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Vestergaard ET, Zubanovic NB, Rittig N, Møller N, Kuhre RE, Holst JJ, Rehfeld JF, Thomsen HH. Acute ketosis inhibits appetite and decreases plasma concentrations of acyl ghrelin in healthy young men. Diabetes Obes Metab 2021; 23:1834-1842. [PMID: 33852195 DOI: 10.1111/dom.14402] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/31/2021] [Accepted: 04/08/2021] [Indexed: 12/27/2022]
Abstract
AIM To investigate the acute effect of ketone ester (KE) ingestion on appetite and plasma concentrations of acyl ghrelin (AG), unacylated ghrelin (UAG) and glucagon-like peptide-1 (GLP-1) secretion, and to compare responses with those elicited by isocaloric glucose (GLU) administration. METHODS We examined 10 healthy young men on three separate occasions using a placebo (PBO)-controlled crossover design. A KE versus taste-matched isovolumetric and isocaloric 50% GLU and taste-matched isovolumetric PBO vehicle was orally administered. Our main outcome measures were plasma concentrations of AG, UAG, glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 along with appetite sensation scores assessed by visual analogue scale. RESULTS KE ingestion resulted in an average peak beta-hydroxybutyrate concentration of 5.5 mM. AG and UAG were lowered by approximately 25% following both KE and GLU intake compared with PBO. In the case of AG, the differences were -52.1 (-79.4, -24.8) for KE and -48.4 (-75.4, -21.5) pg/mL for GLU intake (P < .01). Concentrations of AG remained lower with KE but returned to baseline and were comparable with PBO levels after GLU intake. GLP-1, GIP, gastrin and cholecystokinin were not affected by KE ingestion. CONCLUSION Our results suggest that the suppressive effects on appetite sensation scores associated with hyperketonaemia are more probable to be mediated through reduced ghrelin concentrations than by increased activity of cholecystokinin, gastrin, GIP or GLP-1.
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Affiliation(s)
- Esben Thyssen Vestergaard
- Department of Paediatrics, Regional Hospital Randers, Randers, Denmark
- Steno Diabetes Center Aarhus (SDCA), Aarhus, Denmark
| | - Natasa Brkovic Zubanovic
- Department of Internal Medicine, Clinic for Diabetes and Endocrinology, Viborg Regional Hospital, Viborg, Denmark
- Department and Laboratory of Internal Medicine and Endocrinology, MEA, Aarhus University Hospital, Aarhus, Denmark
| | - Nikolaj Rittig
- Steno Diabetes Center Aarhus (SDCA), Aarhus, Denmark
- Department and Laboratory of Internal Medicine and Endocrinology, MEA, Aarhus University Hospital, Aarhus, Denmark
| | - Niels Møller
- Department and Laboratory of Internal Medicine and Endocrinology, MEA, Aarhus University Hospital, Aarhus, Denmark
| | - Rune Ehrenreich Kuhre
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Obesity Pharmacology, Novo Nordisk, Måløv, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens F Rehfeld
- Department of Clinical Biochemistry (KB3011), Rigshospitalet, Copenhagen, Denmark
| | - Henrik Holm Thomsen
- Department of Internal Medicine, Clinic for Diabetes and Endocrinology, Viborg Regional Hospital, Viborg, Denmark
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Abstract
β-hydroxybutyrate, a ketone body metabolite, has been shown to suppress depression-like behavior in rodents. In this study, we examined its antidepressive property in acute and chronic administration modes in mice by using forced swim test and tail suspension test. Results showed that the decrease effect of β-hydroxybutyrate (300 mg/kg) on immobility time in the tail suspension test and forced swim test in stress-naive mice began to be significant at day 11. In a dose-dependent experiment, β-hydroxybutyrate treatment (11 days) showed significant antidepressant activities at the dose of 200 and 300 mg/kg. Unlike fluoxetine, β-hydroxybutyrate treatment (300 mg/kg) showed no antidepressant activities in the acute (1 hour before the test) and three times administration mode within 24 hours (1, 5, and 24 hours before the test). But in a co-administration mode, β-hydroxybutyrate (100 mg/kg) -fluoxetine (2.5 mg/kg) co-administration exhibited an obvious antidepressant activity in the tail suspension test and forced swim test. Further analysis showed that the antidepressant effects of β-hydroxybutyrate and fluoxetine were not associated with the change in mouse locomotor activity. Furthermore, both chronic β-hydroxybutyrate treatment and β-hydroxybutyrate-fluoxetine co-treatment suppressed chronic unpredictable stress-induced increase in immobility time in the tail suspension test and forced swim test as well as chronic unpredictable stress-induced decrease in mouse body weight. Taken together, these results indicate that β-hydroxybutyrate (1) needs a relatively long time to show comparable behavioral activity to that of fluoxetine in assays that are sensitive to the behavioral effects of established antidepressant compounds and (2) can augment the antidepressant action of a sub-therapeutic dose of fluoxetine.
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Seoane-Collazo P, Diéguez C, Nogueiras R, Rahmouni K, Fernández-Real JM, López M. Nicotine' actions on energy balance: Friend or foe? Pharmacol Ther 2020; 219:107693. [PMID: 32987056 DOI: 10.1016/j.pharmthera.2020.107693] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/21/2020] [Indexed: 12/12/2022]
Abstract
Obesity has reached pandemic proportions and is associated with severe comorbidities, such as type 2 diabetes mellitus, hepatic and cardiovascular diseases, and certain cancer types. However, the therapeutic options to treat obesity are limited. Extensive epidemiological studies have shown a strong relationship between smoking and body weight, with non-smokers weighing more than smokers at any age. Increased body weight after smoking cessation is a major factor that interferes with their attempts to quit smoking. Numerous controlled studies in both humans and rodents have reported that nicotine, the main bioactive component of tobacco, exerts a marked anorectic action. Furthermore, nicotine is also known to modulate energy expenditure, by regulating the thermogenic activity of brown adipose tissue (BAT) and the browning of white adipose tissue (WAT), as well as glucose homeostasis. Many of these actions occur at central level, by controlling the activity of hypothalamic neuropeptide systems such as proopiomelanocortin (POMC), or energy sensors such as AMP-activated protein kinase (AMPK). However, direct impact of nicotine on metabolic tissues, such as BAT, WAT, liver and pancreas has also been described. Here, we review the actions of nicotine on energy balance. The relevance of this interaction is interesting, because considering the restricted efficiency of obesity treatments, a possible complementary approach may focus on compounds with known pharmacokinetic profile and pharmacological actions, such as nicotine or nicotinic acetylcholine receptors signaling.
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Affiliation(s)
- Patricia Seoane-Collazo
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine and Veterans Affairs Health Care System, Iowa City, IA 52242, USA
| | - José Manuel Fernández-Real
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Department of Diabetes, Endocrinology and Nutrition (UDEN), Hospital of Girona "Dr Josep Trueta" and Department of Medical Sciences, Faculty of Medicine, University of Girona, Girona, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain.
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4
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González-García I, Milbank E, Martinez-Ordoñez A, Diéguez C, López M, Contreras C. HYPOTHesizing about central comBAT against obesity. J Physiol Biochem 2019; 76:193-211. [PMID: 31845114 DOI: 10.1007/s13105-019-00719-y] [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: 05/16/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022]
Abstract
The hypothalamus is a brain region in charge of many vital functions. Among them, BAT thermogenesis represents an essential physiological function to maintain body temperature. In the metabolic context, it has now been established that energy expenditure attributed to BAT function can contribute to the energy balance in a substantial extent. Thus, therapeutic interest in this regard has increased in the last years and some studies have shown that BAT function in humans can make a real contribution to improve diabetes and obesity-associated diseases. Nevertheless, how the hypothalamus controls BAT activity is still not fully understood. Despite the fact that much has been known about the mechanisms that regulate BAT activity in recent years, and that the central regulation of thermogenesis offers a very promising target, many questions remain still unsolved. Among them, the possible human application of knowledge obtained from rodent studies, and drug administration strategies able to specifically target the hypothalamus. Here, we review the current knowledge of homeostatic regulation of BAT, including the molecular insights of brown adipocytes, its central control, and its implication in the development of obesity.
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Affiliation(s)
- Ismael González-García
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.
| | - Edward Milbank
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Anxo Martinez-Ordoñez
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
| | - Carlos Diéguez
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Miguel López
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Cristina Contreras
- Department of Physiology, Pharmacy School, Complutense University of Madrid, 28040, Madrid, Spain.
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5
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Contreras C, Nogueiras R, Diéguez C, Rahmouni K, López M. Traveling from the hypothalamus to the adipose tissue: The thermogenic pathway. Redox Biol 2017; 12:854-863. [PMID: 28448947 PMCID: PMC5406580 DOI: 10.1016/j.redox.2017.04.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/08/2017] [Accepted: 04/11/2017] [Indexed: 01/13/2023] Open
Abstract
Brown adipose tissue (BAT) is a specialized tissue critical for non-shivering thermogenesis producing heat through mitochondrial uncoupling; whereas white adipose tissue (WAT) is responsible of energy storage in the form of triglycerides. Another type of fat has been described, the beige adipose tissue; this tissue emerges in existing WAT depots but with thermogenic ability, a phenomenon known as browning. Several peripheral signals relaying information about energy status act in the brain, particularly the hypothalamus, to regulate thermogenesis in BAT and browning of WAT. Different hypothalamic areas have the capacity to regulate the thermogenic process in brown and beige adipocytes through the sympathetic nervous system (SNS). This review discusses important concepts and discoveries about the central control of thermogenesis as a trip that starts in the hypothalamus, and taking the sympathetic roads to reach brown and beige fat to modulate thermogenic functions.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain.
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain.
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6
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Koch K, Berressem D, Konietzka J, Thinnes A, Eckert GP, Klein J. Hepatic Ketogenesis Induced by Middle Cerebral Artery Occlusion in Mice. J Am Heart Assoc 2017; 6:JAHA.117.005556. [PMID: 28381467 PMCID: PMC5533036 DOI: 10.1161/jaha.117.005556] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Ketone bodies are known to substitute for glucose as brain fuel when glucose availability is low. Ketogenic diets have been described as neuroprotective. Similar data have been reported for triheptanoin, a fatty oil and anaplerotic compound. In this study, we monitored the changes of energy metabolites in liver, blood, and brain after transient brain ischemia to test for ketone body formation induced by experimental stroke. Methods and Results Mice were fed a standard carbohydrate‐rich diet or 2 fat‐rich diets, 1 enriched in triheptanoin and 1 in soybean oil. Stroke was induced in mice by middle cerebral artery occlusion for 90 minutes, followed by reperfusion. Mice were sacrificed, and blood plasma and liver and brain homogenates were obtained. In 1 experiment, microdialysis was performed. Metabolites (eg glucose, β‐hydroxybutyrate, citrate, succinate) were determined by gas chromatography–mass spectrometry. After 90 minutes of brain ischemia, β‐hydroxybutyrate levels were dramatically increased in liver, blood, and brain microdialysate and brain homogenate, but only in mice fed fat‐rich diets. Glucose levels were changed in the opposite manner in blood and brain. Reperfusion decreased β‐hydroxybutyrate and increased glucose within 60 minutes. Stroke‐induced ketogenesis was blocked by propranolol, a β‐receptor antagonist. Citrate and succinate were moderately increased by fat‐rich diets and unchanged after stroke. Conclusions We conclude that brain ischemia induces the formation of β‐hydroxybutyrate (ketogenesis) in the liver and the consumption of β‐hydroxybutyrate in the brain. This effect seems to be mediated by β‐adrenergic receptors.
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Affiliation(s)
- Konrad Koch
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
| | - Dirk Berressem
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
| | - Jan Konietzka
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
| | - Anna Thinnes
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
| | - Gunter P Eckert
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
| | - Jochen Klein
- Department of Pharmacology, FB 14, Goethe University, Frankfurt, Germany
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7
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López M, Tena-Sempere M. Estradiol effects on hypothalamic AMPK and BAT thermogenesis: A gateway for obesity treatment? Pharmacol Ther 2017; 178:109-122. [PMID: 28351720 DOI: 10.1016/j.pharmthera.2017.03.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/21/2017] [Indexed: 12/24/2022]
Abstract
In addition to their prominent roles in the control of reproduction, estrogens are important modulators of energy balance, as evident in conditions of deficiency of estrogens, which are characterized by increased feeding and decreased energy expenditure, leading to obesity. AMP-activated protein kinase (AMPK) is a ubiquitous cellular energy gauge that is activated under conditions of low energy, increasing energy production and reducing energy wasting. Centrally, the AMPK pathway is a canonical route regulating energy homeostasis, by integrating peripheral signals, such as hormones and metabolites, with neuronal networks. As a result of those actions, hypothalamic AMPK modulates feeding, as well as brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT). Here, we will review the central actions of estrogens on energy balance, with particular focus on hypothalamic AMPK. The relevance of this interaction is noteworthy, because some agents with known actions on metabolic homeostasis, such as nicotine, metformin, liraglutide, olanzapine and also natural molecules, such as resveratrol and flavonoids, exert their actions by modulating AMPK. This evidence highlights the possibility that hypothalamic AMPK might be a potential target for the treatment of obesity.
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Affiliation(s)
- Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), 15782 Santiago de Compostela, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos II, Spain.
| | - Manuel Tena-Sempere
- CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos II, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Spain; Instituto Maimónides de Investigación Biomédica (IMIBIC)/Hospital Reina Sofía, 14004 Córdoba, Spain; FiDiPro Program, Department of Physiology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.
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8
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Contreras C, Nogueiras R, Diéguez C, Medina-Gómez G, López M. Hypothalamus and thermogenesis: Heating the BAT, browning the WAT. Mol Cell Endocrinol 2016; 438:107-115. [PMID: 27498420 DOI: 10.1016/j.mce.2016.08.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/30/2016] [Accepted: 08/01/2016] [Indexed: 12/20/2022]
Abstract
Brown adipose tissue (BAT) has been also considered as the main thermogenic organ responsible of maintenance body temperature through heat production. However, a new type of thermogenic fat has been characterized during the last years, the beige or brite fat, that is developed from white adipose tissue (WAT) in response to different stimuli by a process known as browning. The activities of brown and beige adipocytes ameliorate metabolic disease, including obesity in mice and correlate with leanness in humans. Many genes and pathways that regulate brown and beige adipocyte biology have now been identified, providing a variety of promising therapeutic targets for metabolic disease. The hypothalamus is the main central place orchestrating the outflow signals that drive the sympathetic nerve activity to BAT and WAT, controlling heat production and energy homeostasis. Recent data have revealed new hypothalamic molecular mechanisms, such as hypothalamic AMP-activated protein kinase (AMPK), that control both thermogenesis and browning. This review provides an overview of the factors influencing BAT and WAT thermogenesis, with special focus on the integration of peripheral information on hypothalamic circuits controlling thermoregulation.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain.
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, 28922, Alcorcón, Madrid, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain.
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9
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Seoane-Collazo P, Fernø J, Gonzalez F, Diéguez C, Leis R, Nogueiras R, López M. Hypothalamic-autonomic control of energy homeostasis. Endocrine 2015; 50:276-91. [PMID: 26089260 DOI: 10.1007/s12020-015-0658-y] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 06/06/2015] [Indexed: 10/23/2022]
Abstract
Regulation of energy homeostasis is tightly controlled by the central nervous system (CNS). Several key areas such as the hypothalamus and brainstem receive and integrate signals conveying energy status from the periphery, such as leptin, thyroid hormones, and insulin, ultimately leading to modulation of food intake, energy expenditure (EE), and peripheral metabolism. The autonomic nervous system (ANS) plays a key role in the response to such signals, innervating peripheral metabolic tissues, including brown and white adipose tissue (BAT and WAT), liver, pancreas, and skeletal muscle. The ANS consists of two parts, the sympathetic and parasympathetic nervous systems (SNS and PSNS). The SNS regulates BAT thermogenesis and EE, controlled by central areas such as the preoptic area (POA) and the ventromedial, dorsomedial, and arcuate hypothalamic nuclei (VMH, DMH, and ARC). The SNS also regulates lipid metabolism in WAT, controlled by the lateral hypothalamic area (LHA), VMH, and ARC. Control of hepatic glucose production and pancreatic insulin secretion also involves the LHA, VMH, and ARC as well as the dorsal vagal complex (DVC), via splanchnic sympathetic and the vagal parasympathetic nerves. Muscle glucose uptake is also controlled by the SNS via hypothalamic nuclei such as the VMH. There is recent evidence of novel pathways connecting the CNS and ANS. These include the hypothalamic AMP-activated protein kinase-SNS-BAT axis which has been demonstrated to be a key modulator of thermogenesis. In this review, we summarize current knowledge of the role of the ANS in the modulation of energy balance.
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Affiliation(s)
- Patricia Seoane-Collazo
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain.
| | - Johan Fernø
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- Department of Clinical Science, K. G. Jebsen Center for Diabetes Research, University of Bergen, 5021, Bergen, Norway
| | - Francisco Gonzalez
- Department of Surgery, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- Service of Ophthalmology, Complejo Hospitalario Universitario de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Carlos Diéguez
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Rosaura Leis
- Unit of Investigation in Nutrition, Growth and Human Development of Galicia, Pediatric Department (USC), Complexo Hospitalario Universitario de Santiago (IDIS/SERGAS), Santiago de Compostela, Spain
| | - Rubén Nogueiras
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain.
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10
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Morrison SF, Madden CJ. Central nervous system regulation of brown adipose tissue. Compr Physiol 2015; 4:1677-713. [PMID: 25428857 DOI: 10.1002/cphy.c140013] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thermogenesis, the production of heat energy, in brown adipose tissue is a significant component of the homeostatic repertoire to maintain body temperature during the challenge of low environmental temperature in many species from mouse to man and plays a key role in elevating body temperature during the febrile response to infection. The sympathetic neural outflow determining brown adipose tissue (BAT) thermogenesis is regulated by neural networks in the CNS which increase BAT sympathetic nerve activity in response to cutaneous and deep body thermoreceptor signals. Many behavioral states, including wakefulness, immunologic responses, and stress, are characterized by elevations in core body temperature to which central command-driven BAT activation makes a significant contribution. Since energy consumption during BAT thermogenesis involves oxidation of lipid and glucose fuel molecules, the CNS network driving cold-defensive and behavioral state-related BAT activation is strongly influenced by signals reflecting the short- and long-term availability of the fuel molecules essential for BAT metabolism and, in turn, the regulation of BAT thermogenesis in response to metabolic signals can contribute to energy balance, regulation of body adipose stores and glucose utilization. This review summarizes our understanding of the functional organization and neurochemical influences within the CNS networks that modulate the level of BAT sympathetic nerve activity to produce the thermoregulatory and metabolic alterations in BAT thermogenesis and BAT energy expenditure that contribute to overall energy homeostasis and the autonomic support of behavior.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon
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11
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Contreras C, Gonzalez F, Fernø J, Diéguez C, Rahmouni K, Nogueiras R, López M. The brain and brown fat. Ann Med 2015; 47:150-68. [PMID: 24915455 PMCID: PMC4438385 DOI: 10.3109/07853890.2014.919727] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 04/25/2014] [Indexed: 02/06/2023] Open
Abstract
Brown adipose tissue (BAT) is a specialized organ responsible for thermogenesis, a process required for maintaining body temperature. BAT is regulated by the sympathetic nervous system (SNS), which activates lipolysis and mitochondrial uncoupling in brown adipocytes. For many years, BAT was considered to be important only in small mammals and newborn humans, but recent data have shown that BAT is also functional in adult humans. On the basis of this evidence, extensive research has been focused on BAT function, where new molecules, such as irisin and bone morphogenetic proteins, particularly BMP7 and BMP8B, as well as novel central factors and new regulatory mechanisms, such as orexins and the canonical ventomedial nucleus of the hypothalamus (VMH) AMP- activated protein kinase (AMPK)-SNS-BAT axis, have been discovered and emerged as potential drug targets to combat obesity. In this review we provide an overview of the complex central regulation of BAT and how different neuronal cell populations co-ordinately work to maintain energy homeostasis.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria , Santiago de Compostela, 15782 , Spain
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12
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Morrison SF, Madden CJ, Tupone D. Central neural regulation of brown adipose tissue thermogenesis and energy expenditure. Cell Metab 2014; 19:741-756. [PMID: 24630813 PMCID: PMC4016184 DOI: 10.1016/j.cmet.2014.02.007] [Citation(s) in RCA: 312] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thermogenesis, the production of heat energy, is the specific, neurally regulated, metabolic function of brown adipose tissue (BAT) and contributes to the maintenance of body temperature during cold exposure and to the elevated core temperature during several behavioral states, including wakefulness, the acute phase response (fever), and stress. BAT energy expenditure requires metabolic fuel availability and contributes to energy balance. This review summarizes the functional organization and neurochemical influences within the CNS networks governing the level of BAT sympathetic nerve activity to produce the thermoregulatory and metabolically driven alterations in BAT thermogenesis and energy expenditure that contribute to overall energy homeostasis.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery Oregon Health & Science University Portland, OR, 97239 USA
| | - Christopher J Madden
- Department of Neurological Surgery Oregon Health & Science University Portland, OR, 97239 USA
| | - Domenico Tupone
- Department of Neurological Surgery Oregon Health & Science University Portland, OR, 97239 USA
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13
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Role of beta-hydroxybutyric acid in the central regulation of energy balance. Appetite 2010; 54:450-5. [PMID: 20416348 DOI: 10.1016/j.appet.2010.04.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 04/12/2010] [Accepted: 04/15/2010] [Indexed: 01/11/2023]
Abstract
Although the phenomenon of beta-hydroxybutyric acid (BHBA) impact on satiety and thermogenesis has been described in the past decades, the underlying molecular mechanisms involved remain unresolved. Other metabolites such as glucose, fatty or branched chain amino acids are known to activate the AMP kinase pathway leading to an increase of anorexic and a decrease of orexigenic neuropeptides in the hypothalamus, one of the central regulators of energy homeostasis. Since BHBA is utilized as an energy source by the brain particularly in suckling newborns and under starving conditions, it is supposed to be a further central signal and energy providing substrate involved in the regulation of food intake. Moreover, BHBA might present a therapeutic approach for treating neuronal diseases because of its neuroprotective properties. Therefore, the purpose of this review is to summarize the known central effects of BHBA and to point out the importance of the identification of cellular pathways triggered in response to BHBA.
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Raffo E, François J, Ferrandon A, Koning E, Nehlig A. Calorie-restricted ketogenic diet increases thresholds to all patterns of pentylenetetrazol-induced seizures: Critical importance of electroclinical assessment. Epilepsia 2008; 49:320-8. [DOI: 10.1111/j.1528-1167.2007.01380.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Bray GA, York DA. Obesity. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bough KJ, Matthews PJ, Eagles DA. A ketogenic diet has different effects upon seizures induced by maximal electroshock and by pentylenetetrazole infusion. Epilepsy Res 2000; 38:105-14. [PMID: 10642038 DOI: 10.1016/s0920-1211(99)00079-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of these experiments was to determine whether a ketogenic diet previously shown to elevate seizure threshold also reduced seizure severity. Seizure threshold was tested by intravenous infusion of pentylenetetrazole (PTZ) whereas seizure severity was determined from measuring the hindlimb extension to flexion (E/F) ratio after seizures were evoked by maximal electroshock stimulation (MES). Surprisingly, seizures evoked by MES were more severe in animals fed a calorie-restricted ketogenic diet. Controls fed an isocaloric, calorie-restricted normal diet also exhibited more severe seizures than did animals fed the same diet ad libitum. When seizure threshold was evaluated in the same animals, those animals fed a calorie-restricted ketogenic diet exhibited a significant increase in seizure resistance compared to animals fed a ketogenic diet ad libitum, a calorie-restricted normal diet or a normal diet ad libitum. These findings suggest that both the amount and type of food affect seizures in rats and show that diet-related seizure protection depends upon the method by which seizures are provoked.
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Affiliation(s)
- K J Bough
- Department of Biology, Georgetown University, Washington, DC 20057-1229, USA
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17
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Bough KJ, Yao SG, Eagles DA. Higher ketogenic diet ratios confer protection from seizures without neurotoxicity. Epilepsy Res 2000; 38:15-25. [PMID: 10604602 DOI: 10.1016/s0920-1211(99)00077-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study was designed to establish a dose-response relationship for the efficacy of the ketogenic diet (KD). Sprague-Dawley rats were fed ketogenic diets containing varying ratios of fats; (carbohydrates + proteins) whereas control animals were fed rodent chow. Unless otherwise indicated, all animals were fed calorie-restricted, isocaloric diets beginning at P37 and ketonemia, seizure threshold and neurotoxic effects were determined. Despite being provided isocaloric quantities, animals fed lower ketogenic ratios gained weight relative to those fed diets having greater proportions of fats. A significantly increased metabolic rate was noted for animals fed a high-fat diet, suggesting a basis for the weight differences. Results also showed that the animals fed calorie-restricted high-fat diets exhibited significant ketonemia and protection from pentylenetetrazole (PTZ)-induced seizures. There were no detectable neurotoxic effects for any diet group. For animals of the same age, there was no correlation between beta-hydroxybutyrate (beta-OHB) and seizure threshold. These findings suggest that beta-OHB is not directly involved in the anticonvulsant mechanism of the diet. Also, data presented here show that the conventional 4:1 ketogenic diet does not confer the greatest level of seizure protection. We conclude that a 6:1 ketogenic diet, which shows no evidence of neurotoxicity, may be maximally efficacious in rats.
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Affiliation(s)
- K J Bough
- Department of Biology, Georgetown University, Washington, DC 20057-1229, USA
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Affiliation(s)
- G A Bray
- Louisiana State University, Pennington Biomedical Research Center, Baton Rouge 70808-4124, USA
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19
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Abstract
Fatty acid oxidation seems to provide an important stimulus for metabolic control of food intake, because various inhibitors of fatty acid oxidation (mercaptoacetate, methyl palmoxirate, R-3-amino-4-trimethylaminobutyric acid) stimulated feeding in rats and/or mice, in particular when fed a fat-enriched diet, and long-term intravascular infusion of lipids reduced voluntary food intake in various species, including humans. The feeding response to decreased fatty acid oxidation was due to a shortening of the intermeal interval with meal size remaining unaffected. Thus, energy derived from fatty acid oxidation seems to contribute to control of the duration of postmeal satiety and meal onset. Since inhibition of glucose metabolism by 2-deoxy-D-glucose affects feeding pattern similarly, and spontaneous meals were shown to be preceded by a transient decline in blood glucose in rats and humans, a decrease in energy availability from glucose and fatty acid oxidation seems to be instrumental in eliciting eating. Since the feeding response of rats to inhibition of fatty acid oxidation was abolished by total abdominal vagotomy and pretreatment with capsaicin destroying non-myelinated afferents and attenuated by hepatic branch vagotomy, fatty acid oxidation in abdominal tissues, especially in the liver, apparently is signalled to the brain by vagal afferents to affect eating. Brain lesions and Fos immunohistochemistry were employed to identify pathways within the brain mediating eating in response to decreased fatty acid oxidation. According to these studies, the nucleus tractus solitarii (NTS) of the medulla oblongata represents the gate for central processing of vagally mediated afferent information related to fatty acid oxidation. The lateral parabrachial nucleus of the pons seems to be a major relay for pertinent ascending input from the NTS. In particular the central nucleus of the amygdala, a projection area of the parabrachial nucleus, appears to be crucial for eating in response to decreased fatty acid oxidation. As ketones are products of hepatic fatty acid oxidation that are released into the circulation and peripheral (and central) administration of 3-hydroxybutyrate reduced voluntary food intake in rats, ketones being utilized as fuels by the peripheral and central nervous system might contribute to control of eating by fatty acid oxidation, especially when high levels of circulating ketones occur. Whether a modulation of the hepatic membrane potential resulting from changes in the rate of fatty acid oxidation and/or ketogenesis represent a signal for control of eating transmitted to the brain by vagal afferents remains to be established. Recent in vivo studies investigating the effects of mercaptoacetate on the hepatic membrane potential and on afferent activity of the hepatic vagus branch are consistent with this notion. Further investigations are necessary to delineate the coding mechanisms by which fatty acid oxidation and/or ketogenesis modulate vagal afferent activity.
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Affiliation(s)
- E Scharrer
- Institute of Veterinary Physiology, University of Zurich, Switzerland.
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Liverini G, Iossa S, Mollica MP, Lionetti L, Barletta A. Hepatic fatty acid-supported respiration in rats fed an energy-dense diet. Cell Biochem Funct 1996; 14:283-9. [PMID: 8952047 DOI: 10.1002/cbf.692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The energy balance and hepatic fatty acid-supported respiration were studied in rats fed a control or an energy-dense diet. In addition, state 3 and 4 respiratory rates as well as ketone body production with palmitoylcarnitine as substrate were determined in isolated mitochondria. Metabolizable energy intake and energy expenditure increased in rats fed an energy-dense diet, but the gain in body weight and lipid content remained unchanged. No variation occurred in the mitochondrial palmitoylcarnitine utilization rate and ketone body production, but a significant increase in the mitochondrial content of ketone bodies and the serum levels was found in rats fed an energy-dense diet. Furthermore, we have shown a significant increase in fatty acid-stimulated respiration in hepatocytes from rats fed an energy-dense diet. The enhanced hepatic fatty acid utilization as an energy substrate found in rats fed an energy-dense diet may contribute to reduce the availability of lipids for storage, thus counteracting the development of obesity.
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Affiliation(s)
- G Liverini
- Department of General and Environmental Physiology, University of Naples, Italy.
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21
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Hirasawa M, Nishihara M, Takahashi M. Neural activity in the VMH associated with suppression of the circulatory system in rats. Physiol Behav 1996; 59:1017-23. [PMID: 8737888 DOI: 10.1016/0031-9384(95)02223-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Spontaneous neural activity within the ventromedial nucleus of the hypothalamus (VMH) was monitored in rats to search for neurons regulating the autonomic nervous system. By means of multiple unit activity (MUA) recording method, unique explosive rises in neural activity (MUA volleys), 1 to 4 min in duration, were recorded in conscious freely moving animals. Heart rate was monitored as an autonomic parameter and found to decrease when MUA volleys appeared. These MUA volleys also occurred under urethane anesthesia, and blood pressure and heart rate decreased simultaneously with the volleys, but body temperature remained constant. This fall in blood pressure (but not heart rate) was replicated by electrical stimulation through the electrodes that recorded MUA volleys, suggesting that the neurons responsible for MUA volleys can suppress the circulatory system. The frequency of MUA volleys exhibited a clear diurnal variation: they appeared every 15 or 30 min in the light phase but only seldom in the dark. This diurnal variation seems to be an endogenous circadian rhythm because it was indicated to freerun after blinding the animals. These results suggest that there is a discrete population of neurons in the VMH that fires predominantly during the light phase in an episodic manner and suppresses the circulatory system.
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Affiliation(s)
- M Hirasawa
- Department of Veterinary Physiology, University of Tokyo, Japan
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22
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Nagase H, Bray GA, York DA. Effects of pyruvate and lactate on food intake in rat strains sensitive and resistant to dietary obesity. Physiol Behav 1996; 59:555-60. [PMID: 8700960 DOI: 10.1016/0031-9384(95)02109-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have investigated the effects of peripherally administered pyruvate and lactate on the intake of high fat (HF) and low fat (LF) diets by a strain of rat either sensitive (Osborne-Mendel, OM) or resistant (SSB/Pl) to high fat-induced obesity. Both pyruvate and lactate inhibited the intake of HF and LF diets by OM rats and these effects were blocked by selective hepatic vagotomy. In contrast, in S5B/Pl rats fed an LF diet the responses to pyruvate and lactate were attenuated and were absent in S5B/Pl rats fed the HF diet. These data suggest that OM and S5B/Pl rats differ either in their metabolism of pyruvate and lactate or in their responses to these metabolites.
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Affiliation(s)
- H Nagase
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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23
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Abstract
This article discusses the role of the lateral hypothalamic area (LHA) in feeding and drinking and draws on data obtained from lesion and stimulation studies and neurochemical and electrophysiological manipulations of the area. The LHA is involved in catecholaminergic and serotonergic feeding systems and plays a role in circadian feeding, sex differences in feeding and spontaneous activity. This article discusses the LHA regarding dietary self-selection, responses to high-protein diets, amino acid imbalances, liquid and cafeteria diets, placentophagia, "stress eating," finickiness, diet texture, consistency and taste, aversion learning, olfaction and the effects of post-operative period manipulations by hormonal and other means. Glucose-sensitive neurons have been identified in the LHA and their manipulation by insulin and 2-deoxy-D-glucose is discussed. The effects on feeding of numerous transmitters, hormones and appetite depressants are described, as is the role of the LHA in salivation, lacrimation, gastric motility and secretion, and sensorimotor deficits. The LHA is also illuminated as regards temperature and feeding, circumventricular organs and thirst and electrolyte dynamics. A discussion of its role in the ischymetric hypothesis as an integrative Gestalt concept concludes the review.
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Affiliation(s)
- L L Bernardis
- Neurovisceral-Neuroendocrine Laboratory, Veterans Administration Medical Center Buffalo, NY, USA
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Sakaguchi T, Sandoh N, Aono T. Glucose signal in the nucleus of the vagus nerve modulates the cyclicity of gastric motility in rats. Brain Res 1994; 641:163-6. [PMID: 8019844 DOI: 10.1016/0006-8993(94)91832-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cyclicity and intensity of gastric motility were examined following glucose injection into the nucleus of the vagus nerve (X) or into the nucleus of the solitary tract (SOL) in anesthetized rats. Enhanced gastric motility caused by insulin administration was influenced by 4 mM glucose (500 nl) injected into the X; glucose provoked a shift in the cyclicity power spectrum without any change in intensity. The peak power spectrum shifted from 4.0-5.0 cpm to 2.0-3.0 cpm, but not significant change in the cyclicity power spectrum was seen when the same dose of glucose was injected into the SOL. It was also noted that the power spectrum response to 4 mM glucose injection into the X was not modified when 4 mM glucose was injected into the SOL simultaneously. The results suggest that the medullary glucose signal in the X differentially modulates the cyclicity of gastric motility independent of the SOL.
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Affiliation(s)
- T Sakaguchi
- Department of Physiology, Niigata University School of Medicine, Japan
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25
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Kolanowski J, Young JB, Landsberg L. Stimulatory influence of D(-)3-hydroxybutyrate feeding on sympathetic nervous system activity in the rat. Metabolism 1994; 43:180-5. [PMID: 8121299 DOI: 10.1016/0026-0495(94)90242-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To examine the effect of ketone body utilization on sympathetic nervous system (SNS) activity, norepinephrine (NE) turnover was measured in heart and interscapular brown adipose tissue (IBAT) of rats fed diets enriched with D(-)3-hydroxybutyrate (3OHB), the naturally occurring isomer of hydroxybutyrate. Isoenergetic substitution of 3OHB for chow for 4 days increased cardiac [3H]NE turnover (P < .025), with a slightly less marked (P < .06) effect in IBAT. When [3H]NE turnover was measured in rats fed chow diets supplemented with 3OHB or sucrose and compared with that in animals fed chow alone, [3H]NE turnover rates in heart and IBAT were similar in the ketone-supplemented and chow-fed groups. Animals fed the sucrose-supplemented chow displayed lower rates of [3H]NE turnover in IBAT than rates found in those given the 3OHB-containing chow (-36%, P < .025 in IBAT). In addition, the stimulatory effect on SNS activity of a 4-day exposure to a sucrose-enriched diet after 2 days of fasting was significantly enhanced by concomitant ketone ingestion. Fractional NE turnover in IBAT was increased from 9.3% +/- 1.3%/h in control rats to 14.2% +/- 0.9%/h in rats refed with 3OHB (P < .005). These observations indicate that increased ketone body utilization does not suppress SNS activity and may stimulate it in a manner quantitatively similar to that seen with carbohydrate or fat ingestion.
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Affiliation(s)
- J Kolanowski
- Department of Physiology, University of Louvain Medical School, Brussels, Belgium
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26
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Minami T, Shimizu N, Duan S, Oomura Y. Hypothalamic neuronal activity responses to 3-hydroxybutyric acid, an endogenous organic acid. Brain Res 1990; 509:351-4. [PMID: 2322832 DOI: 10.1016/0006-8993(90)90565-s] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To elucidate the anorectic action of the endogenous organic acid, 3-hydroxybutyric acid (3-HBA), its effects on neurons in both the rat ventromedial hypothalamic nucleus (VMH) and the lateral hypothalamic area (LHA) were examined. Iontophoretic application of 3-HBA significantly facilitated the firing rate of VMH neurons, whereas facilitation and inhibition were observed in the LHA. These responses were specific to the glucoreceptor neurons in the VMH and glucose-sensitive neurons in the LHA. Intracellular recordings from brain slice preparations revealed that 3-HBA depolarized the cell membrane of the VMH neuron with an associated increase of membrane input resistance. This was similar to the effect of glucose on glucoreceptor neurons in the VMH. These results suggest that 3-HBA may modulate hypothalamic chemosensitive neuron activity as well as function as an endogenous satiety factor.
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Affiliation(s)
- T Minami
- Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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27
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Sakaguchi T, Bray GA. Effect of norepinephrine, serotonin and tryptophan on the firing rate of sympathetic nerves. Brain Res 1989; 492:271-80. [PMID: 2752301 DOI: 10.1016/0006-8993(89)90910-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The firing rate of sympathetic nerves innervating interscapular brown adipose tissue (IBAT) has been recorded following microinjection of monoamines into the ventromedial (VMN) and paraventricular nuclei (PVN). Microinjection of norepinephrine (10 nmol) into the paraventricular nucleus produced a biphasic pattern in the firing rate of the sympathetic efferent nerves to IBAT. There was an initial dose-related 20% inhibition of firing rate followed 2 min later by 10% increase above control. When 10 times as much norepinephrine was injected into the ventromedial hypothalamus, there was a small 5% decrease in firing rate and a later significant dose-related increase in firing rate. These effects of norepinephrine were blocked by phentolamine, an alpha-adrenergic blocking drug, but not by propranolol, a beta-adrenergic blocking drug. Injection of serotonin into the paraventricular nucleus produced a short-lived but significant increase in firing rate of sympathetic nerves to brown adipose tissue. Comparable amounts of serotonin injected into the ventromedial nucleus produced a similar magnitude of increase in firing rate which lasted longer. There was a clear dose-response effect of serotonin injected into the PVN, but a much less impressive response when serotonin was injected into the VMN. The response to injections of tryptophan in both the VMN and PVN was similar to those seen with serotonin. When serotonin or tryptophan were injected into the PVN and VMN simultaneously, there was a synergistic increase in sympathetic firing rate. These data are consistent with the hypothesis that both norepinephrine and serotonin can modulate sympathetic firing rate through interaction with neurons in either the VMN or PVN.
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Affiliation(s)
- T Sakaguchi
- Department of Medicine, University of Southern California, School of Medicine, Los Angeles 90033
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Abstract
This article has examined the regulated systems that control nutrient balance. From this analysis, the following conclusions may be suggested: 1. Each nutrient is regulated separately in a feedback system. 2. The control of glucose is regulated by the size of the glycogen stores; the size of the fat depots, by the rate of hepatic fatty acid oxidation; and protein, by the size of the protein depots. 3. Obesity can occur as a result of hyperphagia or from repartitioning the deposition of nutrients. In either case, there is a relative or absolute reduction in the activity of the sympathetic nervous system, requiring adequate levels of circulating corticosteroids.
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Affiliation(s)
- G A Bray
- Section of Diabetes and Clinical Nutrition, University of Southern California, USC/LAC School of Medicine
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Affiliation(s)
- J Himms-Hagen
- Department of Biochemistry, University of Ottawa, Ontario, Canada
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