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Romano A, Friuli M, Cifani C, Gaetani S. Oxytocin in the neural control of eating: At the crossroad between homeostatic and non-homeostatic signals. Neuropharmacology 2020; 171:108082. [PMID: 32259527 DOI: 10.1016/j.neuropharm.2020.108082] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/10/2020] [Accepted: 03/30/2020] [Indexed: 12/21/2022]
Abstract
The understanding of the biological substrates regulating feeding behavior is relevant to address the health problems related to food overconsumption. Several studies have expanded the conventional view of the homeostatic regulation of body weight mainly orchestrated by the hypothalamus, to include also the non-homeostatic control of appetite. Such processes include food reward and are mainly coordinated by the activation of the central mesolimbic dopaminergic pathway. The identification of endogenous systems acting as a bridge between homoeostatic and non-homeostatic pathways might represent a significant step toward the development of drugs for the treatment of aberrant eating patterns. Oxytocin is a hypothalamic hormone that is directly secreted into the brain and reaches the blood circulation through the neurohypophysis. Oxytocin regulates a variety of physiologic functions, including eating and metabolism. In the last years both preclinical and clinical studies well characterized oxytocin for its effects in reducing food intake and body weight. In the present review we summarize the role played by oxytocin in the control of both homeostatic and non-homeostatic eating, within cognitive, metabolic and reward mechanisms, to mostly highlight its potential therapeutic effects as a new pharmacological approach for the development of drugs for eating disorders. We conclude that the central oxytocinergic system is possibly one of the mechanisms that coordinate energy balance at the crossroads between homeostatic and non-homeostatic mechanisms. This concept should foster studies aimed at exploring the possible exploitation of oxytocin in the treatment of aberrant eating patterns. This article is part of the special issue on Neuropeptides.
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Affiliation(s)
- Adele Romano
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Marzia Friuli
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032, Camerino, MC, Italy
| | - Silvana Gaetani
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy.
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Shi Z, Madden CJ, Brooks VL. Arcuate neuropeptide Y inhibits sympathetic nerve activity via multiple neuropathways. J Clin Invest 2017. [PMID: 28628036 PMCID: PMC5490747 DOI: 10.1172/jci92008] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Obesity increases sympathetic nerve activity (SNA) via activation of proopiomelanocortin neurons in the arcuate nucleus (ArcN), and this action requires simultaneous withdrawal of tonic neuropeptide Y (NPY) sympathoinhibition. However, the sites and neurocircuitry by which NPY decreases SNA are unclear. Here, using designer receptors exclusively activated by designer drugs (DREADDs) to selectively activate or inhibit ArcN NPY neurons expressing agouti-related peptide (AgRP) in mice, we have demonstrated that this neuronal population tonically suppresses splanchnic SNA (SSNA), arterial pressure, and heart rate via projections to the paraventricular nucleus (PVN) and dorsomedial hypothalamus (DMH). First, we found that ArcN NPY/AgRP fibers closely appose PVN and DMH presympathetic neurons. Second, nanoinjections of NPY or an NPY receptor Y1 (NPY1R) antagonist into PVN or DMH decreased or increased SSNA, respectively. Third, blockade of DMH NPY1R reversed the sympathoinhibition elicited by selective, DREADD-mediated activation of ArcN NPY/AgRP neurons. Finally, stimulation of ArcN NPY/AgRP terminal fields in the PVN and DMH decreased SSNA. Considering that chronic obesity decreases ArcN NPY content, we propose that the ArcN NPY neuropathway to the PVN and DMH is pivotal in obesity-induced elevations in SNA.
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Affiliation(s)
- Zhigang Shi
- Department of Physiology and Pharmacology and
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
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3
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Wang G, Williams CA, McConn BR, Cline MA, Gilbert ER. A high fat diet enhances the sensitivity of chick adipose tissue to the effects of centrally injected neuropeptide Y on gene expression of adipogenesis-associated factors. Comp Biochem Physiol A Mol Integr Physiol 2017. [PMID: 28625910 DOI: 10.1016/j.cbpa.2017.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of this study was to determine how dietary macronutrient composition and exogenous neuropeptide Y (NPY) affect mRNA abundance of factors associated with lipid metabolism in chick adipose tissue. Chicks were fed one of three isocaloric (3000kcal metabolizable energy (ME)/kg) diets after hatch: high carbohydrate (HC; control), high fat (HF; 30% of ME from soybean oil) or high protein (HP; 25% crude protein). On day 4 post-hatch, vehicle or 0.2nmol of NPY was injected intracerebroventricularly and abdominal and subcutaneous fat depots collected 1h later. In abdominal fat, mRNA abundance of peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid binding protein 4 (FABP4) increased after NPY injection in HF diet-fed chicks. NPY injection decreased expression of PPARγ and sterol regulatory element-binding transcription factor 1 (SREBP1) in the subcutaneous fat of HC diet-fed chicks, whereas SREBP1 expression was increased in the subcutaneous fat of HF diet-fed chicks after NPY injection. An acutely increased central concentration of NPY in chicks affects adipose tissue physiology in a depot- and diet-dependent manner. The chick may serve as a model to understand the relationship between diet and the brain-fat axis' role in maintaining whole body energy homeostasis, as well as to understand metabolic distinctions among fat depots.
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Affiliation(s)
- Guoqing Wang
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Carli A Williams
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Betty R McConn
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Mark A Cline
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Elizabeth R Gilbert
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
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West KS, Roseberry AG. Neuropeptide-Y alters VTA dopamine neuron activity through both pre- and postsynaptic mechanisms. J Neurophysiol 2017; 118:625-633. [PMID: 28469002 DOI: 10.1152/jn.00879.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 11/22/2022] Open
Abstract
The mesocorticolimbic dopamine system, the brain's reward system, regulates many different behaviors including food intake, food reward, and feeding-related behaviors, and there is increasing evidence that hypothalamic feeding-related neuropeptides alter dopamine neuron activity to affect feeding. For example, neuropeptide-Y (NPY), a strong orexigenic hypothalamic neuropeptide, increases motivation for food when injected into the ventral tegmental area (VTA). How NPY affects the activity of VTA dopamine neurons to regulate feeding behavior is unknown, however. In these studies we have used whole cell patch-clamp electrophysiology in acute brain slices from mice to examine how NPY affects VTA dopamine neuron activity. NPY activated an outward current that exhibited characteristics of a G protein-coupled inwardly rectifying potassium channel current in ~60% of dopamine neurons tested. In addition to its direct effects on VTA dopamine neurons, NPY also decreased the amplitude and increased paired-pulse ratios of evoked excitatory postsynaptic currents in a subset of dopamine neurons, suggesting that NPY decreases glutamatergic transmission through a presynaptic mechanism. Interestingly, NPY also strongly inhibited evoked inhibitory postsynaptic currents onto dopamine neurons by a presynaptic mechanism. Overall these studies demonstrate that NPY utilizes multiple mechanisms to affect VTA dopamine neuron activity, and they provide an important advancement in our understanding of how NPY acts in the VTA to control feeding behavior.NEW & NOTEWORTHY Neuropeptide-Y (NPY) has been shown to act on mesolimbic dopamine circuits to increase motivated behaviors toward food, but it is unclear exactly how NPY causes these responses. Here, we demonstrate that NPY directly inhibited a subset of ventral tegmental area (VTA) dopamine neurons through the activation of G protein-coupled inwardly rectifying potassium currents, and it inhibited both excitatory postsynaptic currents and inhibitory postsynaptic currents onto subsets of dopamine neurons through a presynaptic mechanism. Thus NPY uses multiple mechanisms to dynamically control VTA dopamine neuron activity.
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Affiliation(s)
- Katherine Stuhrman West
- Department of Biology, Georgia State University, Atlanta, Georgia.,The Neuroscience Institute, Georgia State University, Atlanta, Georgia; and
| | - Aaron G Roseberry
- Department of Biology, Georgia State University, Atlanta, Georgia; .,The Neuroscience Institute, Georgia State University, Atlanta, Georgia; and.,The Center for Obesity Reversal, Georgia State University, Atlanta, Georgia
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Coccurello R, Romano A, Giacovazzo G, Tempesta B, Fiore M, Giudetti AM, Marrocco I, Altieri F, Moles A, Gaetani S. Increased intake of energy-dense diet and negative energy balance in a mouse model of chronic psychosocial defeat. Eur J Nutr 2017; 57:1485-1498. [PMID: 28314964 DOI: 10.1007/s00394-017-1434-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 03/06/2017] [Indexed: 02/06/2023]
Abstract
PURPOSE Chronic exposure to stress may represent a risk factor for developing metabolic and eating disorders, mostly driven by the overconsumption of easily accessible energy-dense palatable food, although the mechanisms involved remain still unclear. In this study, we used an ethologically oriented murine model of chronic stress caused by chronic psychosocial defeat (CPD) to investigate the effects of unrestricted access to a palatable high fat diet (HFD) on food intake, body weight, energy homeostasis, and expression of different brain neuropeptides. Our aim was to shed light on the mechanisms responsible for body weight and body composition changes due to chronic social stress. METHODS In our model of subordinate (defeated), mice (CPD) cohabitated in constant sensory contact with dominants, being forced to interact on daily basis, and were offered ad libitum access either to an HFD or to a control diet (CD). Control mice (of the same strain as CPD mice) were housed in pairs and left unstressed in their home cage (UN). In all these mice, we evaluated body weight, different adipose depots, energy metabolism, caloric intake, and neuropeptide expression. RESULTS CPD mice increased the intake of HFD and reduced body weight in the presence of enhanced lipid oxidation. Resting energy expenditure and interscapular brown adipose tissue (iBAT) were increased in CPD mice, whereas epididymal adipose tissue increased only in HFD-fed unstressed mice. Propiomelanocortin mRNA levels in hypothalamic arcuate nucleus increased only in HFD-fed unstressed mice. Oxytocin mRNA levels in the paraventricular nucleus and neuropeptide Y mRNA levels within the arcuate were increased only in CD-fed CPD mice. In the arcuate, CART was increased in HFD-fed UN mice and in CD-fed CPD mice, while HFD intake suppressed CART increase in defeated animals. In the basolateral amygdala, CART expression was increased only in CPD animals on HFD. CONCLUSIONS CPD appears to uncouple the intake of HFD from energy homeostasis causing higher HFD intake, larger iBAT accumulation, increased energy expenditure and lipid oxidation, and lower body weight. Overall, the present study confirms the notion that the chronic activation of the stress response can be associated with metabolic disorders, altered energy homeostasis, and changes of orexigenic and anorexigenic signaling. These changes might be relevant to better understand the etiology of stress-induced obesity and eating disorders and might represent a valid therapeutic approach for the development of new therapies in this field.
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Affiliation(s)
- Roberto Coccurello
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via del Fosso di Fiorano, 64, 00143, Roma, Italy. .,Fondazione Santa Lucia (FSL-IRCCS), Via del Fosso di Fiorano, 64, 00143, Roma, Italy.
| | - Adele Romano
- Department of Physiology and Pharmacology V. Erspamer, Sapienza University of Rome, P.le A. Moro, 5, 00185, Roma, Italy
| | - Giacomo Giacovazzo
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via del Fosso di Fiorano, 64, 00143, Roma, Italy.,Fondazione Santa Lucia (FSL-IRCCS), Via del Fosso di Fiorano, 64, 00143, Roma, Italy
| | - Bianca Tempesta
- Department of Physiology and Pharmacology V. Erspamer, Sapienza University of Rome, P.le A. Moro, 5, 00185, Roma, Italy
| | - Marco Fiore
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via del Fosso di Fiorano, 64, 00143, Roma, Italy.,Fondazione Santa Lucia (FSL-IRCCS), Via del Fosso di Fiorano, 64, 00143, Roma, Italy
| | - Anna Maria Giudetti
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
| | - Ilaria Marrocco
- Department of Biochemical Sciences, Sapienza University of Rome, P.le A. Moro, 5, 00185, Roma, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Viale Regina Elena, 291, 00161, Roma, Italy
| | - Fabio Altieri
- Department of Biochemical Sciences, Sapienza University of Rome, P.le A. Moro, 5, 00185, Roma, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Viale Regina Elena, 291, 00161, Roma, Italy
| | - Anna Moles
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via del Fosso di Fiorano, 64, 00143, Roma, Italy. .,Genomia srl, Via L. Ariosto 21, 20091, Bresso, Milan, Italy.
| | - Silvana Gaetani
- Department of Physiology and Pharmacology V. Erspamer, Sapienza University of Rome, P.le A. Moro, 5, 00185, Roma, Italy
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Eshragh J, Dhruva A, Paul SM, Cooper BA, Mastick J, Hamolsky D, Levine JD, Miaskowski C, Kober KM. Associations Between Neurotransmitter Genes and Fatigue and Energy Levels in Women After Breast Cancer Surgery. J Pain Symptom Manage 2017; 53:67-84.e7. [PMID: 27720787 PMCID: PMC5191954 DOI: 10.1016/j.jpainsymman.2016.08.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/19/2016] [Accepted: 08/03/2016] [Indexed: 12/16/2022]
Abstract
CONTEXT Fatigue is a common problem in oncology patients. Less is known about decrements in energy levels and the mechanisms that underlie both fatigue and energy. OBJECTIVES In patients with breast cancer, variations in neurotransmitter genes between lower and higher fatigue latent classes and between the higher and lower energy latent classes were evaluated. METHODS Patients completed assessments before and monthly for six months after surgery. Growth mixture modeling was used to identify distinct latent classes for fatigue severity and energy levels. Thirty candidate genes involved in various aspects of neurotransmission were evaluated. RESULTS Eleven single-nucleotide polymorphisms or haplotypes (i.e., ADRB2 rs1042718, BDNF rs6265, COMT rs9332377, CYP3A4 rs4646437, GALR1 rs949060, GCH1 rs3783642, NOS1 rs9658498, NOS1 rs2293052, NPY1R Haplotype A04, SLC6A2 rs17841327, and 5HTTLPR + rs25531 in SLC6A4) were associated with latent class membership for fatigue. Seven single-nucleotide polymorphisms or haplotypes (i.e., NOS1 rs471871, SLC6A1 rs2675163, SLC6A1 Haplotype D01, SLC6A2 rs36027, SLC6A3 rs37022, SLC6A4 rs2020942, and TAC1 rs2072100) were associated with latent class membership for energy. Three of 13 genes (i.e., NOS1, SLC6A2, and SLC6A4) were associated with latent class membership for both fatigue and energy. CONCLUSIONS Molecular findings support the hypothesis that fatigue and energy are distinct, yet related symptoms. Results suggest that a large number of neurotransmitters play a role in the development and maintenance of fatigue and energy levels in breast cancer patients.
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Affiliation(s)
- Jasmine Eshragh
- School of Nursing, University of California, San Francisco, California, USA
| | - Anand Dhruva
- School of Medicine, University of California, San Francisco, California, USA
| | - Steven M Paul
- School of Nursing, University of California, San Francisco, California, USA
| | - Bruce A Cooper
- School of Nursing, University of California, San Francisco, California, USA
| | - Judy Mastick
- School of Nursing, University of California, San Francisco, California, USA
| | - Deborah Hamolsky
- School of Nursing, University of California, San Francisco, California, USA
| | - Jon D Levine
- School of Medicine, University of California, San Francisco, California, USA
| | | | - Kord M Kober
- School of Nursing, University of California, San Francisco, California, USA.
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7
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Roles of NMDA and dopamine in food-foraging decision-making strategies of rats in the social setting. BMC Neurosci 2016; 17:3. [PMID: 26754043 PMCID: PMC4710019 DOI: 10.1186/s12868-015-0233-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 12/08/2015] [Indexed: 01/15/2023] Open
Abstract
Background
In highly complex social settings, an animal’s motivational drive to pursue an object depends not only on the intrinsic properties of the object, but also on whether the decision-making animal perceives an object as being the most desirable among others. Mimetic desire refers to a subject’s preference for objects already possessed by another subject. To date, there are no appropriate animal models for studying whether mimetic desire is at play in guiding the decision-making process. Furthermore, the neuropharmacological bases of decision-making processes are not well understood. In this study, we used an animal model (rat) to investigate a novel food-foraging paradigm for decision-making, with or without a mimetic desire paradigm. Results Faced with the choice of foraging in a competitive environment, rats preferred foraging for the desirable object, indicating the rats’ ability for decision-making. Notably, treatment with the non-competitive N-methyl-d-aspartate receptor antagonist MK-801, but not with the dopamine D1 or D2 receptor antagonists, SCH23390 and haloperidol, respectively, suppressed the food foraging preference when there was a competing resident rat in the cage. None of these three antagonists affected the food-foraging preference for palatable food. Moreover, MK-801 and SCH23390, but not haloperidol, were able to abolish the desirable environment effect on standard food-foraging activities in complex social settings. Conclusions These results highlight the concept that mimetic desire exerts a powerful influence on food-foraging decision-making in rats and, further, illustrate the various roles of the glutamatergic and dopaminergic systems in mediating these processes.
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Nakajima KI, Cui Z, Li C, Meister J, Cui Y, Fu O, Smith AS, Jain S, Lowell BB, Krashes MJ, Wess J. Gs-coupled GPCR signalling in AgRP neurons triggers sustained increase in food intake. Nat Commun 2016; 7:10268. [PMID: 26743492 PMCID: PMC4729878 DOI: 10.1038/ncomms10268] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 11/24/2015] [Indexed: 01/06/2023] Open
Abstract
Agouti-related peptide (AgRP) neurons of the hypothalamus play a key role in regulating food intake and body weight, by releasing three different orexigenic molecules: AgRP; GABA; and neuropeptide Y. AgRP neurons express various G protein-coupled receptors (GPCRs) with different coupling properties, including Gs-linked GPCRs. At present, the potential role of Gs-coupled GPCRs in regulating the activity of AgRP neurons remains unknown. Here we show that the activation of Gs-coupled receptors expressed by AgRP neurons leads to a robust and sustained increase in food intake. We also provide detailed mechanistic data linking the stimulation of this class of receptors to the observed feeding phenotype. Moreover, we show that this pathway is clearly distinct from other GPCR signalling cascades that are operative in AgRP neurons. Our data suggest that drugs able to inhibit this signalling pathway may become useful for the treatment of obesity. Hypothalamic Agouti-related peptide (AgRP) neurons play a key role in regulating food intake. Here, the authors report a novel pathway in which activation of Gs-coupled receptors on AgRP neurons leads to robust, sustained increase in food intake.
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Affiliation(s)
- Ken-ichiro Nakajima
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Zhenzhong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Chia Li
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jaroslawna Meister
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Ou Fu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 1138657, Japan
| | - Adam S Smith
- Section on Neural Gene Expression, National Institute of Mental Health, Bethesda, Maryland 20892, USA
| | - Shalini Jain
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Bradford B Lowell
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael J Krashes
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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9
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Luo G, Xu X, Guo W, Luo C, Wang H, Meng X, Zhu S, Wei Y. Neuropeptide Y damages the integrity of mitochondrial structure and disrupts energy metabolism in cultured neonatal rat cardiomyocytes. Peptides 2015; 71:162-9. [PMID: 26188175 DOI: 10.1016/j.peptides.2015.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 06/28/2015] [Accepted: 07/03/2015] [Indexed: 01/05/2023]
Abstract
Neuropeptide Y (NPY) plays an important role in cardiovascular diseases including stress cardiomyopathy, hypertrophic cardiomyopathy, heart failure, diabetic cardiomyopathy, hypertension, and so on. However, inconsistent results related to the role of NPY in the different types of cardiomyopathies make the exact involvement of the peptide elusive. Considering these effects are known to be involved in energy balance, as the hearts energy producer, the mitochondria, should be investigated, and not only mitochondrial structure but also its potential. Up to now, the impact of NPY on energy metabolism and mitochondria in cultured neonatal rat cardiomyocytes has not been reported. The main objective of our study was to test the role of NPY in cultured neonatal rat cardiomyocytes. After 24-h stimulation of NPY, the ATP content and activity of the cardiomyocytes were determined by Cell Counting Kit-8 and ATP-dependent bioluminescence assay kit, respectively. To further measure these effects, mitochondrial membrane potential was measured by JC-1 staining, the change of mitochondrial structure was detected by transmission electron microscopy, and the levels of PGC-1α (a marker of mitochondrial energy metabolism) mRNA and protein expression were determined by real-time PCR and Western blotting, respectively. The results showed that after 24-h stimulation of NPY, ATP content and activity in the cardiomyocytes were decreased. Moreover, cardiomyocyte mitochondria were changed in morphology. Further, a decline of mitochondrial membrane potential was induced in a dose-dependent manner and the levels of PGC-1α mRNA and protein expression were up-regulated after being treated by different dose of NPY. The results indicate that energy metabolism is suppressed, mitochondrial structure and membrane potential damaged, and PGC-α is changed in cultured neonatal rat cardiomyocytes after being treated by NPY.
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Affiliation(s)
- Guochang Luo
- Department of Forensic Medicine, Wuhan University School of Basic Medical Science, Wuhan, PR China; Department of Basic Medicine, Nanyang Medical College, Henan, PR China
| | - Xuehua Xu
- Department of Forensic Medicine, Soochow University, Suzhou, PR China
| | - Wei Guo
- Department of Forensic Medicine, Wuhan University School of Basic Medical Science, Wuhan, PR China
| | - Chengliang Luo
- Department of Forensic Medicine, Soochow University, Suzhou, PR China
| | - Hao Wang
- Department of Forensic Medicine, Wuhan University School of Basic Medical Science, Wuhan, PR China
| | - Xiangzhi Meng
- Department of Forensic Medicine, Wuhan University School of Basic Medical Science, Wuhan, PR China.
| | - Shaohua Zhu
- Department of Forensic Medicine, Soochow University, Suzhou, PR China
| | - Yan Wei
- Department of Basic Medicine, Nanyang Medical College, Henan, PR China
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10
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Martins J, Elvas F, Brudzewsky D, Martins T, Kolomiets B, Tralhão P, Gøtzsche CR, Cavadas C, Castelo-Branco M, Woldbye DPD, Picaud S, Santiago AR, Ambrósio AF. Activation of Neuropeptide Y Receptors Modulates Retinal Ganglion Cell Physiology and Exerts Neuroprotective Actions In Vitro. ASN Neuro 2015; 7:7/4/1759091415598292. [PMID: 26311075 PMCID: PMC4552225 DOI: 10.1177/1759091415598292] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuropeptide Y (NPY) is expressed in mammalian retina but the location and potential modulatory effects of NPY receptor activation remain largely unknown. Retinal ganglion cell (RGC) death is a hallmark of several retinal degenerative diseases, particularly glaucoma. Using purified RGCs and ex vivo rat retinal preparations, we have measured RGC intracellular free calcium concentration ([Ca2+]i) and RGC spiking activity, respectively. We found that NPY attenuated the increase in the [Ca2+]i triggered by glutamate mainly via Y1 receptor activation. Moreover, (Leu31, Pro34)−NPY, a Y1/Y5 receptor agonist, increased the initial burst response of OFF-type RGCs, although no effect was observed on RGC spontaneous spiking activity. The Y1 receptor activation was also able to directly modulate RGC responses by attenuating the NMDA-induced increase in RGC spiking activity. These results suggest that Y1 receptor activation, at the level of inner or outer plexiform layers, leads to modulation of RGC receptive field properties. Using in vitro cultures of rat retinal explants exposed to NMDA, we found that NPY pretreatment prevented NMDA-induced cell death. However, in an animal model of retinal ischemia-reperfusion injury, pretreatment with NPY or (Leu31, Pro34)−NPY was not able to prevent apoptosis or rescue RGCs. In conclusion, we found modulatory effects of NPY application that for the first time were detected at the level of RGCs. However, further studies are needed to evaluate whether NPY neuroprotective actions detected in retinal explants can be translated into animal models of retinal degenerative diseases.
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Affiliation(s)
- João Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Dan Brudzewsky
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Tânia Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Bogdan Kolomiets
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Pedro Tralhão
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Casper R Gøtzsche
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Cláudia Cavadas
- CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Miguel Castelo-Branco
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - David P D Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Serge Picaud
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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11
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Abstract
Obesity ensues from an imbalance between energy intake and expenditure that results from gene-environment interactions, which favour a positive energy balance. A society that promotes unhealthy food and encourages sedentary lifestyle (that is, an obesogenic environment) has become a major contributory factor in excess fat deposition in individuals predisposed to obesity. Energy homeostasis relies upon control of energy intake as well as expenditure, which is in part determined by the themogenesis of brown adipose tissue and mediated by the sympathetic nervous system. Several areas of the brain that constitute cognitive and autonomic brain systems, which in turn form networks involved in the control of appetite and thermogenesis, also contribute to energy homeostasis. These networks include the dopamine mesolimbic circuit, as well as the opioid, endocannabinoid and melanocortin systems. The activity of these networks is modulated by peripheral factors such as hormones derived from adipose tissue and the gut, which access the brain via the circulation and neuronal signalling pathways to inform the central nervous system about energy balance and nutritional status. In this Review, I focus on the determinants of energy homeostasis that have emerged as prominent factors relevant to obesity.
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Affiliation(s)
- Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, 2725 Chemin Sainte-Foy, Québec, QC G1V 4G5, Canada
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12
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Transient expression of neuropeptide W in postnatal mouse hypothalamus--a putative regulator of energy homeostasis. Neuroscience 2015; 301:323-37. [PMID: 26073698 DOI: 10.1016/j.neuroscience.2015.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/29/2015] [Accepted: 06/06/2015] [Indexed: 11/24/2022]
Abstract
Neuropeptide B and W (NPB and NPW) are cognate peptide ligands for NPBWR1 (GPR7), a G protein-coupled receptor. In rodents, they have been implicated in the regulation of energy homeostasis, neuroendocrine/autonomic responses, and social interactions. Although localization of these peptides and their receptors in adult rodent brain has been well documented, their expression in mouse brain during development is unknown. Here we demonstrate the transient expression of NPW mRNA in the dorsomedial hypothalamus (DMH) of postnatal mouse brain and its co-localization with neuropeptide Y (NPY) mRNA. Neurons expressing both NPW and NPY mRNAs begin to emerge in the DMH at about postnatal day 0 (P-0) through P-3. Their expression is highest around P-14, declines after P-21, and by P-28 only a faint expression of NPW and NPY mRNA remains. In P-18 brains, we detected NPW neurons in the region spanning the subincertal nucleus (SubI), the lateral hypothalamic (LH) perifornical (PF) areas, and the DMH, where the highest expression of NPW mRNA was observed. The majority of these postnatal hypothalamic NPW neurons co-express NPY mRNA. A cross of NPW-iCre knock-in mice with a Cre-dependent tdTomato reporter line revealed that more than half of the reporter-positive neurons in the adult DMH, which mature from the transiently NPW-expressing neurons, are sensitive to peripherally administrated leptin. These data suggest that the DMH neurons that transiently co-express NPW and NPY in the peri-weaning period might play a role in regulating energy homeostasis during postnatal development.
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13
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Wang F, Kohan AB, Lo CM, Liu M, Howles P, Tso P. Apolipoprotein A-IV: a protein intimately involved in metabolism. J Lipid Res 2015; 56:1403-18. [PMID: 25640749 DOI: 10.1194/jlr.r052753] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Indexed: 01/07/2023] Open
Abstract
The purpose of this review is to summarize our current understanding of the physiological roles of apoA-IV in metabolism, and to underscore the potential for apoA-IV to be a focus for new therapies aimed at the treatment of diabetes and obesity-related disorders. ApoA-IV is primarily synthesized by the small intestine, attached to chylomicrons by enterocytes, and secreted into intestinal lymph during fat absorption. In circulation, apoA-IV is associated with HDL and chylomicron remnants, but a large portion is lipoprotein free. Due to its anti-oxidative and anti-inflammatory properties, and because it can mediate reverse-cholesterol transport, proposed functions of circulating apoA-IV have been related to protection from cardiovascular disease. This review, however, focuses primarily on several properties of apoA-IV that impact other metabolic functions related to food intake, obesity, and diabetes. In addition to participating in triglyceride absorption, apoA-IV can act as an acute satiation factor through both peripheral and central routes of action. It also modulates glucose homeostasis through incretin-like effects on insulin secretion, and by moderating hepatic glucose production. While apoA-IV receptors remain to be conclusively identified, the latter modes of action suggest that this protein holds therapeutic promise for treating metabolic disease.
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Affiliation(s)
- Fei Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Alison B Kohan
- Department of Nutritional Sciences, University of Connecticut Advanced Technology Laboratory, Storrs, CT 06269
| | - Chun-Min Lo
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Philip Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
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14
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Cassaglia PA, Shi Z, Li B, Reis WL, Clute-Reinig NM, Stern JE, Brooks VL. Neuropeptide Y acts in the paraventricular nucleus to suppress sympathetic nerve activity and its baroreflex regulation. J Physiol 2014; 592:1655-75. [PMID: 24535439 DOI: 10.1113/jphysiol.2013.268763] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neuropeptide Y (NPY), a brain neuromodulator that has been strongly implicated in the regulation of energy balance, also acts centrally to inhibit sympathetic nerve activity (SNA); however, the site and mechanism of action are unknown. In chloralose-anaesthetized female rats, nanoinjection of NPY into the paraventricular nucleus of the hypothalamus (PVN) dose-dependently suppressed lumbar SNA (LSNA) and its baroreflex regulation, and these effects were blocked by prior inhibition of NPY Y1 or Y5 receptors. Moreover, PVN injection of Y1 and Y5 receptor antagonists in otherwise untreated rats increased basal and baroreflex control of LSNA, indicating that endogenous NPY tonically inhibits PVN presympathetic neurons. The sympathoexcitation following blockade of PVN NPY inhibition was eliminated by prior PVN nanoinjection of the melanocortin 3/4 receptor inhibitor SHU9119. Moreover, presympathetic neurons, identified immunohistochemically using cholera toxin b neuronal tract tracing from the rostral ventrolateral medulla (RVLM), express NPY Y1 receptor immunoreactivity, and patch-clamp recordings revealed that both NPY and α-melanocyte-stimulating hormone (α-MSH) inhibit and stimulate, respectively, PVN-RVLM neurons. Collectively, these data suggest that PVN NPY inputs converge with α-MSH to influence presympathetic neurons. Together these results identify endogenous NPY as a novel and potent inhibitory neuromodulator within the PVN that may contribute to changes in SNA that occur in states associated with altered energy balance, such as obesity and pregnancy.
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Affiliation(s)
- Priscila A Cassaglia
- Oregon Health & Science University, Department of Physiology and Pharmacology, 1381 SW Sam Jackson Park Rd - L334, Portland, OR 97239, USA.
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15
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Geerling JJ, Boon MR, Kooijman S, Parlevliet ET, Havekes LM, Romijn JA, Meurs IM, Rensen PCN. Sympathetic nervous system control of triglyceride metabolism: novel concepts derived from recent studies. J Lipid Res 2014; 55:180-9. [PMID: 24285857 PMCID: PMC3886657 DOI: 10.1194/jlr.r045013] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/27/2013] [Indexed: 12/16/2022] Open
Abstract
Important players in triglyceride (TG) metabolism include the liver (production), white adipose tissue (WAT) (storage), heart and skeletal muscle (combustion to generate ATP), and brown adipose tissue (BAT) (combustion toward heat), the collective action of which determine plasma TG levels. Interestingly, recent evidence points to a prominent role of the hypothalamus in TG metabolism through innervating the liver, WAT, and BAT mainly via sympathetic branches of the autonomic nervous system. Here, we review the recent findings in the area of sympathetic control of TG metabolism. Various neuronal populations, such as neuropeptide Y (NPY)-expressing neurons and melanocortin-expressing neurons, as well as peripherally produced hormones (i.e., GLP-1, leptin, and insulin), modulate sympathetic outflow from the hypothalamus toward target organs and thereby influence peripheral TG metabolism. We conclude that sympathetic stimulation in general increases lipolysis in WAT, enhances VLDL-TG production by the liver, and increases the activity of BAT with respect to lipolysis of TG, followed by combustion of fatty acids toward heat. Moreover, the increased knowledge about the involvement of the neuroendocrine system in TG metabolism presented in this review offers new therapeutic options to fight hypertriglyceridemia by specifically modulating sympathetic nervous system outflow toward liver, BAT, or WAT.
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Affiliation(s)
- Janine J. Geerling
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mariëtte R. Boon
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Sander Kooijman
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Edwin T. Parlevliet
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
- Department of Medicine, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Louis M. Havekes
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
- Gaubius Laboratory, Netherlands Organization for Applied Scientific Research - Metabolic Health Research, Leiden, The Netherlands
| | - Johannes A. Romijn
- Department of Medicine, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Illiana M. Meurs
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Patrick C. N. Rensen
- Departments of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
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16
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Heng BC, Aubel D, Fussenegger M. An overview of the diverse roles of G-protein coupled receptors (GPCRs) in the pathophysiology of various human diseases. Biotechnol Adv 2013; 31:1676-94. [DOI: 10.1016/j.biotechadv.2013.08.017] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 12/23/2022]
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17
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Abstract
Individual meals are products of a complex interaction of signals related to both short-term and long-term availability of energy stores. In addition to maintaining the metabolic demands of the individual in the short term, levels of energy intake must also maintain and defend body weight over longer periods. To accomplish this, satiety pathways are regulated by a sophisticated network of endocrine and neuroendocrine pathways. Higher brain centers modulate meal size through descending inputs to caudal brainstem regions responsible for the motor pattern generators associated with ingestion. Gastric and intestinal signals interact with central nervous system pathways to terminate food intake. These inputs can be modified as a function of internal metabolic signals, external environmental influences, and learning to regulate meal size.
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18
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Association of age at onset in Huntington disease with functional promoter variations in NPY and NPY2R. J Mol Med (Berl) 2013; 92:177-84. [DOI: 10.1007/s00109-013-1092-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 09/09/2013] [Accepted: 10/02/2013] [Indexed: 12/23/2022]
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19
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Frese CK, Boender AJ, Mohammed S, Heck AJR, Adan RAH, Altelaar AFM. Profiling of diet-induced neuropeptide changes in rat brain by quantitative mass spectrometry. Anal Chem 2013; 85:4594-604. [PMID: 23581470 DOI: 10.1021/ac400232y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neuropeptides are intercellular signal transmitters that play key roles in modulation of many behavioral and physiological processes. Neuropeptide signaling in several nuclei in the hypothalamus contributes to the control of food intake. Additionally, food intake regulation involves neuropeptide signaling in the reward circuitry in the striatum. Here, we analyze neuropeptides extracted from hypothalamus and striatum from rats in four differentially treated dietary groups including a high-fat/high-sucrose diet, mimicking diet-induced obesity. We employ high-resolution tandem mass spectrometry using higher-energy collision dissociation and electron transfer dissociation fragmentation for sensitive identification of more than 1700 unique endogenous peptides, including virtually all key neuropeptides known to be involved in food intake regulation. Label-free quantification of differential neuropeptide expression revealed comparable upregulation of orexigenic and anorexigenic neuropeptides in rats that were fed on a high-fat/high-sucrose diet.
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Affiliation(s)
- Christian K Frese
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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20
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Acute central neuropeptide Y administration increases food intake but does not affect hepatic very low-density lipoprotein (VLDL) production in mice. PLoS One 2013; 8:e55217. [PMID: 23460782 PMCID: PMC3584102 DOI: 10.1371/journal.pone.0055217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 12/20/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Central neuropeptide Y (NPY) administration stimulates food intake in rodents. In addition, acute modulation of central NPY signaling increases hepatic production of very low-density lipoprotein (VLDL)-triglyceride (TG) in rats. As hypertriglyceridemia is an important risk factor for atherosclerosis, for which well-established mouse models are available, we set out to validate the effect of NPY on hepatic VLDL-TG production in mice, to ultimately investigate whether NPY, by increasing VLDL production, contributes to the development of atherosclerosis. RESEARCH DESIGN AND METHODS Male C57Bl/6J mice received an intracerebroventricular (i.c.v.) cannula into the lateral (LV) or third (3V) ventricle of the brain. One week later, after a 4 h fast, the animals received an intravenous (i.v.) injection of Tran(35)S (100 µCi) followed by tyloxapol (500 mg/kg body weight; BW), enabling the study of hepatic VLDL-apoB and VLDL-TG production, respectively. Immediately after the i.v. injection of tyloxapol, the animals received either an i.c.v. injection of NPY (0.2 mg/kg BW in artificial cerebrospinal fluid; aCSF), synthetic Y1 receptor antagonist GR231118 (0.5 mg/kg BW in aCSF) or vehicle (aCSF), or an i.v. injection of PYY3-36 (0.5 mg/kg BW in PBS) or vehicle (PBS). RESULTS Administration of NPY into both the LV and 3V increased food intake within one hour after injection (+164%, p<0.001 and +367%, p<0.001, respectively). NPY administration neither in the LV nor in the 3V affected hepatic VLDL-TG or VLDL-apoB production. Likewise, antagonizing central NPY signaling by either PYY3-36 or GR231118 administration did not affect hepatic VLDL production. CONCLUSION In mice, as opposed to rats, acute central administration of NPY increases food intake without affecting hepatic VLDL production. These results are of great significance when extrapolating findings on the central regulation of hepatic VLDL production between species.
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21
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Panickar KS. Effects of dietary polyphenols on neuroregulatory factors and pathways that mediate food intake and energy regulation in obesity. Mol Nutr Food Res 2012; 57:34-47. [DOI: 10.1002/mnfr.201200431] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/08/2012] [Accepted: 08/22/2012] [Indexed: 12/20/2022]
Affiliation(s)
- Kiran S. Panickar
- Department of Pediatrics; University of Maryland School of Medicine; Baltimore MD USA
- Diet, Genomics, & Immunology Laboratory; Beltsville Human Nutrition Research Center; Agricultural Research Service; United States Department of Agriculture; Beltsville MD USA
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