre de Psychiatrie et Neurosciences Unité Mixte de Recherche Scientifique_S894 INSERM Université Paris Descartes, Sorbonne Paris-Cité, Paris, France
| | - Céline M'Kadmi
- Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche Scientifique 5247 Centre National de la Recherche Scientifique-Université Montpellier-École Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Montpellier, France
| | - Jorge G Ramos
- School of Biochemistry and Biological Sciences, National University of Litoral and Institute of Environmental Health, Santa Fe, Argentina
| | - Jacky Marie
- Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche Scientifique 5247 Centre National de la Recherche Scientifique-Université Montpellier-École Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Montpellier, France
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche Scientifique 5247 Centre National de la Recherche Scientifique-Université Montpellier-École Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Montpellier, France
| | - Jacques Epelbaum
- Centre de Psychiatrie et Neurosciences Unité Mixte de Recherche Scientifique_S894 INSERM Université Paris Descartes, Sorbonne Paris-Cité, Paris, France
- Mécanismes Adaptatifs et Evolution, Unité Mixte de Recherche Scientifique 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France, Brunoy, France
| | - Virginie Tolle
- Centre de Psychiatrie et Neurosciences Unité Mixte de Recherche Scientifique_S894 INSERM Université Paris Descartes, Sorbonne Paris-Cité, Paris, France
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology (Argentine Research Council, Scientific Research Commission of the Province of Buenos Aires and National University of La Plata), La Plata, Buenos Aires, Argentina
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4
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Rogers NH, Walsh H, Alvarez-Garcia O, Park S, Gaylinn B, Thorner MO, Smith RG. Metabolic Benefit of Chronic Caloric Restriction and Activation of Hypothalamic AGRP/NPY Neurons in Male Mice Is Independent of Ghrelin. Endocrinology 2016; 157:1430-42. [PMID: 26812158 PMCID: PMC4816730 DOI: 10.1210/en.2015-1745] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aging is associated with attenuated ghrelin signaling. During aging, chronic caloric restriction (CR) produces health benefits accompanied by enhanced ghrelin production. Ghrelin receptor (GH secretagogue receptor 1a) agonists administered to aging rodents and humans restore the young adult phenotype; therefore, we tested the hypothesis that the metabolic benefits of CR are mediated by endogenous ghrelin. Three month-old male mice lacking ghrelin (Ghrelin-/-) or ghrelin receptor (Ghsr-/-), and their wild-type (WT) littermates were randomly assigned to 2 groups: ad libitum (AL) fed and CR, where 40% food restriction was introduced gradually to allow Ghrelin-/- and Ghsr-/- mice to metabolically adapt and avoid severe hypoglycemia. Twelve months later, plasma ghrelin, metabolic parameters, ambulatory activity, hypothalamic and liver gene expression, as well as body composition were measured. CR increased plasma ghrelin and des-acyl ghrelin concentrations in WT and Ghsr-/- mice. CR of WT, Ghsr-/-, and Ghrelin-/- mice markedly improved metabolic flexibility, enhanced ambulatory activity, and reduced adiposity. Inactivation of Ghrelin or Ghsr had no effect on AL food intake or food anticipatory behavior. In contrast to the widely held belief that endogenous ghrelin regulates food intake, CR increased expression of hypothalamic Agrp and Npy, with reduced expression of Pomc across genotypes. In the AL context, ablation of ghrelin signaling markedly inhibited liver steatosis, which correlated with reduced Pparγ expression and enhanced Irs2 expression. Although CR and administration of GH secretagogue receptor 1a agonists both benefit the aging phenotype, we conclude the benefits of chronic CR are a consequence of enhanced metabolic flexibility independent of endogenous ghrelin or des-acyl ghrelin signaling.
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Affiliation(s)
- Nicole H Rogers
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Heidi Walsh
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Oscar Alvarez-Garcia
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Seongjoon Park
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Bruce Gaylinn
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Michael O Thorner
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
| | - Roy G Smith
- Department of Metabolism and Aging (N.H.R., H.W., O.A.-G., S.P., R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458; and Division of Endocrinology and Metabolism (B.G., M.O.T.), Department of Medicine, University of Virginia, Charlottesville, Virginia 22908
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5
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Wójcik-Gładysz A, Wańkowska M, Gajewska A, Misztal T, Zielińska-Górska M, Szlis M, Polkowska J. Effects of intracerebroventricular infusions of ghrelin on secretion of follicle-stimulating hormone in peripubertal female sheep. Reprod Fertil Dev 2016; 28:2065-2074. [DOI: 10.1071/rd16028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/23/2016] [Indexed: 12/18/2022] Open
Abstract
Reproduction depends on mechanisms responsible for the regulation of energy homeostasis and puberty is a developmental period when reproductive and somatic maturity are achieved. Ghrelin affects the activity of the hypothalamo–pituitary–gonadal axis under conditions of energy insufficiency. An in vivo model based on intracerebroventricular (i.c.v.) infusions was used to determine whether centrally administered acyl ghrelin affects transcriptional and translational activity of FSH in peripubertal lambs and whether ghrelin administration mimics the effects of short-term fasting. Standard-fed lambs received either Ringer–Lock (R-L) solution (120 µL h–1) or ghrelin (120 µL h–1, 100 µg day–1). Animals experiencing a short-term (72 h) fast were treated only with R-L solution. In each experimental group, i.c.v. infusions occurred for 3 consecutive days. Immunohistochemistry, in situ hybridisation and real-time reverse transcription quantitative polymerase chain reaction analyses revealed that short-term fasting, as well as exogenous acyl ghrelin administration to standard-fed peripubertal lambs, augmented FSHβ mRNA expression and immunoreactive FSH accumulation. In addition to the effects of ghrelin on FSH synthesis in standard-fed animals, effects on gonadotrophin release were also observed. Acyl ghrelin increased the pulse amplitude for gonadotrophin release, which resulted in an elevation in mean serum FSH concentrations. In conclusion, the present data suggest that ghrelin participates in an endocrine network that modulates gonadotrophic activity in peripubertal female sheep.
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6
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François M, Barde S, Achamrah N, Breton J, do Rego JC, Coëffier M, Hökfelt T, Déchelotte P, Fetissov SO. The number of preproghrelin mRNA expressing cells is increased in mice with activity-based anorexia. Neuropeptides 2015; 51:17-23. [PMID: 25963530 DOI: 10.1016/j.npep.2015.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/02/2015] [Accepted: 04/16/2015] [Indexed: 12/30/2022]
Abstract
Plasma levels of ghrelin, an orexigenic peptide, are increased during conditions of chronic starvation, such as in patients with anorexia nervosa. However, it is not known whether such increase can be related to the number of preproghrelin mRNA-expressing cells in the stomach, and if chronic starvation may activate a tentative central ghrelin production. In this work, in situ hybridization technique was used to analyze the presence and number of preproghrelin mRNA-expressing cells in the stomach and the hypothalamus of mice with activity-based anorexia (ABA) induced by the combination of running wheel activity with progressive, during 10 days, feeding-time restriction (FTR) and compared with sedentary FTR, ABA pair-fed (PF) and ad libitum-fed control mice. All food-restricted mice lost more than 20% of body weight. Body weight loss was similar in ABA and PF mice, but it was more pronounced than in FTR mice. Food intake was also lower in ABA than in FTR mice. Preproghrelin mRNA-expressing cells in the stomach were increased proportionally to the body weight loss in all food-restricted groups with the highest number in ABA mice. No preproghrelin mRNA-producing cells were detectable in the hypothalamus of either control or food-restricted mice. Thus, the increased number of gastric preproghrelin mRNA-producing cells during chronic starvation proportionally to the body weight loss and reduced food intake may underlie increased plasma ghrelin. Hyperactivity-induced anorexia appears to further increase the number of preproghrelin mRNA-producing cells in the stomach. No evidence was found for ghrelin expression in the hypothalamus, not even in any of the present experimental models.
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Affiliation(s)
- Marie François
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Stockholm, 17177, Sweden
| | - Najate Achamrah
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France; Department of Nutrition, Rouen University Hospital, CHU Charles Nicolle, Rouen, 76183, France
| | - Jonathan Breton
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France
| | - Jean-Claude do Rego
- Animal Behavior Platform (SCAC), Rouen, 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France
| | - Moïse Coëffier
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France; Department of Nutrition, Rouen University Hospital, CHU Charles Nicolle, Rouen, 76183, France
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, 17177, Sweden
| | - Pierre Déchelotte
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France; Department of Nutrition, Rouen University Hospital, CHU Charles Nicolle, Rouen, 76183, France
| | - Sergueï O Fetissov
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, 76183, France.
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7
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Patton DF, Katsuyama ÂM, Pavlovski I, Michalik M, Patterson Z, Parfyonov M, Smit AN, Marchant EG, Chung J, Abizaid A, Storch KF, de la Iglesia H, Mistlberger RE. Circadian mechanisms of food anticipatory rhythms in rats fed once or twice daily: clock gene and endocrine correlates. PLoS One 2014; 9:e112451. [PMID: 25502949 PMCID: PMC4263600 DOI: 10.1371/journal.pone.0112451] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/07/2014] [Indexed: 12/20/2022] Open
Abstract
Circadian clocks in many brain regions and peripheral tissues are entrained by the daily rhythm of food intake. Clocks in one or more of these locations generate a daily rhythm of locomotor activity that anticipates a regular mealtime. Rats and mice can also anticipate two daily meals. Whether this involves 1 or 2 circadian clocks is unknown. To gain insight into how the circadian system adjusts to 2 daily mealtimes, male rats in a 12∶12 light-dark cycle were fed a 2 h meal either 4 h after lights-on or 4 h after lights-off, or a 1 h meal at both times. After 30 days, brain, blood, adrenal and stomach tissue were collected at 6 time points. Multiple clock genes from adrenals and stomachs were assayed by RT-PCR. Blood was assayed for corticosterone and ghrelin. Bmal1 expression was quantified in 14 brain regions by in situ hybridization. Clock gene rhythms in adrenal and stomach from day-fed rats oscillated in antiphase with the rhythms in night-fed rats, and at an intermediate phase in rats fed twice daily. Corticosterone and ghrelin in 1-meal rats peaked at or prior to the expected mealtime. In 2-meal rats, corticosterone peaked only prior the nighttime meal, while ghrelin peaked prior to the daytime meal and then remained elevated. The olfactory bulb, nucleus accumbens, dorsal striatum, cerebellum and arcuate nucleus exhibited significant daily rhythms of Bmal1 in the night-fed groups that were approximately in antiphase in the day-fed groups, and at intermediate levels (arrhythmic) in rats anticipating 2 daily meals. The dissociations between anticipatory activity and the peripheral clocks and hormones in rats anticipating 2 daily meals argue against a role for these signals in the timing of behavioral rhythms. The absence of rhythmicity at the tissue level in brain regions from rats anticipating 2 daily meals support behavioral evidence that circadian clock cells in these tissues may reorganize into two populations coupled to different meals.
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Affiliation(s)
- Danica F. Patton
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | - Ângela M. Katsuyama
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | - Ilya Pavlovski
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | - Mateusz Michalik
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | | | - Maksim Parfyonov
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | - Andrea N. Smit
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | | | - John Chung
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | - Horacio de la Iglesia
- Department of Biology, University of Washington, Seattle, WA, United States of America
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Abstract
Individual meals are products of a complex interaction of signals related to both short-term and long-term availability of energy stores. In addition to maintaining the metabolic demands of the individual in the short term, levels of energy intake must also maintain and defend body weight over longer periods. To accomplish this, satiety pathways are regulated by a sophisticated network of endocrine and neuroendocrine pathways. Higher brain centers modulate meal size through descending inputs to caudal brainstem regions responsible for the motor pattern generators associated with ingestion. Gastric and intestinal signals interact with central nervous system pathways to terminate food intake. These inputs can be modified as a function of internal metabolic signals, external environmental influences, and learning to regulate meal size.
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9
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Méquinion M, Langlet F, Zgheib S, Dickson S, Dehouck B, Chauveau C, Viltart O. Ghrelin: central and peripheral implications in anorexia nervosa. Front Endocrinol (Lausanne) 2013; 4:15. [PMID: 23549309 PMCID: PMC3581855 DOI: 10.3389/fendo.2013.00015] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 02/01/2013] [Indexed: 11/15/2022] Open
Abstract
Increasing clinical and therapeutic interest in the neurobiology of eating disorders reflects their dramatic impact on health. Chronic food restriction resulting in severe weight loss is a major symptom described in restrictive anorexia nervosa (AN) patients, and they also suffer from metabolic disturbances, infertility, osteopenia, and osteoporosis. Restrictive AN, mostly observed in young women, is the third largest cause of chronic illness in teenagers of industrialized countries. From a neurobiological perspective, AN-linked behaviors can be considered an adaptation that permits the endurance of reduced energy supply, involving central and/or peripheral reprograming. The severe weight loss observed in AN patients is accompanied by significant changes in hormones involved in energy balance, feeding behavior, and bone formation, all of which can be replicated in animals models. Increasing evidence suggests that AN could be an addictive behavior disorder, potentially linking defects in the reward mechanism with suppressed food intake, heightened physical activity, and mood disorder. Surprisingly, the plasma levels of ghrelin, an orexigenic hormone that drives food-motivated behavior, are increased. This increase in plasma ghrelin levels seems paradoxical in light of the restrained eating adopted by AN patients, and may rather result from an adaptation to the disease. The aim of this review is to describe the role played by ghrelin in AN focusing on its central vs. peripheral actions. In AN patients and in rodent AN models, chronic food restriction induces profound alterations in the « ghrelin » signaling that leads to the development of inappropriate behaviors like hyperactivity or addiction to food starvation and therefore a greater depletion in energy reserves. The question of a transient insensitivity to ghrelin and/or a potential metabolic reprograming is discussed in regard of new clinical treatments currently investigated.
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Affiliation(s)
- Mathieu Méquinion
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
| | - Fanny Langlet
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
| | - Sara Zgheib
- Pathophysiology of inflammatory of bone diseases, Université Lille Nord de France-ULCO – Lille 2Boulogne sur Mer, France
| | - Suzanne Dickson
- Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
- Department of Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Bénédicte Dehouck
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
- Université Lille Nord de France – Université d’ArtoisLiévin, France
| | - Christophe Chauveau
- Pathophysiology of inflammatory of bone diseases, Université Lille Nord de France-ULCO – Lille 2Boulogne sur Mer, France
| | - Odile Viltart
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
- Université Lille Nord de France-USTL (Lille 1)Villeneuve d’Ascq, France
- *Correspondence: Odile Viltart, Development and Plasticity of the Postnatal Brain, Team 2, Jean-Pierre Aubert Research Center, UMR INSERM 837, Bât Biserte, 1 place de Verdun, 59,045 Lille cedex, France. e-mail:
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Cardona Cano S, Merkestein M, Skibicka KP, Dickson SL, Adan RAH. Role of ghrelin in the pathophysiology of eating disorders: implications for pharmacotherapy. CNS Drugs 2012; 26:281-96. [PMID: 22452525 DOI: 10.2165/11599890-000000000-00000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ghrelin is the only known circulating orexigenic hormone. It increases food intake by interacting with hypothalamic and brainstem circuits involved in energy balance, as well as reward-related brain areas. A heightened gut-brain ghrelin axis is an emerging feature of certain eating disorders such as anorexia nervosa and Prader-Willi syndrome. In common obesity, ghrelin levels are lowered, whereas post-meal ghrelin levels remain higher than in lean individuals. Agents that interfere with ghrelin signalling have therapeutic potential for eating disorders, including obesity. However, most of these drugs are only in the preclinical phase of development. Data obtained so far suggest that ghrelin agonists may have potential in the treatment of anorexia nervosa, while ghrelin antagonists seem promising for other eating disorders such as obesity and Prader-Willi syndrome. However, large clinical trials are needed to evaluate the efficacy and safety of these drugs.
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