1
|
Viral Infection Drives the Regulation of Feeding Behavior Related Genes in Salmo salar. Int J Mol Sci 2021; 22:ijms222111391. [PMID: 34768822 PMCID: PMC8583931 DOI: 10.3390/ijms222111391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/26/2021] [Accepted: 09/03/2021] [Indexed: 11/16/2022] Open
Abstract
The feeding behavior in fish is a complex activity that relies on the ability of the brain to integrate multiple signals to produce appropriate responses in terms of food intake, energy expenditure, and metabolic activity. Upon stress cues including viral infection or mediators such as the proinflammatory cytokines, prostaglandins, and cortisol, both Pomc and Npy/Agrp neurons from the hypothalamus are stimulated, thus triggering a response that controls both energy storage and expenditure. However, how appetite modulators or neuro-immune cues link pathogenesis and energy homeostasis in fish remains poorly understood. Here, we provide the first evidence of a molecular linkage between inflammation and food intake in Salmon salar. We show that in vivo viral challenge with infectious pancreatic necrosis virus (IPNV) impacts food consumption by activating anorexic genes such as mc4r, crf, and pomcb and 5-HT in the brain of S. salar. At the molecular level, viral infection induces an overall reduction in lipid content in the liver, favoring the production of AA and EPA associated with the increment of elovl2 gene. In addition, infection upregulates leptin signaling and inhibits insulin signaling. These changes are accompanied by a robust inflammatory response represented by the increment of Il-1b, Il-6, Tnfa, and Pge2 as well as an increased cortisol level in vivo. Thus, we propose a model in which hypothalamic neurons respond to inflammatory cytokines and stress-related molecules and interact with appetite induction/inhibition. These findings provide evidence of crosstalk between pathogenesis-driven inflammation and hypothalamic-pituitary-adrenocortical axes in stress-induced food intake behavior in fish.
Collapse
|
2
|
Deng Y, Deng G, Grobe JL, Cui H. Hypothalamic GPCR Signaling Pathways in Cardiometabolic Control. Front Physiol 2021; 12:691226. [PMID: 34262481 PMCID: PMC8274634 DOI: 10.3389/fphys.2021.691226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 05/26/2021] [Indexed: 01/22/2023] Open
Abstract
Obesity is commonly associated with sympathetic overdrive, which is one of the major risk factors for the development of cardiovascular diseases, such as hypertension and heart failure. Over the past few decades, there has been a growing understanding of molecular mechanisms underlying obesity development with central origin; however, the relative contribution of these molecular changes to the regulation of cardiovascular function remains vague. A variety of G-protein coupled receptors (GPCRs) and their downstream signaling pathways activated in distinct hypothalamic neurons by different metabolic hormones, neuropeptides and monoamine neurotransmitters are crucial not only for the regulation of appetite and metabolic homeostasis but also for the sympathetic control of cardiovascular function. In this review, we will highlight the main GPCRs and associated hypothalamic nuclei that are important for both metabolic homeostasis and cardiovascular function. The potential downstream molecular mediators of these GPCRs will also be discussed.
Collapse
Affiliation(s)
- Yue Deng
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Guorui Deng
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Justin L. Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Huxing Cui
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, United States
- FOE Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, United States
- Obesity Research and Educational Initiative, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| |
Collapse
|
3
|
Higher HbA1c levels associate with lower hippocampal serotonin transporter availability in non-diabetic adults with obesity. Sci Rep 2020; 10:21383. [PMID: 33288788 PMCID: PMC7721891 DOI: 10.1038/s41598-020-78227-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/27/2020] [Indexed: 11/30/2022] Open
Abstract
The current study aimed to investigate whether the in vivo availability of central serotonin reuptake transporters (5-HTT) is associated with plasma levels of glycosylated hemoglobin (HbA1c) in non-diabetic humans with obesity. 5-HTT availability was measured by using positron emission tomography (PET) imaging with the 5-HTT selective radiotracer [11C]DASB in 23 non-diabetic individuals with obesity and 14 healthy, non-obesity controls. Parametric images of binding potential BPND were generated from the PET data and analyzed together with HbA1c levels by using volume of interest analysis for brain areas relevant to appetite control. Voxel-based morphometry (VBM) of individual magnetic resonance imaging data was further performed to correlate grey matter density (GMD) maps with HbA1c. We found significant negative correlations between HbA1c levels and BPND in right and left hippocampus in obesity (r = − 0.717, p < 0.001, and r = − 0.557, p = 0.006, respectively). VBM analyses revealed that higher HbA1c levels were associated with GMD in the right para-hippocampal area. Our results indicate that chronically high blood glucose levels may evoke changes in hippocampal 5-HTT levels that are in part tied to local microstructure.
Collapse
|
4
|
Versteeg RI, Serlie MJ, Kalsbeek A, la Fleur SE. Serotonin, a possible intermediate between disturbed circadian rhythms and metabolic disease. Neuroscience 2015; 301:155-67. [PMID: 26047725 DOI: 10.1016/j.neuroscience.2015.05.067] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/21/2015] [Accepted: 05/27/2015] [Indexed: 01/27/2023]
Abstract
It is evident that eating in misalignment with the biological clock (such as in shift work, eating late at night and skipping breakfast) is associated with increased risk for obesity and diabetes. The biological clock located in the suprachiasmatic nucleus dictates energy balance including feeding behavior and glucose metabolism. Besides eating and sleeping patterns, glucose metabolism also exhibits clear diurnal variations with higher blood glucose concentrations, glucose tolerance and insulin sensitivity prior to waking up. The daily variation in plasma glucose concentrations in rats, is independent of the rhythm in feeding behavior. On the other hand, feeding itself has profound effects on glucose metabolism, but differential effects occur depending on the time of the day. We here review data showing that a disturbed diurnal eating pattern results in alterations in glucose metabolism induced by a disrupted circadian clock. We first describe the role of central serotonin on feeding behavior and glucose metabolism and subsequently describe the effects of central serotonin on the circadian system. We next explore the interaction between the serotonergic system and the circadian clock in conditions of disrupted diurnal rhythms in feeding and how this might be involved in the metabolic dysregulation that occurs with chronodisruption.
Collapse
Affiliation(s)
- R I Versteeg
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - M J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - A Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - S E la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| |
Collapse
|
5
|
Voigt JP, Fink H. Serotonin controlling feeding and satiety. Behav Brain Res 2015; 277:14-31. [DOI: 10.1016/j.bbr.2014.08.065] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 02/06/2023]
|
6
|
la Fleur SE, Serlie MJ. The interaction between nutrition and the brain and its consequences for body weight gain and metabolism; studies in rodents and men. Best Pract Res Clin Endocrinol Metab 2014; 28:649-59. [PMID: 25256761 DOI: 10.1016/j.beem.2014.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aberrant feeding behavior can lead to obesity and obesity-related medical consequences, such as insulin resistance and diabetes. Although alterations in glucose metabolism (i.e. insulin resistance), in the presence of excessive fat tissue are often explained by the consequences of dysfunctional adipose tissue, evidence is emerging that also altered brain functions might be an important determinant of insulin resistance. In this review, we provide an overview of how feeding behavior and obesity interact with brain circuitry and how these interactions affect glucose metabolism. Because brain circuitries involved in food intake have been shown to partly control glucose metabolism as well, targeting these circuitries in obese subjects might not only affect food intake and body weight but also glucose metabolism.
Collapse
Affiliation(s)
- Susanne E la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreeg 9, F2-154, 1105 AZ Amsterdam, The Netherlands.
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreeg 9, F2-154, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
7
|
Marston OJ, Garfield AS, Heisler LK. Role of central serotonin and melanocortin systems in the control of energy balance. Eur J Pharmacol 2011; 660:70-9. [DOI: 10.1016/j.ejphar.2010.12.024] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 12/22/2010] [Indexed: 11/28/2022]
|
8
|
Hainer V. Comparative efficiency and safety of pharmacological approaches to the management of obesity. Diabetes Care 2011; 34 Suppl 2:S349-54. [PMID: 21525481 PMCID: PMC3632205 DOI: 10.2337/dc11-s255] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Vojtech Hainer
- Institute of Endocrinology, Obesity Management Center, Prague, Czech Republic.
| |
Collapse
|
9
|
Magalhães CP, de Freitas MFL, Nogueira MI, Campina RCDF, Takase LF, de Souza SL, de Castro RM. Modulatory role of serotonin on feeding behavior. Nutr Neurosci 2011; 13:246-55. [PMID: 21040622 DOI: 10.1179/147683010x12611460764723] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The appearance, the odor, and the flavor of foods, all send messages to the encephalic area of the brain. The hypothalamus, in particular, plays a key role in the mechanisms that control the feeding behavior. These signals modulate the expression and the action of anorexigenic or orexigenic substances that influence feeding behavior. The serotonergic system of neurotransmission consists of neurons that produce and liberate serotonin as well as the serotonin-specific receptor. It has been proven that some serotonergic drugs are effective in modulating the mechanisms of control of feeding behavior. Obesity and its associated illnesses have become significant public health problems. Some drugs that manipulate the serotonergic systems have been demonstrated to be effective interventions in the treatment of obesity. The complex interplay between serotonin and its receptors, and the resultant effects on feeding behavior have become of great interest in the scientific community.
Collapse
Affiliation(s)
- Carolina Peixoto Magalhães
- Centro Acadêmico de Vitoria/Universidade Federal de Pernambuco, Rua do Alto do Reservatório, S/N - Bela Vista - CEP 55608-680, Vitória de Santo Antão, PE, Brasil.
| | | | | | | | | | | | | |
Collapse
|
10
|
Lam DD, Garfield AS, Marston OJ, Shaw J, Heisler LK. Brain serotonin system in the coordination of food intake and body weight. Pharmacol Biochem Behav 2010; 97:84-91. [PMID: 20837046 DOI: 10.1016/j.pbb.2010.09.003] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 08/02/2010] [Accepted: 09/06/2010] [Indexed: 11/30/2022]
Abstract
An inverse relationship between brain serotonin and food intake and body weight has been known for more than 30 years. Specifically, augmentation of brain serotonin inhibits food intake, while depletion of brain serotonin promotes hyperphagia and weight gain. Through the decades, serotonin receptors have been identified and their function in the serotonergic regulation of food intake clarified. Recent refined genetic studies now indicate that a primary mechanism through which serotonin influences appetite and body weight is via serotonin 2C receptor (5-HT(2C)R) and serotonin 1B receptor (5-HT(1B)R) influencing the activity of endogenous melanocortin receptor agonists and antagonists at the melanocortin 4 receptor (MC4R). However, other mechanisms are also possible and the challenge of future research is to delineate them in the complete elucidation of the complex neurocircuitry underlying the serotonergic control of appetite and body weight.
Collapse
Affiliation(s)
- Daniel D Lam
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | | | | | | | | |
Collapse
|
11
|
Ota K, Wildmann J, Ota T, Besedovsky HO, Del Rey A. Interleukin-1beta and insulin elicit different neuroendocrine responses to hypoglycemia. Ann N Y Acad Sci 2009; 1153:82-8. [PMID: 19236331 DOI: 10.1111/j.1749-6632.2008.03981.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interleukin (IL)-1beta induces a prolonged hypoglycemia in mice that is not caused by a reduction in food intake and is dissociable from insulin effects. There is a peripheral component in the hypoglycemia that the cytokine induces resulting from an increased glucose uptake, an effect that can be exerted in a paracrine fashion at the site where IL-1 is locally produced. However, the maintenance of hypoglycemia is controlled at brain levels because the blockade of IL-1 receptors in the central nervous system inhibits this effect to a large extent. Furthermore, there is evidence that the cytokine interferes with counter regulation to hypoglycemia. Here we report that administration of IL-1 or long-lasting insulin results in different changes in food intake and in neuroendocrine mechanisms 8 h following induction of the same degree of hypoglycemia (40-45% decrease in glucose blood levels). Insulin, but not IL-1, caused an increase in food intake and an endocrine response that tends to reestablish euglycemia. Conversely, a decrease in noradrenergic and an increase in serotonergic activity in the hypothalamus occur in parallel with a reduction of glucose blood levels only in IL-1-treated mice, effects that can contribute to the maintenance of hypoglycemia. These results are compatible with the proposal that IL-1 acting in the brain can reset glucose homeostasis at a lower level. The biologic significance of this effect is discussed.
Collapse
Affiliation(s)
- Kazuki Ota
- Department of Immunophysiology, Institute of Physiology and Pathophysiology, Medical Faculty, Philipps University, Marburg, Germany
| | | | | | | | | |
Collapse
|
12
|
Lam DD, Przydzial MJ, Ridley SH, Yeo GSH, Rochford JJ, O'Rahilly S, Heisler LK. Serotonin 5-HT2C receptor agonist promotes hypophagia via downstream activation of melanocortin 4 receptors. Endocrinology 2008; 149:1323-8. [PMID: 18039773 PMCID: PMC2275368 DOI: 10.1210/en.2007-1321] [Citation(s) in RCA: 210] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The neurotransmitter serotonin (5-hydroxytryptamine) is a well-established modulator of energy balance. Both pharmacological and genetic evidence implicate the serotonin 2C receptor (5-HT(2C)R) as a critical receptor mediator of serotonin's effects on ingestive behavior. Here we characterized the effect of the novel and selective 5-HT(2C)R agonist BVT.X on energy balance in obese and lean mice and report that BVT.X significantly reduces acute food intake without altering locomotor activity or oxygen consumption. In an effort to elucidate the mechanism of this effect, we examined the chemical phenotype of 5-HT(2C)R-expressing neurons in a critical brain region affecting feeding behavior, the arcuate nucleus of the hypothalamus. We show that 5-HT(2C)Rs are coexpressed with neurons containing proopiomelanocortin, known to potently affect appetite, in the arcuate nucleus of the hypothalamus of the mouse. We then demonstrate that prolonged infusion with BVT.X in obese mice significantly increases Pomc mRNA and reduces body weight, percent body fat, and initial food intake. To evaluate the functional importance of melanocortin circuitry in the effect of BVT.X on ingestive behavior, we assessed mice with disrupted melanocortin pathways. We report that mice lacking the melanocortin 4 receptor are not responsive to BVT.X-induced hypophagia, demonstrating that melanocortins acting on melanocortin 4 receptor are a requisite downstream pathway for 5-HT(2C)R agonists to exert effects on food intake. The data presented here not only indicate that the novel 5-HT(2C)R agonist BVT.X warrants further investigation as a treatment for obesity but also elucidate specific neuronal pathways potently affecting energy balance through which 5-HT(2C)R agonists regulate ingestive behavior.
Collapse
MESH Headings
- Adipose Tissue/drug effects
- Adipose Tissue/metabolism
- Animals
- Appetite Depressants/pharmacology
- Appetite Regulation/drug effects
- Appetite Regulation/physiology
- Disease Models, Animal
- Eating/drug effects
- Eating/physiology
- Energy Metabolism/drug effects
- Energy Metabolism/physiology
- Feeding and Eating Disorders/etiology
- Feeding and Eating Disorders/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Obese
- Motor Activity/drug effects
- Motor Activity/physiology
- Oxygen Consumption/drug effects
- Oxygen Consumption/physiology
- Pro-Opiomelanocortin/metabolism
- RNA, Messenger/metabolism
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptor, Serotonin, 5-HT2C/metabolism
- Serotonin/metabolism
- Serotonin 5-HT2 Receptor Agonists
Collapse
Affiliation(s)
- Daniel D Lam
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
13
|
Ramos EJB, Meguid MM, Campos ACL, Coelho JCU. Neuropeptide Y, alpha-melanocyte-stimulating hormone, and monoamines in food intake regulation. Nutrition 2005; 21:269-79. [PMID: 15723758 DOI: 10.1016/j.nut.2004.06.021] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2004] [Revised: 01/25/2004] [Accepted: 06/08/2004] [Indexed: 11/26/2022]
Abstract
Obesity is increasing in severity and prevalence in the United States and represents a major public health issue. No effective pharmacologic treatment leading to sustained weight loss currently exists. The growing interest in the regulation of food intake stems from the current drug treatments for obesity, almost all of which interfere with the monoamine system. Our knowledge of potential interactions between the orexigenic and anorexigenic pathways is limited and fragmented, making the development of targeted drug therapy for obesity difficult. The present review of the interaction of neuropeptides and monoamines emphasizes the complexity of the central mechanisms that regulate feeding behavior. Two main systems are implicated in food intake regulation: neuropeptide Y (NPY) and pro-opiomelanocortin. alpha-Melanocyte-stimulating hormone is a tridecapeptide cleaved from pro-opiomelanocortin that acts to inhibit food intake. The predominant NPY orexigenic receptors are NPY-Y1 and NPY-Y5, and the two anorexigenic melanocortin receptors involved in hypothalamic food intake control are MC3-R and MC4-R. Both neuropeptides interact with monoamines in the hypothalamus to control physiologic states such as hunger, satiation, and satiety. Serotonin suppresses food intake and body weight, acting mainly through the serotonin 1B receptor. Dopamine regulates hunger and satiety by acting in specific hypothalamic areas, through the D1 and D2 receptors. Noradrenaline activation of alpha1- and beta2-adrenoceptors decreases food intake, and stimulation of the alpha2-adrenoceptor increases food intake. A better understanding of the detailed mechanisms underlying the pathogenesis of hyperphagia and hypophagia is needed to develop new therapeutic approaches to obesity.
Collapse
Affiliation(s)
- Eduardo J B Ramos
- Surgical Metabolism and Nutrition Laboratory, Department of Surgery, University Hospital, Upstate Medical University, Syracuse, New York, USA
| | | | | | | |
Collapse
|
14
|
Affiliation(s)
- Tamas L Horvath
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street FMB 339, New Haven, Connecticut 06520, USA.
| | | |
Collapse
|
15
|
Heisler LK, Cowley MA, Tecott LH, Fan W, Low MJ, Smart JL, Rubinstein M, Tatro JB, Marcus JN, Holstege H, Lee CE, Cone RD, Elmquist JK. Activation of central melanocortin pathways by fenfluramine. Science 2002; 297:609-11. [PMID: 12142539 DOI: 10.1126/science.1072327] [Citation(s) in RCA: 342] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
D-fenfluramine (d-FEN) was once widely prescribed and was among the most effective weight loss drugs, but was withdrawn from clinical use because of reports of cardiac complications in a subset of patients. Discerning the neurobiology underlying the anorexic action of d-FEN may facilitate the development of new drugs to prevent and treat obesity. Through a combination of functional neuroanatomy, feeding, and electrophysiology studies in rodents, we show that d-FEN-induced anorexia requires activation of central nervous system melanocortin pathways. These results provide a mechanistic explanation of d-FEN's anorexic actions and indicate that drugs targeting these downstream melanocortin pathways may prove to be effective and more selective anti-obesity treatments.
Collapse
MESH Headings
- Animals
- Appetite Depressants/pharmacology
- Arcuate Nucleus of Hypothalamus/drug effects
- Arcuate Nucleus of Hypothalamus/metabolism
- Feeding Behavior/drug effects
- Fenfluramine/pharmacology
- Male
- Melanocyte-Stimulating Hormones/pharmacology
- Mice
- Mice, Obese
- Mice, Transgenic
- Neurons/drug effects
- Neurons/metabolism
- Paraventricular Hypothalamic Nucleus/drug effects
- Paraventricular Hypothalamic Nucleus/metabolism
- Patch-Clamp Techniques
- Pro-Opiomelanocortin/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Melanocortin, Type 3
- Receptor, Melanocortin, Type 4
- Receptor, Serotonin, 5-HT2C
- Receptors, Corticotropin/metabolism
- Receptors, Serotonin/metabolism
- Serotonin/metabolism
- Serotonin Agents/pharmacology
- alpha-MSH/metabolism
Collapse
Affiliation(s)
- Lora K Heisler
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Affiliation(s)
- Susan Z Yanovski
- Division of Digestive Diseases and Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-5450, USA.
| | | |
Collapse
|
17
|
Abstract
The regulation of energy balance is enormously complex, with numerous genetic, hormonal, neural/behavioral, and societal influences. Although the current epidemic of obesity has its underpinnings in the changes in culture during the last half century, the role of the neuroendocrine system in the genesis of obesity is physiologically and therapeutically unavoidable. Increased understanding of this system has suggested organic etiologies (and therapies) for some rare and not-so-rare forms of obesity. With so many inputs, it is not implausible that dysfunction of other parts of this feedback system will be found to explain other forms of obesity in the future. Fortunately or unfortunately, diet and exercise remain the mainstays of obesity therapy. Most diet-exercise programs result in an acute 11-kg weight loss in adults; the question is whether it can be sustained without significant long-term behavior modification. In the European Sibutramine Trial of Obesity Reduction and Maintenance (STORM), 42% of treated patients dropped out; of those remaining, 77% of subjects lost more than 5% of initial body weight, but only 43% of these individuals maintained greater than 80% of this loss over 2 years. Could there be an organic component in persons who do not respond? Obesity pharmacotherapies sometimes have beneficial acute effects, but these effects are impermanent; discontinuation tends to result in a rebound weight gain, suggesting that the etiology of the obesity is still present. A useful guiding principle is that patients who do not respond to diet and exercise should undergo an initial medical evaluation, including assessments of birth weight, past medical history, weight history, family history, diet, exercise, and fasting insulin and thyroid levels. As the nosology of obesity improves, diagnostic efficiency and therapeutic success should increase, leading to a decrease in associated morbidity, mortality, and socioeconomic ramifications.
Collapse
Affiliation(s)
- R H Lustig
- Division of Endocrinology, Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA.
| |
Collapse
|
18
|
Abstract
The regulation of energy balance is enormously complex, with numerous genetic, hormonal, neural and behavioral, and societal influences. Although the current epidemic of obesity clearly has its underpinnings in the changes in culture during the past half-century (see other articles in this issue), the role of the neuroendocrine system in the genesis of obesity, as described in this article, is physiologically and therapeutically unavoidable. An understanding of this system has suggested organic causes (and therapies) for some rare and not-so-rare forms of obesity. With so many inputs, it is not far-fetched to assume that dysfunction of other parts of this feedback system will be found to explain other forms of obesity in the future. What does this mean for obese children entering the pediatrician's office? Fortunately or unfortunately, diet and exercise are the mainstays of obesity therapy for children and adults. Most diet-exercise programs result in an acute 11-kg weight loss in adults; the question is whether it can be sustained without significant long-term behavioral modification. For instance, the European Sibutramine Trial of Obesity Reduction and Maintenance trial showed that 42% of treated subjects drop out; of those remaining, 77% of subjects lost more than 5% of initial body weight, but only 43% of those maintained more than 80% of this over 2 years. Could there be an organic component in those who do not respond? Of course, obesity pharmacotherapies sometimes have beneficial acute effects, but these drugs work for only as long as they are consumed; discontinuation tends to result in a "rebound" weight gain, suggesting that the cause of the obesity is still present. Furthermore, in 2001, there are no obesity drugs approved for children. A useful guiding principle is that children deserve at the minimum an initial medical evaluation, including birth weight, medical history, family history, dietary evaluation, and exercise assessment. Perhaps the most important feature that can distinguish "organic" from "behavioral" weight gain in childhood is the age of the "adiposity rebound." The Centers for Disease Control and Prevention now supplies BMI charts for boys and girls at www.cdc.gov/growthcharts. Plotting of the BMI versus age allows pediatricians to determine the age at which the BMI starts to increase (mean, 5.5 years). The earlier the adiposity rebound, the more likely the child will be obese as an adult, and the more likely that an organic cause can be determined. In such patients, thyroid levels and fasting insulin and leptin levels should be measured. An initial attempt at diet and exercise is essential; patients who do not respond with BMI stabilization should be investigated for a more ominous cause of their obesity. As the nosology of obesity improves, pediatricians will be able to increase the diagnostic efficiency and therapeutic success of this unfortunate, debilitating, and expensive epidemic.
Collapse
Affiliation(s)
- R H Lustig
- Division of Endocrinology and Metabolism, Departments of Pediatrics and Anatomy and Neurobiology, University of Tennessee Health Science Center and St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
| |
Collapse
|
19
|
Abstract
Obesity is a well-known risk factor for the development of Type 2 diabetes mellitus. The management of the obese diabetic patient remains a challenge for the clinician but, in any case, weight reduction should be considered as a key objective. In this respect, several antiobesity drugs have demonstrated potential. However, while fenfluramine and dexfenfluramine have been shown to promote weight loss and to directly improve insulin sensitivity, being two mechanisms contributing to better blood glucose control in obese Type 2 diabetic patients, they were recently withdrawn due to safety problems. Sibutramine, a new selective norepinephrine and serotonin reuptake inhibitor, promotes weight loss by decreasing food intake, an effect which leads to a mild improvement (significant in patients losing > or =5% of initial body weight) of blood glucose control in obese diabetic patients. Similarly, orlistat, a selective gastrointestinal lipase inhibitor which increases faecal fat losses, enhances diet-induced weight reduction and improves both blood glucose control and vascular risk profile, especially dyslipidaemia, in obese Type 2 diabetic patients. Further studies are required to better identify good responders to pharmacotherapy and specify the role of antiobesity agents in the overall long-term management of obese subjects with Type 2 diabetes. Other novel pharmacological approaches deserve further consideration, for instance beta-3 agonists aiming to increase energy expenditure, drugs interfering with tumor necrosis factor-alpha (TNF-alpha) or free fatty acid release by the adipose tissue or agents that slow gastric emptying. However, until now, results regarding efficacy and/or safety have been disappointing or preliminary in humans.
Collapse
Affiliation(s)
- A J Scheen
- Division of Diabetes, Nutrition and Metabolic Diseases, Department of Medicine, University of Liège, CHU Sart Tilman, B-4000 Liège 1, Belgium.
| | | |
Collapse
|
20
|
Affiliation(s)
- G A Bray
- Louisiana State University, Pennington Biomedical Research Center, Baton Rouge 70808-4124, USA
| | | |
Collapse
|
21
|
Lustig RH, Rose SR, Burghen GA, Velasquez-Mieyer P, Broome DC, Smith K, Li H, Hudson MM, Heideman RL, Kun LE. Hypothalamic obesity caused by cranial insult in children: altered glucose and insulin dynamics and reversal by a somatostatin agonist. J Pediatr 1999; 135:162-8. [PMID: 10431109 DOI: 10.1016/s0022-3476(99)70017-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Hypothalamic obesity is a rare sequela of cranial insult, for which pathogenesis and treatment remain obscure. In rodents ventromedial hypothalamic damage causes hyperphagia, obesity, hyperinsulinism, and insulin resistance. Reduction of insulin secretion in humans may attenuate weight gain. METHODS Eight children with intractable obesity after therapy for leukemia or brain tumors underwent oral glucose tolerance testing (OGTT) with simultaneous insulin levels before and after treatment with octreotide for 6 months. RESULTS In comparison with a 6-month pre-study observation period, patients exhibited weight loss (+6.0 +/- 0.7 kg vs -4.8 +/- 1.8 kg; P =.04) and decrease in body mass index (+2.1 +/- 0.3 kg/m(2) vs -2.0 +/- 0.7 kg/m(2); P =.0001). Recall calorie count decreased during the 6 months of treatment (P =. 015). OGTT demonstrated biochemical glucose intolerance in 5 of 8 patients initially and in 2 of 7 at study end, whereas insulin response was decreased (281 +/- 47 microU/mL vs 114 +/- 35 microU/mL; P =.04). Percent weight change correlated with changes in insulin response (r = 0.72, P =.012) and changes in plasma leptin r = 0.76, P =.0004). CONCLUSIONS Patients with hypothalamic obesity demonstrate excessive insulin secretion. Octreotide administration promoted weight loss, which correlated with reduction in insulin secretion on OGTT and with reduction in leptin levels. Pre-study biochemical glucose tolerance improved in several patients while they were receiving octreotide. These results suggest that normalization of insulin secretion may be an effective therapeutic strategy in this syndrome.
Collapse
Affiliation(s)
- R H Lustig
- Department of Pediatrics, University of Tennessee, Memphis, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Absence of fenfluramine-induced anorexia and reduced c-Fos induction in the hypothalamus and central amygdaloid complex of serotonin 1B receptor knock-out mice. J Neurosci 1998. [PMID: 9651234 DOI: 10.1523/jneurosci.18-14-05537.1998] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fenfluramine, a serotonin releaser and uptake inhibitor, has been widely prescribed as an appetite suppressant. Despite its popular clinical use, however, the precise neural pathways and specific 5-HT receptors that account for its anorectic effect have yet to be elucidated. To test the hypothesis that stimulation of 5-HT1B receptors is required for the anorectic effect of fenfluramine, we assessed food intake in wild-type and 5-HT1B knock-out mice. Next, to determine possible brain structures and pathways that may contribute to the 5-HT1B-mediated effects of fenfluramine, we studied by immunohistochemistry the induction of the immediate early gene c-fos. Although the effect of fenfluramine on locomotion was indistinguishable between both wild-type and 5-HT1B knock-out mice, the anorectic effect of the drug was absent in only the knock-out mice. Furthermore, the induction of c-Fos immunoreactivity found in the paraventricular nucleus of the hypothalamus (PVN) of wild-type mice was substantially reduced in the knock-outs. Induction in the central amygdaloid nucleus (CeA) and in the bed nucleus of the stria terminalis (BNST), although robust in wild-type animals, was completely absent in knock-out animals. The mixed 5-HT1A/1B agonist RU24969 was able to mimic both the hypophagia and c-fos induction elicited by fenfluramine in wild-type mice, but not in the 5-HT1B knock-out mice. Our results thus demonstrate that stimulation of 5-HT1B receptors is required for fenfluramine-induced anorexia and suggest a role for the PVN, CeA, and BNST in mediating this effect.
Collapse
|
23
|
Rose S, Hindmarsh JG, Collins P, Jenner P. The effect of fenfluramine dosage regimen and reduced food intake on levels of 5-HT in rat brain. J Neural Transm (Vienna) 1998; 104:1339-51. [PMID: 9503280 DOI: 10.1007/bf01294735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Male Wistar rats received fenfluramine in subacute (5 mg/kg b.i.d. i.p. for 4 days) or escalating (0.5, 1, 1.5, 2, 3, 4 and 5 mg/kg b.i.d. i.p., each dose given for 4 days) doses. Saline-treated controls received food ad libitum, or were pair-fed with the fenfluramine-treated animals. Rats were killed 1, 15 and 30 days after drug withdrawal. On day 1, plasma and brain fenfluramine levels were higher, and hypothalamus norfenfluramine levels were lower following escalating compared to subacute dosing, although total active drug levels were unaltered. Both treatment regimes, and pair-feeding reduced food intake and body weight. Subacute fenfluramine reduced brain 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels for up to 30 days. Brain 5-HT and 5-HIAA levels were unaltered following escalating-doses of fenfluramine. Additionally, pair-feeding transiently decreased hippocampal 5-HT levels. These data suggest that escalating-doses of fenfluramine prevent the 5-HT-depleting effect of a sub-cute challenge without altering the anorexic action of the drug.
Collapse
Affiliation(s)
- S Rose
- Neurodegenerative Diseases Research Centre, King's College, London, United Kingdom
| | | | | | | |
Collapse
|
24
|
Christensen JD, Babb SM, Cohen BM, Renshaw PF. Quantitation of dexfenfluramine/d-norfenfluramine concentration in primate brain using 19F NMR spectroscopy. Magn Reson Med 1998; 39:149-54. [PMID: 9438448 DOI: 10.1002/mrm.1910390121] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fluorine (19F) magnetic resonance spectroscopy (MRS) was used to quantify the combined concentration of the anorectic drug dexfenfluramine (DF) and its active metabolite d-norfenfluramine (dNF) in rhesus monkey brain. The accuracy of the MRS technique was assessed by comparison with gas chromatography. Brain 19F MRS signals were converted to brain DF + dNF concentrations after correction for signal relaxation losses and drug distribution in nonbrain tissue. Gas chromatography (GC) was used to assay brain DF and dNF concentrations following MRS evaluation. DF + dNF concentrations measured by 19F MRS averaged 104 +/- 36 microM (mean +/- SD) and GC measurements averaged 71 +/- 12 microM. Correction for the distribution of DF and its metabolites in nonbrain tissue yielded a DF + metabolite brain concentration that was within one standard deviation of the GC-derived value. The concentration of DF plus dNF measured by 19F MRS was similar to or greater than the value obtained by GC, which indicates that DF and its active metabolite dNF are fully detected by 19F MRS in primate brain in vivo. The application of these techniques to human subjects should enable the measurement of low micromolar-range brain concentrations of DF and other fluorinated drugs.
Collapse
Affiliation(s)
- J D Christensen
- Brain Imaging Center, McLean Hospital, Belmont, Massachusetts, USA
| | | | | | | |
Collapse
|
25
|
Abstract
OBJECTIVE To review recent developments in the pharmacotherapy of obesity, including the agents currently approved for use in the management of obesity and those under development. DATA SOURCES A MEDLINE search from January 1990 to July 1997 was conducted to identify English literature available on the pharmacotherapy of obesity. The search was supplemented by a review of the bibliographies of identified literature. STUDY SELECTION All controlled and uncontrolled trials were reviewed. When available, double-blind, placebo-controlled trials were used preferentially. DATA EXTRACTION Agents were reviewed with regard to mechanism of action, clinical trial data regarding efficacy, adverse effects, pharmacokinetics, drug interactions, and contraindications where information was available. Study design, selected population, results, and adverse effect information were included. DATA SYNTHESIS The anorexiants currently available or under development for the management of obesity regulate food intake and satiety via the adrenergic and/or serotonergic pathways. Clinical trials have shown a 10-15% weight loss can typically be anticipated; however, little long-term safety and efficacy data are available. Adverse events tend to be mild and self-limiting, but serious adverse events can occur. Treatment options under development include thermogenic agents, digestive inhibitors, and analogs and antagonists of hormones that regulate food intake and satiety. CONCLUSIONS Several mechanisms to control weight are currently under investigation for the management of obesity. Since obesity is a chronic condition, further studies should be conducted to evaluate the long-term safety and efficacy of these agents and the role of combination therapy using different modalities.
Collapse
Affiliation(s)
- J Cerulli
- Division of Pharmacy Practice, Albany College of Pharmacy, NY 12208, USA
| | | | | |
Collapse
|
26
|
Scheen AJ. Drug treatment of non-insulin-dependent diabetes mellitus in the 1990s. Achievements and future developments. Drugs 1997; 54:355-68. [PMID: 9279500 DOI: 10.2165/00003495-199754030-00001] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Non-insulin-dependent diabetes mellitus (NIDDM, type 2 diabetes) is a heterogeneous disease resulting from a dynamic interaction between defects in insulin secretion and insulin action. There are various pharmacological approaches to improving glucose homeostasis, but those currently used in clinical practice either do not succeed in restoring normoglycaemia in most patients or fail after a variable period of time. For glycaemic regulation, 4 classes of drugs are currently available: sulphonylureas, biguanides (metformin), alpha-glucosidase inhibitors (acarbose) and insulin, each of which has a different mode and site of action. These standard pharmacological treatments may be used individually for certain types of patients, or may be combined in a stepwise fashion to provide more ideal glycaemic control for most patients. Adjunct treatments comprise a few pharmacological approaches which may help to improve glycaemic control by correcting some abnormalities frequently associated with NIDDM, such as obesity (serotoninergic anorectic agents) and hyperlipidaemia (benfluorex). There is intensive pharmaceutical research to find new drugs able to stimulate insulin secretion (new sulphonylurea or nonsulphonylurea derivatives, glucagon-like peptide-1), improve insulin action (thiazolidinediones, lipid interfering agents, glucagon antagonists, vanadium compounds) or reduce carbohydrate absorption (miglitol, amylin analogues, glucagon-like peptide-1). Further studies should demonstrate the superiority of these new compounds over the standard antidiabetic agents as well as their optimal mode of administration, alone or in combination with currently available drugs.
Collapse
Affiliation(s)
- A J Scheen
- Department of Medicine, CHU Sart Tilman, Liège, Belgium
| |
Collapse
|
27
|
Abstract
Patients over age 40 should be made aware of the triad of risk factors for the disease and taught to recognize common signs and symptoms. Those with high-risk profiles should be tested regularly and counseled regarding preventive and therapeutic strategies. For obese patients whose weight cannot be brought under control with diet and exercise alone, a trial of anorectic agents should be considered.
Collapse
Affiliation(s)
- A E Kitabchi
- Division of Endocrinology and Metabolism, University of Tennessee College of Medicine, Memphis, USA
| | | |
Collapse
|
28
|
Curzon G, Gibson EL, Oluyomi AO. Appetite suppression by commonly used drugs depends on 5-HT receptors but not on 5-HT availability. Trends Pharmacol Sci 1997; 18:21-5. [PMID: 9114726 DOI: 10.1016/s0165-6147(96)01003-6] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The widely prescribed appetite suppressants D-fenfluramine and fluoxetine not only decrease feeding and body weight but also increase extracellular brain 5-HT. As central injection of 5-HT also decreases feeding, the drugs are often thought to require an increase of 5-HT at receptors in order to exert their hypophagic effect. However, much evidence now suggests that D-fenfluramine and its metabolite D-norfenfluramine can cause hypophagia by acting directly at unspecified 5-HT receptors and at 5-HT2C receptors, respectively, while fluoxetine may act independently of 5-HT receptors. These hypophagias may involve interference with the hyperphagic action of neuropeptide Y.
Collapse
Affiliation(s)
- G Curzon
- Institute of Neurology, London, UK
| | | | | |
Collapse
|