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Yanagida S, Motomura K, Ohashi A, Hiraoka K, Miura T, Kanba S. Effect of acute imipramine administration on the pattern of forced swim-induced c-Fos expression in the mouse brain. Neurosci Lett 2016; 629:119-124. [DOI: 10.1016/j.neulet.2016.06.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/20/2016] [Accepted: 06/27/2016] [Indexed: 11/16/2022]
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Chaly AL, Srisai D, Gardner EE, Sebag JA. The Melanocortin Receptor Accessory Protein 2 promotes food intake through inhibition of the Prokineticin Receptor-1. eLife 2016; 5. [PMID: 26829592 PMCID: PMC4786424 DOI: 10.7554/elife.12397] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 01/31/2016] [Indexed: 12/25/2022] Open
Abstract
The Melanocortin Receptor Accessory Protein 2 (MRAP2) is an important regulator of energy homeostasis and its loss causes severe obesity in rodents. MRAP2 mediates its action in part through the potentiation of the MC4R, however, it is clear that MRAP2 is expressed in tissues that do not express MC4R, and that the deletion of MRAP2 does not recapitulate the phenotype of Mc4r KO mice. Consequently, we hypothesized that other GPCRs involved in the control of energy homeostasis are likely to be regulated by MRAP2. In this study we identified PKR1 as the first non-melanocortin GPCR to be regulated by MRAP2. We show that MRAP2 significantly and specifically inhibits PKR1 signaling. We also demonstrate that PKR1 and MRAP2 co-localize in neurons and that Mrap2 KO mice are hypersensitive to PKR1 stimulation. This study not only identifies new partners of MRAP2 but also a new pathway through which MRAP2 regulates energy homeostasis. DOI:http://dx.doi.org/10.7554/eLife.12397.001 The brain plays a major role in controlling how much food animals eat. The nerve cells (neurons) involved in this process contain “receptors” that respond to cues from various parts of the body. For example, a receptor called PKR1 acts to limit food intake. The activities of PKR1 and other receptors are tightly regulated in cells, but it is not clear how this works. A protein called MRAP2 is known to regulate the activity of a receptor that regulates food intake and energy use in the brain. However, MRAP2 may also interact with other receptors to control food intake. Here, Chaly, Srisai et al. investigated whether MRAP2 can regulate the activity of PKR1 in animal cells and rodents. The experiments show that MRAP2 can interact with and inhibit the activity of PKR1. Furthermore, both MRAP2 and PKR1 can be found in the same neurons. Mutant mice that lack the gene that encodes MRAP2 have higher levels of PKR1 activity and eat less than normal mice when PKR1 is stimulated. Together the experiments suggest that MRAP2 can increase food intake by preventing PKR1 from being activated in the brain. The next steps are to find out if this protein regulates other receptors involved in the control of food intake, and to test whether PKR1 and MRAP2 also play a role in regulating energy usage. DOI:http://dx.doi.org/10.7554/eLife.12397.002
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Affiliation(s)
- Anna L Chaly
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, United States
| | - Dollada Srisai
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, United States
| | - Ellen E Gardner
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, United States
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, United States.,Pappajohn Biomedical Institute, University of Iowa, Iowa City, United States
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Boswell T, Dunn IC. Regulation of the avian central melanocortin system and the role of leptin. Gen Comp Endocrinol 2015; 221:278-83. [PMID: 25583584 DOI: 10.1016/j.ygcen.2014.12.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 12/19/2014] [Indexed: 01/10/2023]
Abstract
The avian central melanocortin system is well conserved between birds and mammals in terms of the component genes, the localisation of their expression in the hypothalamic arcuate nucleus, the effects on feeding behaviour of their encoded peptides and the sensitivity of agouti-related protein (AGRP) and pro-opiomelanocortin (POMC) gene expression to changes in energy status. Our recent research has demonstrated that AGRP gene expression precisely differentiates between broiler breeder hens with different histories of chronic food restriction and refeeding. We have also shown that the sensitivity of AGRP gene expression to loss of energy stores is maintained even when food intake has been voluntarily reduced in chickens during incubation and in response to a stressor. However, the similarity between birds and mammals does not appear to extend to the way AGRP and POMC gene expression are regulated. In particular, the preliminary evidence from the discovery of the first avian leptin (LEP) genes suggests that LEP is more pleiotropic in birds and may not even be involved in regulating energy balance. Similarly, ghrelin exerts inhibitory, rather than stimulatory, effects on food intake. The fact that the importance of these prominent long-term regulators of AGRP and POMC expression in mammals appears diminished in birds suggests that the balance of regulatory inputs in birds may have shifted to more short-term influences such as the tone of cholecystokinin (CCK) signalling. This is likely to be related to the different metabolic fuelling required to support flight.
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Affiliation(s)
- Timothy Boswell
- School of Biology, Institute of Neuroscience, Centre for Behaviour and Evolution, Newcastle University, England, United Kingdom.
| | - Ian C Dunn
- Royal (Dick) School of Veterinary Studies, Roslin Institute, University of Edinburgh, Easter Bush, Scotland, United Kingdom
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Dunn IC, Wilson PW, D'Eath RB, Boswell T. Hypothalamic Agouti-Related Peptide mRNA is Elevated During Natural and Stress-Induced Anorexia. J Neuroendocrinol 2015; 27:681-91. [PMID: 26017156 PMCID: PMC4973702 DOI: 10.1111/jne.12295] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 01/14/2023]
Abstract
As part of their natural lives, animals can undergo periods of voluntarily reduced food intake and body weight (i.e. animal anorexias) that are beneficial for survival or breeding, such as during territorial behaviour, hibernation, migration and incubation of eggs. For incubation, a change in the defended level of body weight or 'sliding set point' appears to be involved, although the neural mechanisms reponsible for this are unknown. We investigated how neuropeptide gene expression in the arcuate nucleus of the domestic chicken responded to a 60-70% voluntary reduction in food intake measured both after incubation and after an environmental stressor involving transfer to unfamiliar housing. We hypothesised that gene expression would not change in these circumstances because the reduced food intake and body weight represented a defended level in birds with free access to food. Unexpectedly, we observed increased gene expression of the orexigenic peptide agouti-related peptide (AgRP) in both incubating and transferred animals compared to controls. Also pro-opiomelanocortin (POMC) mRNA was higher in incubating hens and significantly increased 6 days after exposure to the stressor. Conversely expression of neuropeptide Y and cocaine- and amphetamine-regulated transcript gene was unchanged in both experimental situations. We conclude that AgRP expression remains sensitive to the level of energy stores during natural anorexias, which is of adaptive advantage, although its normal orexigenic effects are over-ridden by inhibitory signals. In the case of stress-induced anorexia, increased POMC may contribute to this inhibitory role, whereas, for incubation, reduced feeding may also be associated with increased expression in the hypothalamus of the anorexigenic peptide vasoactive intestinal peptide.
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Affiliation(s)
- I C Dunn
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - P W Wilson
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - R B D'Eath
- Animal Behaviour & Welfare, Veterinary Science Research Group, SRUC, West Mains Road, Edinburgh, EH9 3JG, UK
| | - T Boswell
- School of Biology, Centre for Behaviour and Evolution, Newcastle University, Newcastle-Upon-Tyne, UK
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55
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Méquinion M, Chauveau C, Viltart O. The use of animal models to decipher physiological and neurobiological alterations of anorexia nervosa patients. Front Endocrinol (Lausanne) 2015; 6:68. [PMID: 26042085 PMCID: PMC4436882 DOI: 10.3389/fendo.2015.00068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 04/15/2015] [Indexed: 12/18/2022] Open
Abstract
Extensive studies were performed to decipher the mechanisms regulating feeding due to the worldwide obesity pandemy and its complications. The data obtained might be adapted to another disorder related to alteration of food intake, the restrictive anorexia nervosa. This multifactorial disease with a complex and unknown etiology is considered as an awful eating disorder since the chronic refusal to eat leads to severe, and sometimes, irreversible complications for the whole organism, until death. There is an urgent need to better understand the different aspects of the disease to develop novel approaches complementary to the usual psychological therapies. For this purpose, the use of pertinent animal models becomes a necessity. We present here the various rodent models described in the literature that might be used to dissect central and peripheral mechanisms involved in the adaptation to deficient energy supplies and/or the maintenance of physiological alterations on the long term. Data obtained from the spontaneous or engineered genetic models permit to better apprehend the implication of one signaling system (hormone, neuropeptide, neurotransmitter) in the development of several symptoms observed in anorexia nervosa. As example, mutations in the ghrelin, serotonin, dopamine pathways lead to alterations that mimic the phenotype, but compensatory mechanisms often occur rendering necessary the use of more selective gene strategies. Until now, environmental animal models based on one or several inducing factors like diet restriction, stress, or physical activity mimicked more extensively central and peripheral alterations decribed in anorexia nervosa. They bring significant data on feeding behavior, energy expenditure, and central circuit alterations. Animal models are described and criticized on the basis of the criteria of validity for anorexia nervosa.
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Affiliation(s)
- Mathieu Méquinion
- INSERM UMR-S1172, Development and Plasticity of Postnatal Brain, Lille, France
| | - Christophe Chauveau
- Pathophysiology of Inflammatory Bone Diseases, EA 4490, University of the Littoral Opal Coast, Boulogne sur Mer, France
| | - Odile Viltart
- INSERM UMR-S1172, Early stages of Parkinson diseases, University Lille 1, Lille, France
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Chitravanshi VC, Kawabe K, Sapru HN. GABA and glycine receptors in the nucleus ambiguus mediate tachycardia elicited by chemical stimulation of the hypothalamic arcuate nucleus. Am J Physiol Heart Circ Physiol 2015; 309:H174-84. [PMID: 25957221 DOI: 10.1152/ajpheart.00801.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 05/01/2015] [Indexed: 02/07/2023]
Abstract
We have previously reported that stimulation of the hypothalamic arcuate nucleus (ARCN) by microinjections of N-methyl-d-aspartic acid (NMDA) elicits tachycardia, which is partially mediated via inhibition of vagal inputs to the heart. The neuronal pools and neurotransmitters in them mediating tachycardia elicited from the ARCN have not been identified. We tested the hypothesis that the tachycardia elicited from the ARCN may be mediated by inhibitory neurotransmitters in the nucleus ambiguus (nAmb). Experiments were done in urethane-anesthetized, artificially ventilated, male Wistar rats. In separate groups of rats, unilateral and bilateral microinjections of muscimol (1 mM), gabazine (0.01 mM), and strychnine (0.5 mM) into the nAmb significantly attenuated tachycardia elicited by unilateral microinjections of NMDA (10 mM) into the ARCN. Histological examination of the brains showed that the microinjections sites were within the targeted nuclei. Retrograde anatomic tracing from the nAmb revealed direct bilateral projections from the ARCN and hypothalamic paraventricular nucleus to the nAmb. The results of the present study suggest that tachycardia elicited by stimulation of the ARCN by microinjections of NMDA is mediated via GABAA and glycine receptors located in the nAmb.
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Affiliation(s)
- Vineet C Chitravanshi
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Kazumi Kawabe
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Hreday N Sapru
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey
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Xu LJ, Liu TT, He ZG, Hong QX, Xiang HB. Hypothesis: CeM-RVLM circuits may be implicated in sudden unexpected death in epilepsy by melanocortinergic-sympathetic signaling. Epilepsy Behav 2015; 45:124-7. [PMID: 25819799 DOI: 10.1016/j.yebeh.2015.02.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Li-Jun Xu
- Department of Cardiothroracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 Hubei, PR China
| | - Tao-Tao Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China
| | - Zhi-Gang He
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China
| | - Qing-Xiong Hong
- Department of Anesthesiology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou 510120, PR China.
| | - Hong-Bing Xiang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
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58
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Karami Kheirabad M, Namavar Jahromi B, Tamadon A, Ramezani A, Ahmadloo S, Sabet Sarvestan F, Koohi-Hosseinabadi O. Expression of Melanocortin-4 Receptor mRNA in Male Rat Hypothalamus During Chronic Stress. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2015; 4:182-7. [PMID: 26629487 PMCID: PMC4644530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of chronic stress and glucocorticoids receptor antagonist (RU486) on expression of melanocortin 4 receptor (MC4R) mRNA in arcuate nucleus (ARC) of male rats were evaluated. In this study, adult male Sprague Dawley rats were placed into four groups (n=6/group); stress, RU486, stress/RU486, and control groups. In stress group, the rats were restrained, 1 h/day, for 12 days. In RU486 group, the rats were injected RU486 for 12 days. In stress/RU486 group, the rats were injected RU486 1 h before the stress process for 12 days. Relative expression of MC4R mRNA was determined using real-time PCR. Relative expression of MC4R mRNA in the stress group was higher than that of the control rats (P<0.05). Relative expressions of MC4R mRNA were not different between the stress, RU486 and stress/RU486 groups (P>0.05). Chronic restraint stress causes increase in mRNA expression of MC4R in ARC and blockade of glucocorticoid receptors has no effect on this up-regulation.
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Affiliation(s)
| | - Bahia Namavar Jahromi
- Infertility Research Center, Department of OB-GYN, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Amin Tamadon
- Transgenic Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Corresponding author: Transgenic Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. E-mail:
| | - Amin Ramezani
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technology, Shiraz University of Medical Sciences, Shiraz, Iran.,Institute of Cancer Research, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Somayeh Ahmadloo
- Infertility Research Center, Department of OB-GYN, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Fatemeh Sabet Sarvestan
- Infertility Research Center, Department of OB-GYN, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
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Liu B, Feng J, Wang JH. Protein kinase C is essential for kainate-induced anxiety-related behavior and glutamatergic synapse upregulation in prelimbic cortex. CNS Neurosci Ther 2014; 20:982-90. [PMID: 25180671 DOI: 10.1111/cns.12313] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/21/2014] [Accepted: 07/21/2014] [Indexed: 12/24/2022] Open
Abstract
AIM Anxiety is one of common mood disorders, in which the deficit of serotonergic and GABAergic synaptic functions in the amygdala and prefrontal cortex is believed to be involved. The pathological changes at the glutamatergic synapses and neurons in these brain regions as well as their underlying mechanisms remain elusive, which we aim to investigate. METHODS An agonist of kainate-type glutamate receptors, kainic acid, was applied to induce anxiety-related behaviors. The morphology and functions of glutamatergic synapses in the prelimbic region of mouse prefrontal cortex were analyzed using cellular imaging and electrophysiology. RESULTS After kainate-induced anxiety is onset, the signal transmission at the glutamatergic synapses is upregulated, and the dendritic spine heads are enlarged. In terms of the molecular mechanisms, the upregulated synaptic plasticity is associated with the expression of more protein kinase C (PKC) in the dendritic spines. Chelerythrine, a PKC inhibitor, reverses kainate-induced anxiety and anxiety-related glutamatergic synapse upregulation. CONCLUSION The activation of glutamatergic kainate-type receptors leads to anxiety-related behaviors and glutamatergic synapse upregulation through protein kinase C in the prelimbic region of the mouse prefrontal cortex.
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Affiliation(s)
- Bei Liu
- College of Life Science, University of Science and Technology of China, Hefei, China; State Key Laboratory, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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60
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Serova LI, Laukova M, Alaluf LG, Sabban EL. Blockage of melanocortin-4 receptors by intranasal HS014 attenuates single prolonged stress-triggered changes in several brain regions. J Neurochem 2014; 131:825-35. [PMID: 25087915 DOI: 10.1111/jnc.12847] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/22/2014] [Accepted: 07/29/2014] [Indexed: 12/27/2022]
Abstract
Melanocortin receptor four (MC4R) is implicated in regulation of stress-related functions. We previously demonstrated that intranasal infusion of MC4R antagonist HS014, shortly before single prolonged stress (SPS) animal model of post-traumatic stress disorder, lessened the development of anxiety- and depression-like behavior depending on the dose. Here, we evaluated effects of HS014 on SPS-elicited changes in hypothalamic-pituitary-adrenal axis and expression of several genes of interest in mediobasal hypothalamus, hippocampus, and locus coeruleus. Rats were given intranasal infusion of HS014 (3.5 ng or 100 μg) and 30 min later subjected to SPS stressors. Short-term responses of HS014 rats in comparison with vehicle-treated, evident 30 min following SPS stressors, included smaller rise in plasma corticosterone (100 μg HS014), absence of induction of corticotrophin-releasing hormone mRNA in mediobasal hypothalamus and of mRNA for tyrosine hydroxylase and dopamine-β hydroxylase in locus coeruleus. Long-term responses found 7 days after SPS stressors, included lower induction corticotrophin-releasing hormone mRNA levels in the mediobasal hypothalamus without effect on mRNAs for the glucocorticoid receptor (GR) and FK506-binding protein 51 (FKBP5), a component of GR co-chaperone complex; and no induction of GR protein in ventral hippocampus. Thus, antagonism of MC4R prior to SPS attenuates development of several abnormalities in gene expression in regions implicated in post-traumatic stress disorder. Blockade of brain melanocortine receptor 4 (MC4R) with intranasal infusion of the MC4R antagonist HS014 to rats prior to single prolonged stress (SPS) leads to faster termination of stress responses (30 min later) and prevents or attenuates SPS-triggered abnormal gene expression related to post-traumatic stress disorder (7 days later). Targeting of brain MC4R is a promising strategy to protect HPA axis, LC-NE (locus coeruleus-norepinephrine) systems and hippocampus from overstimulation.
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Affiliation(s)
- Lidia I Serova
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, USA
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61
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Balsevich G, Uribe A, Wagner KV, Hartmann J, Santarelli S, Labermaier C, Schmidt MV. Interplay between diet-induced obesity and chronic stress in mice: potential role of FKBP51. J Endocrinol 2014; 222:15-26. [PMID: 24781256 DOI: 10.1530/joe-14-0129] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
While it is known that stress promotes obesity, the effects of stress within an obesogenic context are not so clear and molecular targets at the interface remain elusive. The FK506-binding protein 51 (FKBP51, gene: Fkbp5) has been identified as a target gene implicated in the development of stress-related psychiatric disorders and is a possible candidate for involvement in stress and metabolic regulation. The aims of the current study are to investigate the interaction between chronic stress and an obesogenic context and to additionally examine whether FKBP51 is involved in this interaction. For this purpose, male C57BL/6 mice were exposed to a high-fat diet for 8 weeks before being challenged with chronic social defeat stress. Herein, we demonstrate that chronic stress induces hypophagia and weight loss, ultimately improving features arising from an obesogenic context, including glucose tolerance and levels of insulin and leptin. We show that Fkbp5 expression is responsive to diet and stress in the hypothalamus and hippocampus respectively. Furthermore, under basal conditions, higher levels of hypothalamic Fkbp5 expression were related to increased body weight gain. Our data indicate that Fkbp5 may represent a novel target in metabolic regulation.
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Affiliation(s)
- Georgia Balsevich
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
| | - Andres Uribe
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
| | - Klaus V Wagner
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
| | - Jakob Hartmann
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
| | - Sara Santarelli
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
| | | | - Mathias V Schmidt
- Max Planck Institute of PsychiatryKraepelinstr. 2-10, 80804 Munich, Germany
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Ryan KK, Mul JD, Clemmensen C, Egan AE, Begg DP, Halcomb K, Seeley RJ, Herman JP, Ulrich-Lai YM. Loss of melanocortin-4 receptor function attenuates HPA responses to psychological stress. Psychoneuroendocrinology 2014; 42:98-105. [PMID: 24636506 PMCID: PMC4120841 DOI: 10.1016/j.psyneuen.2014.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 12/27/2022]
Abstract
The melanocortin 4 receptor (MC4R), well-known for its role in the regulation of energy balance, is widely expressed in stress-regulatory brain regions, including the paraventricular nucleus of the hypothalamus (PVH) and the medial amygdala (MeA). In agreement with this, MC4R has been implicated in hypothalamic-pituitary-adrenocortical axis (HPA) regulation. The present work investigated the role of chronic Mc4r function to modulate basal HPA axis tone and to facilitate acute HPA responses to psychological stress, using a novel rat model with Mc4r loss-of-function. In this study, adult male rats were placed into 3 groups (n=15/group) according to genotype [wild-type (WT); heterozygous mutant (HET); and homozygous mutant (HOM)]. Basal (pre-stress) plasma adrenocorticotropic hormone (ACTH) and corticosterone were measured in the AM and PM, and the HPA axis response to restraint was assessed in the AM. Rats were perfused at 2h after restraint to assess the effect of loss of MC4R on stress-induced c-Fos immunolabeling in stress-regulatory brain regions. We find that basal (non-stress) AM and PM plasma ACTH and corticosterone showed a normal diurnal rhythm that was not altered according to genotype. Consistent with this, adrenal and thymus weights were unaffected by genotype. However, the plasma ACTH and corticosterone responses to restraint were significantly reduced by loss of MC4R function. Likewise, stress-induced c-Fos immunolabeling in both PVH and MeA was significantly reduced by loss of Mc4r function. These results support the hypothesis that endogenous MC4R signaling contributes to the HPA axis response to stress. Because MC4R plays a critical role in the regulation of energy balance, the present work suggests that it may also serve as an important communication link between brain metabolic and stress systems.
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Affiliation(s)
- Karen K. Ryan
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati, Cincinnati OH, USA
| | - Joram D. Mul
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati, Cincinnati OH, USA
| | - Christoffer Clemmensen
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati, Cincinnati OH, USA,Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Ann E. Egan
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati OH, USA
| | - Denovan P. Begg
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati OH, USA
| | - Kristen Halcomb
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati OH, USA
| | - Randy J. Seeley
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati, Cincinnati OH, USA
| | - James P. Herman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati OH, USA
| | - Yvonne M. Ulrich-Lai
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati OH, USA
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Caruso V, Lagerström MC, Olszewski PK, Fredriksson R, Schiöth HB. Synaptic changes induced by melanocortin signalling. Nat Rev Neurosci 2014; 15:98-110. [PMID: 24588018 DOI: 10.1038/nrn3657] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The melanocortin system has a well-established role in the regulation of energy homeostasis, but there is growing evidence of its involvement in memory, nociception, mood disorders and addiction. In this Review, we focus on the role of the melanocortin 4 receptor and provide an integrative view of the molecular mechanisms that lead to melanocortin-induced changes in synaptic plasticity within these diverse physiological systems. We also highlight the importance of melanocortin peptides and receptors in chronic pain syndromes, memory impairments, depression and drug abuse, and the possibility of targeting them for therapeutic purposes.
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Intermittent feeding schedules--behavioural consequences and potential clinical significance. Nutrients 2014; 6:985-1002. [PMID: 24599157 PMCID: PMC3967173 DOI: 10.3390/nu6030985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 02/06/2014] [Accepted: 02/17/2014] [Indexed: 11/26/2022] Open
Abstract
Food availability and associated sensory cues such as olfaction are known to trigger a range of hormonal and behavioural responses. When food availability is predictable these physiological and behavioural responses can become entrained to set times and occur in anticipation of food rather than being dependent on the food-related cues. Here we summarise the range of physiological and behavioural responses to food when the time of its availability is unpredictable, and consider the potential to manipulate feeding patterns for benefit in metabolic and mental health.
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65
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Abstract
Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion.
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66
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Bazhan N, Yakovleva T, Kazantseva A, Makarova E. Exaggerated anorexigenic response to restraint stress in Ay mice is associated with elevated CRFR2 mRNA expression in the hypothalamus. Physiol Behav 2013; 120:19-25. [DOI: 10.1016/j.physbeh.2013.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 03/29/2013] [Accepted: 06/27/2013] [Indexed: 11/26/2022]
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67
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Lerma-Cabrera JM, Carvajal F, Alcaraz-Iborra M, de la Fuente L, Navarro M, Thiele TE, Cubero I. Adolescent binge-like ethanol exposure reduces basal α-MSH expression in the hypothalamus and the amygdala of adult rats. Pharmacol Biochem Behav 2013; 110:66-74. [PMID: 23792540 DOI: 10.1016/j.pbb.2013.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 06/03/2013] [Accepted: 06/09/2013] [Indexed: 01/31/2023]
Abstract
Melanocortins (MC) are central peptides that have been implicated in the modulation of ethanol consumption. There is experimental evidence that chronic ethanol exposure reduces α-MSH expression in the limbic and hypothalamic brain regions and alters central pro-opiomelanocortin (POMC) mRNA activity in adult rats. Adolescence is a critical developmental period of high vulnerability in which ethanol exposure alters corticotropin releasing factor, neuropeptide Y, substance P and neurokinin neuropeptide activities, all of which have key roles in ethanol consumption. Given the involvement of MC and the endogenous inverse agonist AgRP in ethanol drinking, here we evaluate whether a binge-like pattern of ethanol treatment during adolescence has a relevant impact on basal and/or ethanol-stimulated α-MSH and AgRP activities during adulthood. To this end, adolescent Sprague-Dawley rats (beginning at PND25) were pre-treated with either saline (SP group) or binge-like ethanol exposure (BEP group; 3.0 g/kg given in intraperitoneal (i.p.) injections) of one injection per day over two consecutive days, followed by 2 days without injections, repeated for a total of 8 injections. Following 25 ethanol-free days, we evaluated α-MSH and AgRP immunoreactivity (IR) in the limbic and hypothalamic nuclei of adult rats (PND63) in response to ethanol (1.5 or 3.0 g/kgi.p.) and saline. We found that binge-like ethanol exposure during adolescence significantly reduced basal α-MSH IR in the central nucleus of the amygdala (CeA), the arcuate nucleus (Arc) and the paraventricular nucleus of the hypothalamus (PVN) during adulthood. Additionally, acute ethanol elicited AgRP IR in the Arc. Rats given the adolescent ethanol treatment required higher doses of ethanol than saline-treated rats to express AgRP. In light of previous evidence that endogenous MC and AgRP regulate ethanol intake through MC-receptor signaling, we speculate that the α-MSH and AgRP disturbances induced by binge-like ethanol exposure during adolescence may contribute to excessive ethanol consumption during adulthood.
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68
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Schwartz GJ, Zeltser LM. Functional organization of neuronal and humoral signals regulating feeding behavior. Annu Rev Nutr 2013; 33:1-21. [PMID: 23642202 DOI: 10.1146/annurev-nutr-071812-161125] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Energy homeostasis--ensuring that energy availability matches energy requirements--is essential for survival. One way that energy balance is achieved is through coordinated action of neural and neuroendocrine feeding circuits, which promote energy intake when energy supply is limited. Feeding behavior engages multiple somatic and visceral tissues distributed throughout the body--contraction of skeletal and smooth muscles in the head and along the upper digestive tract required to consume and digest food, as well as stimulation of endocrine and exocrine secretions from a wide range of organs. Accordingly, neurons that contribute to feeding behaviors are localized to central, peripheral, and enteric nervous systems. To promote energy balance, feeding circuits must be able to identify and respond to energy requirements, as well as the amount of energy available from internal and external sources, and then direct appropriate coordinated responses throughout the body.
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Affiliation(s)
- Gary J Schwartz
- Department of Medicine, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
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69
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Food-intake regulation during stress by the hypothalamo-pituitary-adrenal axis. Brain Res Bull 2013; 95:46-53. [PMID: 23590931 DOI: 10.1016/j.brainresbull.2013.04.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 03/14/2013] [Accepted: 04/08/2013] [Indexed: 12/20/2022]
Abstract
The prevalence of obesity is increasing worldwide with serious consequences such as diabetes mellitus type 2 and cardiovascular diseases. Emotional stress is considered to be one of the main reasons of obesity development in humans. However, there are some contradictory results, which should be addressed. First of all stress induces anorexia, but not overeating in laboratory animals. Glucocorticoids, the effector molecules of the hypothalamo-pituitary-adrenocortical (HPA) axis stimulate and stress inhibits food intake. It is also not clear if stress is diabetogenic or an antidiabetogenic factor. The review will discusses these issues and the involvement of the whole HPA axis and its separate molecules (glucocorticoids, adrenocorticotropin, corticotropin-releasing hormone) in food intake regulation under stress.
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Melanocortin-4 receptor in the medial amygdala regulates emotional stress-induced anxiety-like behaviour, anorexia and corticosterone secretion. Int J Neuropsychopharmacol 2013; 16:105-20. [PMID: 22176700 PMCID: PMC3708461 DOI: 10.1017/s146114571100174x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The central melanocortin system has been implicated in emotional stress-induced anxiety, anorexia and activation of the hypothalamo-pituitary-adrenal (HPA) axis. However, the underlying neural substrates have not been identified. The medial amygdala (MeA) is highly sensitive to emotional stress and expresses high levels of the melanocortin-4 receptor (MC4R). This study investigated the effects of activation and blockade of MC4R in the MeA on anxiety-like behaviour, food intake and corticosterone secretion. We demonstrate that MC4R-expressing neurons in the MeA were activated by acute restraint stress, as indicated by induction of c-fos mRNA expression. Infusion of a selective MC4R agonist into the MeA elicited anxiogenic-like effects in the elevated plus-maze test and decreased food intake. In contrast, local MeA infusion of SHU 9119, a MC4R antagonist, blocked restraint stress-induced anxiogenic and anorectic effects. Moreover, plasma corticosterone levels were increased by intra-MeA infusion of the MC4R agonist under non-stressed conditions and restraint stress-induced elevation of plasma corticosterone levels was attenuated by pretreatment with SHU 9119 in the MeA. Thus, stimulating MC4R in the MeA induces stress-like anxiogenic and anorectic effects as well as activation of the HPA axis, whereas antagonizing MC4R in this region blocks such effects induced by restraint stress. Together, our results implicate MC4R signalling in the MeA in behavioural and endocrine responses to stress.
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71
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Bispectral index dynamics during propofol hypnosis is similar in red-haired and dark-haired subjects. Anesth Analg 2013; 116:319-26. [PMID: 23302977 DOI: 10.1213/ane.0b013e31827533b4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND We have previously shown that red hair is associated with increased desflurane requirement for immobility, compared with dark hair. The effect of red hair on IV anesthetic requirement remains unknown. We tested the hypothesis that the propofol concentration in the effect site associated with half maximal electroencephalogram response, Ce50, is at least 50% higher in subjects with red hair. METHODS We modeled the propofol concentration versus electroencephalogram response relationship using a 2-step approach in 29 healthy dark- and red-haired volunteers receiving a propofol infusion to produce loss of consciousness. Bispectral Index (BIS) was the measure of drug effect. The parameters of a 3-compartment pharmacokinetic model were fit to measured arterial propofol concentrations. The relationship between effect-site propofol concentration (Ce) and BIS was characterized using a sigmoid Emax model. Model performance and accuracy of the estimated parameters were evaluated using accepted metrics and bootstrap resampling. The effect of hair color on the Ce50 for BIS response in the final model was assessed using a threshold of 6.63 (P<0.01) in reduction of -2 log likelihood. The influence of body weight on the model was also assessed. RESULTS The inclusion of hair color as a model covariate did not improve either the pharmacokinetic or the pharmacodynamic model. A separate analysis for the dark- and red-haired subjects estimated a median (95% confidence interval) Ce50 BIS of 2.71 μg/mL (2.28-3.36 μg/mL) and 2.57 μg/mL (1.68-3.60 μg/mL), respectively. Body weight was a significant covariate for the CL1 and V1. CONCLUSIONS Red hair phenotype does not affect the pharmacokinetics or pharmacodynamics of propofol.
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72
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Abstract
A substantial proportion of noncommunicable disease originates in habitual overconsumption of calories, which can lead to weight gain and obesity and attendant comorbidities. At the other end of the spectrum, the consequences of undernutrition in early life and at different stages of adult life can also have major impact on wellbeing and quality of life. To help address some of these issues, greater understanding is required of interactions with food and contemporary diets throughout the life course and at a number of different levels: physiological, metabolic, psychological, and emotional. Here we review the current literature on the effects of dietary manipulation on anxiety-like behaviour. This evidence, assembled from study of preclinical models of diet challenge from gestation to adult life, supports a role for diet in the important connections between psychology, physiology, and behaviour. Analogous processes in the human population in our current obesogenic environment are likely to contribute to individual and societal challenges in this area.
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Affiliation(s)
- Michelle Murphy
- Rowett Institute of Nutrition and Health, University of Aberdeen, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK
- *Michelle Murphy:
| | - Julian G. Mercer
- Rowett Institute of Nutrition and Health, University of Aberdeen, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK
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73
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Kawabe T, Kawabe K, Sapru HN. Effect of barodenervation on cardiovascular responses elicited from the hypothalamic arcuate nucleus of the rat. PLoS One 2012; 7:e53111. [PMID: 23300873 PMCID: PMC3531379 DOI: 10.1371/journal.pone.0053111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/23/2012] [Indexed: 02/07/2023] Open
Abstract
We have previously reported that chemical stimulation of the hypothalamic arcuate nucleus (ARCN) in the rat elicited increases as well as decreases in blood pressure (BP) and sympathetic nerve activity (SNA). The type of response elicited from the ARCN (i.e., increase or decrease in BP and SNA) depended on the level of baroreceptor activity which, in turn, was determined by baseline BP in rats with intact baroreceptors. Based on this information, it was hypothesized that baroreceptor unloading may play a role in the type of response elicited from the ARCN. Therefore, the effect of barodenervation on the ARCN-induced cardiovascular and sympathetic responses and the neurotransmitters in the hypothalamic paraventricular nucleus (PVN) mediating the excitatory responses elicited from the ARCN were investigated in urethane-anesthetized adult male Wistar rats. Bilateral barodenervation converted decreases in mean arterial pressure (MAP) and greater splanchnic nerve activity (GSNA) elicited by chemical stimulation of the ARCN with microinjections of N-methyl-D-aspartic acid to increases in MAP and GSNA and exaggerated the increases in heart rate (HR). Combined microinjections of NBQX and D-AP7 (ionotropic glutamate receptor antagonists) into the PVN in barodenervated rats converted increases in MAP and GSNA elicited by the ARCN stimulation to decreases in MAP and GSNA and attenuated increases in HR. Microinjections of SHU9119 (a melanocortin 3/4 receptor antagonist) into the PVN in barodenervated rats attenuated increases in MAP, GSNA and HR elicited by the ARCN stimulation. ARCN neurons projecting to the PVN were immunoreactive for proopiomelanocortin, alpha-melanocyte stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH). It was concluded that increases in MAP and GSNA and exaggeration of tachycardia elicited by the ARCN stimulation in barodenervated rats may be mediated via release of alpha-MSH and/or ACTH and glutamate from the ARCN neurons projecting to the PVN.
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Affiliation(s)
- Tetsuya Kawabe
- Department of Neurological Surgery, University of Medicine and Dentistry of New Jersey- New Jersey Medical School, Newark, New Jersey, United States of America
| | - Kazumi Kawabe
- Department of Neurological Surgery, University of Medicine and Dentistry of New Jersey- New Jersey Medical School, Newark, New Jersey, United States of America
| | - Hreday N. Sapru
- Department of Neurological Surgery, University of Medicine and Dentistry of New Jersey- New Jersey Medical School, Newark, New Jersey, United States of America
- * E-mail:
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74
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Abstract
A recent paper in Nature (Lim et al., 2012) describes the effects of melanocortin receptors in the nucleus accumbens. The studies connect a hypothalamic peptide system with brain reward centers and show effects on specific neuronal populations and behavioral components of mood.
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Affiliation(s)
- Benjamin B Land
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
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75
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Zeltser LM, Seeley RJ, Tschöp MH. Synaptic plasticity in neuronal circuits regulating energy balance. Nat Neurosci 2012; 15:1336-42. [DOI: 10.1038/nn.3219] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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76
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Region- and sex-specific changes in CART mRNA in rat hypothalamic nuclei induced by forced swim stress. Brain Res 2012; 1479:62-71. [PMID: 22960117 DOI: 10.1016/j.brainres.2012.08.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 01/22/2023]
Abstract
Cocaine and amphetamine regulated transcript (CART) mRNA and peptides are highly expressed in the paraventricular (PVN), dorsomedial (DMH) and arcuate (ARC) nuclei of the hypothalamus. It has been suggested that these nuclei regulate the hypothalamic-pituitary-adrenal (HPA) axis, autonomic nervous system activity, and feeding behavior. Our previous studies showed that forced swim stress augmented CART peptide expression significantly in whole hypothalamus of male rats. In another study, forced swim stress increased the number of CART-immunoreactive cells in female PVN, whereas no effect was observed in male PVN or in the ARC nucleus of either sex. In the present study, we evaluated the effect of forced swim stress on CART mRNA expression in PVN, DMH and ARC nuclei in both male and female rats. Twelve male (stressed and controls, n=6 each) and 12 female (stressed and controls, n=6 each) Sprague-Dawley rats were used. Control animals were only handled, whereas forced swim stress procedure was applied to the stressed groups. Brains were dissected and brain sections containing PVN, DMH and ARC nuclei were prepared. CART mRNA levels were determined by in situ hybridization. In male rats, forced swim stress upregulated CART mRNA expression in DMH and downregulated it in the ARC. In female rats, forced swim stress increased CART mRNA expression in PVN and DMH, whereas a decrease was observed in the ARC nucleus. Our results show that forced swim stress elicits region- and sex-specific changes in CART mRNA expression in rat hypothalamus that may help in explaining some of the effects of stress.
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77
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Lim BK, Huang KW, Grueter BA, Rothwell PE, Malenka RC. Anhedonia requires MC4R-mediated synaptic adaptations in nucleus accumbens. Nature 2012; 487:183-9. [PMID: 22785313 PMCID: PMC3397405 DOI: 10.1038/nature11160] [Citation(s) in RCA: 282] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 04/25/2012] [Indexed: 12/12/2022]
Abstract
Chronic stress is a strong diathesis for depression in humans and is used to generate animal models of depression. It commonly leads to several major symptoms of depression including dysregulated feeding behavior, anhedonia, and behavioral despair. Although hypotheses defining the neural pathophysiology of depression have been proposed, the critical synaptic adaptations in key brain circuits that mediate stress-induced depressive symptoms remain poorly understood. Here we show that chronic stress decreases the strength of excitatory synapses on D1 dopamine receptor-expressing nucleus accumbens medium spiny neurons due to activation of melanocortin 4 receptors (MC4Rs). Stress-elicited increases in behavioral measurements of anhedonia, but not increases in measurements of behavioral despair, are prevented by blocking these MC4R-mediated synaptic changes in vivo. These results establish that stress-elicited anhedonia requires a neuropeptide-triggered, cell type-specific synaptic adaptation in the nucleus accumbens and that distinct circuit adaptations mediate other major symptoms of stress-elicited depression.
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Affiliation(s)
- Byung Kook Lim
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, California 94305, USA
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78
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Garza JC, Guo M, Zhang W, Lu XY. Leptin restores adult hippocampal neurogenesis in a chronic unpredictable stress model of depression and reverses glucocorticoid-induced inhibition of GSK-3β/β-catenin signaling. Mol Psychiatry 2012; 17:790-808. [PMID: 22182938 PMCID: PMC3368076 DOI: 10.1038/mp.2011.161] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Stress and glucocorticoid stress hormones inhibit neurogenesis, whereas antidepressants increase neurogenesis and block stress-induced decrease in neurogenesis. Our previous studies have shown that leptin, an adipocyte-derived hormone with antidepressant-like properties, promotes baseline neurogenesis in the adult hippocampus. This study aimed to determine whether leptin is able to restore suppression of neurogenesis in a rat chronic unpredictable stress (CUS) model of depression. Chronic treatment with leptin reversed the CUS-induced reduction of hippocampal neurogenesis and depression-like behaviors. Leptin treatment elicited a delayed long-lasting antidepressant-like effect in the forced swim behavioral despair test, and this effect was blocked by ablation of neurogenesis with X-irradiation. The functional isoform of the leptin receptor, LepRb, and the glucocorticoid receptor (GR) were colocalized in hippocampal neural stem/progenitor cells in vivo and in vitro. Leptin treatment reversed the GR agonist dexamethasone (DEX)-induced reduction of proliferation of cultured neural stem/progenitor cells from adult hippocampus. Further mechanistic analysis revealed that leptin and DEX converged on glycogen synthase kinase-3β (GSK-3β) and β-catenin. While DEX decreased Ser9 phosphorylation and increased Tyr216 phosphorylation of GSK-3β, leptin increased Ser9 phosphorylation and attenuated the effects of DEX at both Ser9 and Tyr216 phosphorylation sites of GSK-3β. Moreover, leptin increased total level and nuclear translocation of β-catenin, a primary substrate of GSK-3β and a key regulator in controlling hippocampal neural progenitor cell proliferation, and reversed the inhibitory effects of DEX on β-catenin. Taken together, our results suggest that adult neurogenesis is involved in the delayed long-lasting antidepressant-like behavioral effects of leptin, and leptin treatment counteracts chronic stress and glucocorticoid-induced suppression of hippocampal neurogenesis via activating the GSK-3β/β-catenin signaling pathway.
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Affiliation(s)
- Jacob C. Garza
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Ming Guo
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Wei Zhang
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Xin-Yun Lu
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229,Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229,To whom correspondence should be addressed: Xin-Yun Lu, M.D., Ph.D., Department of Pharmacology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, Phone: 210-567-0803, Fax : 210-567-4303,:
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79
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Maniam J, Morris MJ. The link between stress and feeding behaviour. Neuropharmacology 2012; 63:97-110. [PMID: 22710442 DOI: 10.1016/j.neuropharm.2012.04.017] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 04/11/2012] [Accepted: 04/20/2012] [Indexed: 02/06/2023]
Abstract
Exposure to stress is inevitable, and it may occur, to varying degrees, at different phases throughout the lifespan. The impact of stress experienced in later life has been well documented as many populations in modern society experience increasing socio-economic demands. The effects of stress early in life are less well known, partly as the impact of an early exposure may be difficult to quantify, however emerging evidence shows it can impact later in life. One of the major impacts of stress besides changes in psychosocial behaviour is altered feeding responses. The system that regulates stress responses, the hypothalamo-pituitary-adrenal axis, also regulates feeding responses because the neural circuits that regulate food intake converge on the paraventricular nucleus, which contains corticotrophin releasing hormone (CRH), and urocortin containing neurons. In other words the systems that control food intake and stress responses share the same anatomy and thus each system can influence each other in eliciting a response. Stress is known to alter feeding responses in a bidirectional pattern, with both increases and decreases in intake observed. Stress-induced bidirectional feeding responses underline the complex mechanisms and multiple contributing factors, including the levels of glucocorticoids (dependent on the severity of a stressor), the interaction between glucocorticoids and feeding related neuropeptides such as neuropeptide Y (NPY), alpha-melanocyte stimulating hormone (α-MSH), agouti-related protein (AgRP), melanocortins and their receptors, CRH, urocortin and peripheral signals (leptin, insulin and ghrelin). This review discusses the neuropeptides that regulate feeding behaviour and how their function can be altered through cross-talk with hormones and neuropeptides that also regulate the hypothalamo-pituitary-adrenal axis. In addition, long-term stress induced alterations in feeding behaviour, and changes in gene expression of neuropeptides regulating stress and food intake through epigenetic modifications will be discussed. This article is part of a Special Issue entitled 'SI: Central Control of Food Intake'.
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Affiliation(s)
- Jayanthi Maniam
- Pharmacology, School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia
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80
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Wang K, Zhang R, He F, Lin LB, Xiang XH, Ping XJ, Han JS, Zhao GP, Zhang QH, Cui CL. Electroacupuncture frequency-related transcriptional response in rat arcuate nucleus revealed region-distinctive changes in response to low- and high-frequency electroacupuncture. J Neurosci Res 2012; 90:1464-73. [PMID: 22411682 DOI: 10.1002/jnr.23028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 12/07/2011] [Accepted: 12/16/2011] [Indexed: 02/05/2023]
Abstract
Electroacupuncture (EA) has been clinically applied for treating different medical conditions, such as pain, strain, and immune diseases. Low- and high-frequency EAs have distinct therapeutic effects in clinical practice and experimental studies. However, the molecular mechanism of this difference remains obscure. The arcuate nucleus (Arc) is a critical region of the hypothalamus and is responsible for the effect of EA stimulation to remote acupoints. Gene expression profiling provides a powerful tool with which to explore the basis of physiopathological responses to external stimulus. In this study, using cDNA microarray, we investigated gene expressions in the rat Arc region induced by low-frequency (2-Hz) and high-frequency (100-Hz) EAs to two remote acupoints, zusanli (ST36) and sanyinjiao (SP6). We have found that more genes were differentially regulated by 2-Hz EA than 100-Hz EA (154 vs. 66 regulated genes/ESTs) in Arc, especially those related to neurogenesis, which was confirmed by qRT-PCR. These results demonstrate that the expression level of genes in the Arc region could be effectively regulated by low-frequency EA, compared with high-frequency EA, helping to uncover the mechanisms of the therapeutic effects of the low-frequency EA. Our results also indicate different-frequency EAs are spatially specific.
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Affiliation(s)
- Ke Wang
- National Engineering Research Center for Biochip at Shanghai, Shanghai 201203, People’s Republic of China
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81
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Guo M, Lu Y, Garza JC, Li Y, Chua SC, Zhang W, Lu B, Lu XY. Forebrain glutamatergic neurons mediate leptin action on depression-like behaviors and synaptic depression. Transl Psychiatry 2012; 2:e83. [PMID: 22408745 PMCID: PMC3298113 DOI: 10.1038/tp.2012.9] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The glutamatergic system has been implicated in the pathophysiology of depression and the mechanism of action of antidepressants. Leptin, an adipocyte-derived hormone, has antidepressant-like properties. However, the functional role of leptin receptor (Lepr) signaling in glutamatergic neurons remains to be elucidated. In this study, we generated conditional knockout mice in which the long form of Lepr was ablated selectively in glutamatergic neurons located in the forebrain structures, including the hippocampus and prefrontal cortex (Lepr cKO). Lepr cKO mice exhibit normal growth and body weight. Behavioral characterization of Lepr cKO mice reveals depression-like behavioral deficits, including anhedonia, behavioral despair, enhanced learned helplessness and social withdrawal, with no evident signs of anxiety. In addition, loss of Lepr in forebrain glutamatergic neurons facilitates NMDA-induced hippocampal long-term synaptic depression (LTD), whereas conventional LTD or long-term potentiation (LTP) was not affected. The facilitated LTD induction requires activation of the GluN2B subunit as it was completely blocked by a selective GluN2B antagonist. Moreover, Lepr cKO mice are highly sensitive to the antidepressant-like behavioral effects of the GluN2B antagonist but resistant to leptin. These results support important roles for Lepr signaling in glutamatergic neurons in regulating depression-related behaviors and modulating excitatory synaptic strength, suggesting a possible association between synaptic depression and behavioral manifestations of depression.
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Affiliation(s)
- M Guo
- Department of Pharmacology,University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Y Lu
- Genes Cognition and Psychosis Program, NIMH, National Institutes of Health, Bethesda, MD, USA
| | - J C Garza
- Department of Pharmacology,University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Y Li
- Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - S C Chua
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, New York, NY, USA
| | - W Zhang
- Department of Pharmacology,University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - B Lu
- Genes Cognition and Psychosis Program, NIMH, National Institutes of Health, Bethesda, MD, USA,GlaxoSmithKline, R&D China, Shanghai, China,GlaxoSmithKline, R&D China, Shanghai 201203, China E-mail:
| | - X-Y Lu
- Department of Pharmacology,University of Texas Health Science Center at San Antonio, San Antonio, TX, USA,Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA,Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA. E-mail:
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82
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Furmaga H, Sadhu M, Frazer A. Comparison of ΔFosB immunoreactivity induced by vagal nerve stimulation with that caused by pharmacologically diverse antidepressants. J Pharmacol Exp Ther 2012; 341:317-25. [PMID: 22286499 DOI: 10.1124/jpet.111.188953] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Vagal nerve stimulation (VNS) has been approved for treatment of refractory depression. However, there have been few, if any, studies directly comparing the effects produced by VNS in animals with those caused by antidepressants, particularly using clinically relevant stimulation parameters in nonanesthetized animals. In this study, ΔFosB immunohistochemistry was used to evaluate different brain regions activated by long-term administration of VNS. Effects of VNS were compared with those caused by sertraline or desipramine (DMI). Double-labeling of ΔFosB and serotonin was used to determine whether serotonergic neurons in the dorsal raphe nucleus (DRN) were activated by long-term VNS. VNS significantly increased ΔFosB staining in the nucleus tractus solitarius (NTS), parabrachial nucleus (PBN), locus ceruleus (LC), and DRN, as well as in many cortical and limbic areas of brain including those involved in mood and cognition. Most, but not all, of these effects were seen also upon long-term treatments of rats with sertraline or DMI. Some areas where VNS increased ΔFosB (e.g., the NTS, PBN, LC, and peripeduncular nucleus) were not affected significantly by either drug. Sertraline was similar to VNS in causing an increase in the DRN whereas DMI did not. Double-labeling of the DRN with ΔFosB and an antibody for serotonin revealed that only a small percentage of ΔFosB staining in the DRN colocalized with serotonergic neurons. The effects of VNS were somewhat more widespread than those caused by the antidepressants. The increases in ΔFosB produced by VNS were either equivalent to and/or more robust than those seen with antidepressants.
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Affiliation(s)
- Havan Furmaga
- Department of Pharmacology, the University of Texas Health Science Center, San Antonio, Texas, USA
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83
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Forced swim stress elicits region-specific changes in CART expression in the stress axis and stress regulatory brain areas. Brain Res 2012; 1432:56-65. [DOI: 10.1016/j.brainres.2011.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 10/28/2011] [Accepted: 11/03/2011] [Indexed: 11/22/2022]
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84
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Aubin-Horth N, Deschênes M, Cloutier S. Natural variation in the molecular stress network correlates with a behavioural syndrome. Horm Behav 2012; 61:140-6. [PMID: 22155114 DOI: 10.1016/j.yhbeh.2011.11.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 11/22/2011] [Accepted: 11/23/2011] [Indexed: 01/04/2023]
Abstract
In several species, individuals from the same population behave differently from each other. A functional link between variation in personality traits and the stress response has been suggested by studies in artificial selection lines in fish, birds and mammals. The aim of this study was to test whether the expression of genes involved in the stress response co-varies with personality traits in a natural population. Four personality traits, excreted cortisol level and brain expression of six candidate genes (CRF, CRF-R2, POMC1, GR1, GR2, MR) were measured in non-stressed wild-caught threespine sticklebacks (Gasterosteus aculeatus). We found correlations between variation in personality traits and variation in the expression of genes involved in the stress response. Aggressiveness was negatively correlated with cortisol levels. Boldness and aggressiveness formed a behavioural syndrome and were both positively correlated with brain expression of glucocorticoid receptors (GR1 and GR2). Boldness and exploration were positively correlated with expression of POMC1 but not with each other. Our results are compatible with a model that suggests that the aggressiveness-boldness behavioural syndrome could be the consequence of a physiological pleiotropic effect of glucocorticoid receptors, which are involved in the stress response and behaviour variation.
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Affiliation(s)
- Nadia Aubin-Horth
- Département de Biologie et Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada G1V 0A6.
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85
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Yang AM, Ji YK, Su SF, Yang SB, Lu SS, Mi ZY, Yang QZ, Chen Q. Intracerebroventricular administration of neuronostatin induces depression-like effect in forced swim test of mice. Peptides 2011; 32:1948-52. [PMID: 21871935 DOI: 10.1016/j.peptides.2011.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 08/11/2011] [Accepted: 08/11/2011] [Indexed: 11/15/2022]
Abstract
Neuronostatin is a recently discovered endogenous bioactive peptide that is encoded by pro-mRNA of somatostatin. In the present study, we investigated the effect of neuronostatin on mood regulation in the forced swim test of mice. Our results showed intracerebroventricular (i.c.v.) administration of neuronostatin produced an increase in the immobility time, suggesting that neuronostatin induced depression-like effect. In order to rule out the possibility that neuronostatin had increased immobility time by a non-specific reduction in general activity, the effect of neuronostatin on locomotor activity was examined. Neuronostatin had no influence on locomotor activity in mice. In addition, the depression-like effect of neuronostatin was completely reversed by melanocortin 3/4 receptor antagonist SHU9119 or GABAA receptor antagonist bicuculline, but not by opioid receptor antagonist naloxone. These data suggested that the depression-like effect induced by i.c.v. administered neuronostatin was dependent upon the central melanocortin system and GABAA receptor. In conclusion, the results of this study report that neuronostatin induces depression-like effect. These findings reveal that neuronostatin is a new neuropeptide with an important role in regulating depressive behavior.
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Affiliation(s)
- Ai-min Yang
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
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86
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Calvez J, Fromentin G, Nadkarni N, Darcel N, Even P, Tomé D, Ballet N, Chaumontet C. Inhibition of food intake induced by acute stress in rats is due to satiation effects. Physiol Behav 2011; 104:675-83. [PMID: 21787797 DOI: 10.1016/j.physbeh.2011.07.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 07/07/2011] [Accepted: 07/08/2011] [Indexed: 11/17/2022]
Abstract
Acute mild stress induces an inhibition of food intake in rats. In most studies, the cumulative daily food intake is measured but this only provides a quantitative assessment of ingestive behavior. The present study was designed to analyze the reduction in food intake induced by acute stress and to understand which behavioral and central mechanisms are responsible for it. Two different stressors, restraint stress (RS) and forced swimming stress (FSS), were applied acutely to male Wistar rats. We first measured corticosterone and ACTH in plasma samples collected immediately after acute RS and FSS in order to validate our stress models. We measured food intake after RS and FSS and determined meal patterns and behavioral satiety sequences. The expressions of CRF, NPY and POMC in the hypothalamus were also determined immediately after acute RS and FSS. The rise in corticosterone and ACTH levels after both acute RS and FSS validated our models. Furthermore, we showed that acute stress induced a reduction in cumulative food intake which lasted the whole day for RS but only for the first hour after FSS. For both stressors, this stress-induced food intake inhibition was explained by a decrease in meal size and duration, but there was no difference in ingestion speed. The behavioral satiety sequence was preserved after RS and FSS but grooming was markedly increased, which thus competed with, and could reduce, other behaviors, including eating. Lastly, we showed that RS induced an increase in hypothalamic POMC expression. These results suggest that acute stress may affect ingestive behavior by increasing satiation and to some extent by enhancing grooming, and this may be due to stimulation of the hypothalamic POMC neurons.
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Affiliation(s)
- J Calvez
- INRA, UMR914 Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France
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87
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Effect of subchronic administration of tachykinin antagonists on response of guinea-pigs to mild and severe stress. ACTA ACUST UNITED AC 2011; 168:59-68. [DOI: 10.1016/j.regpep.2011.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 02/19/2011] [Accepted: 03/30/2011] [Indexed: 12/23/2022]
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88
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Laalaoui A, Fèvre-Montange M, Ahboucha S, Gamrani H. Proopiomelanocortin in the arcuate nucleus of the rodent Meriones shawi: effects of dehydration. Acta Histochem 2011; 113:369-74. [PMID: 20447683 DOI: 10.1016/j.acthis.2010.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 11/24/2022]
Abstract
Proopiomelanocortin (POMC) is a 36kDa glycoprotein implicated in homeostatic balance. We used in situ hybridization histochemistry coupled with quantitative autoradiography to determine the anatomical distribution of POMC mRNA-expressing neurons in the arcuate nucleus (AN) and to examine the effects of prolonged dehydration on POMC gene expression in a semi-desert rodent, Meriones shawi (Shaw's Jird). In the hypothalamus of control animals, POMC mRNA-expressing neurons were exclusively localized in the AN and they showed a differential distribution and density along its rostro-caudal subdivisions. In dehydrated animals, water deprivation caused a decrease in POMC mRNA labeling in the AN. These results suggest that dehydration stress can induce negative regulation of POMC gene expression in this species. A comparative study of weight variation between control and dehydrated animals showed a weight loss followed by stabilization of weight during prolonged dehydration.
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89
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Cognitive and neural correlates of depression-like behaviour in socially defeated mice: an animal model of depression with cognitive dysfunction. Int J Neuropsychopharmacol 2011; 14:303-17. [PMID: 20735879 PMCID: PMC3432579 DOI: 10.1017/s1461145710000945] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human depression is associated with cognitive deficits. It is critical to have valid animal models in order to investigate mechanisms and treatment strategies for these associated conditions. The goal of this study was to determine the association of cognitive dysfunction with depression-like behaviour in an animal model of depression and investigate the neural circuits underlying the behaviour. Mice that were exposed to social defeat for 14 d developed depression-like behaviour, i.e. anhedonia and social avoidance as indicated by reduced sucrose preference and decreased social interaction. The assessment of cognitive performance of defeated mice demonstrated impaired working memory in the T-maze continuous alternation task and enhanced fear memory in the contextual and cued fear-conditioning tests. In contrast, reference learning and memory in the Morris water maze test were intact in defeated mice. Neuronal activation following chronic social defeat was investigated by c-fosin-situ hybridization. Defeated mice exhibited preferential neural activity in the prefrontal cortex, cingulate cortex, hippocampal formation, septum, amygdala, and hypothalamic nuclei. Taken together, our results suggest that the chronic social defeat mouse model could serve as a valid animal model to study depression with cognitive impairments. The patterns of neuronal activation provide a neural basis for social defeat-induced changes in behaviour.
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90
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Cooper TA, Jenkins SJ, Wojakiewicz L, Kattesh HG, Kojima CJ. Effects of weaning and syndyphalin-33 on expression of melanocortinergic appetite-regulating genes in swine. Domest Anim Endocrinol 2011; 40:165-72. [PMID: 21194875 DOI: 10.1016/j.domaniend.2010.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 11/01/2010] [Accepted: 11/03/2010] [Indexed: 11/26/2022]
Abstract
Syndyphalin-33 (SD-33) increases feed intake in sheep and recently weaned pigs. To assess the effects of SD-33 on hypothalamic gene expression, hypothalami were collected from unweaned pigs (n=19; 21±3 d of age) on day 0. Remaining pigs received an intramuscular injection of 0.5 μmole/kg SD-33 (SD) or saline (VEH) and weaned into individual pens. On days 1, 4, and 7 after weaning, hypothalami were collected from subsets of pigs (n=8 or 9) within each treatment group. Expression of μ-opioid receptor (MOR) was less in SD pigs than in VEH pigs on day 1 and day 4, suggesting down-regulation of the receptor by SD-33. Expression of hypothalamic melanocortin 4 receptor (MC4R) at 1 d after weaning was increased in VEH pigs (but not SD pigs) relative to levels before weaning. Expression of AGRP was not significantly altered by weaning or treatment at 1 d after weaning. At 4 d after weaning, expression of AGRP was greater in SD pigs than in VEH pigs, but at day 7 expression was less in SD pigs than in VEH pigs. A strong positive correlation was noted between expression levels of MOR and MC4R across treatment and time. Treatment with SD-33 appeared to partially abrogate the effects of weaning on expression of two key appetite-regulating genes within 24 h. Effects of SD-33 appear to be mediated at least in part by the μ-opioid receptor and include actions on the melanocortinergic pathway.
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MESH Headings
- Agouti-Related Protein/genetics
- Agouti-Related Protein/physiology
- Animals
- Animals, Suckling
- Eating/physiology
- Female
- Gene Expression Regulation/physiology
- Hypothalamus/physiology
- Male
- Oligopeptides/pharmacology
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/physiology
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/physiology
- Reverse Transcriptase Polymerase Chain Reaction/veterinary
- Swine/physiology
- Weaning
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Affiliation(s)
- T A Cooper
- Department of Animal Science, University of Tennessee, Knoxville, TN 37996, USA
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91
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Yoshida N, Maejima Y, Sedbazar U, Ando A, Kurita H, Damdindorj B, Takano E, Gantulga D, Iwasaki Y, Kurashina T, Onaka T, Dezaki K, Nakata M, Mori M, Yada T. Stressor-responsive central nesfatin-1 activates corticotropin-releasing hormone, noradrenaline and serotonin neurons and evokes hypothalamic-pituitary-adrenal axis. Aging (Albany NY) 2011; 2:775-84. [PMID: 20966530 PMCID: PMC3006020 DOI: 10.18632/aging.100207] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A recently discovered satiety molecule, nesfatin-1, is localized in neurons of the hypothalamus and brain stem and colocalized with stress-related substances, corticotropin-releasing hormone (CRH), oxytocin, proopiomelanocortin, noradrenaline (NA) and 5-hydroxytryptamine (5-HT). Intracerebroventricular (icv) administration of nesfatin-1 produces fear-related behaviors and potentiates stressor-induced increases in plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in rats. These findings suggest a link between nesfatin-1 and stress. In the present study, we aimed to further clarify the neuronal network by which nesfatin-1 could induce stress responses in rats. Restraint stress induced c-Fos expressions in nesfatin-1-immunoreactive neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus, and in the nucleus of solitary tract (NTS), locus coeruleus (LC) and dorsal raphe nucleus (DR) in the brain stem, without altering plasma nesfatin-1 levels. Icv nesfatin-1 induced c-Fos expressions in the PVN, SON, NTS, LC, DR and median raphe nucleus, including PVN-CRH, NTS-NA, LC-NA and DR-5-HT neurons. Nesfatin-1 increased cytosolic Ca2+ concentration in the CRH-immunoreactive neurons isolated from PVN. Icv nesfatin-1 increased plasma ACTH and corticosterone levels. These results indicate that the central nesfatin-1 system is stimulated by stress and activates CRH, NA and 5-HT neurons and hypothalamic-pituitary-adrenal axis, evoking both central and peripheral stress responses.
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Affiliation(s)
- Natsu Yoshida
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
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92
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Chuang JC, Krishnan V, Yu HG, Mason B, Cui H, Wilkinson MB, Zigman JM, Elmquist JK, Nestler EJ, Lutter M, Lutter M. A beta3-adrenergic-leptin-melanocortin circuit regulates behavioral and metabolic changes induced by chronic stress. Biol Psychiatry 2010; 67:1075-82. [PMID: 20060958 PMCID: PMC2868111 DOI: 10.1016/j.biopsych.2009.12.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 11/20/2009] [Accepted: 12/01/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Obesity has been associated with an increased risk of developing several psychiatric illnesses, including major depression and posttraumatic stress disorder. Likewise, these stress-related disturbances are associated with a higher rate of obesity; yet, the neurobiological mechanisms linking obesity and stress remain incompletely understood. METHODS Following exposure to chronic social defeat stress (CSDS), mice were given free access to either regular chow or a Western-style diet high in triglycerides and cholesterol. Comprehensive metabolic and behavioral testing was then conducted. RESULTS Mice subjected to CSDS and then fed a high-fat diet for 30 days display severe behavioral deficits accompanied by redistribution of body fat. Stressed mice have decreased adipose tissue as well as decreased serum leptin levels compared with control mice. Pharmacological inhibition of beta(3)-adrenergic signaling during CSDS normalizes these metabolic abnormalities but worsens behavioral symptoms. Furthermore, mice subjected to CSDS display central leptin resistance including reduced expression of pro-opiomelanocortin in hypothalamus. Administration of a central melanocortin agonist worsens stress-induced behavioral deficits, while mice lacking the melanocortin-4 receptor display attenuated symptoms. CONCLUSIONS These results indicate that chronic signaling through beta(3)-adrenergic receptors during social stress is an adaptive response that improves behavioral function. However, these responses come at the expense of central leptin resistance and melanocortin signaling alterations that contribute to significant and long-lasting metabolic abnormalities.
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Affiliation(s)
- Jen-Chieh Chuang
- Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Vaishnav Krishnan
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Hana G. Yu
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Brittany Mason
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
| | - Huixing Cui
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
,
Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Matthew B. Wilkinson
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029-6574
| | - Jeffrey M. Zigman
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
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Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Joel K. Elmquist
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
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Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
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Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390
| | - Eric J. Nestler
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, 10029-6574
| | - Michael Lutter
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9127
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Department of Internal Medicine (Division of Hypothalamic Research), The University of Texas Southwestern Medical Center, Dallas, TX, 75390
,
To whom correspondence should be addressed.
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93
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Jun DJ, Na KY, Kim W, Kwak D, Kwon EJ, Yoon JH, Yea K, Lee H, Kim J, Suh PG, Ryu SH, Kim KT. Melanocortins induce interleukin 6 gene expression and secretion through melanocortin receptors 2 and 5 in 3T3-L1 adipocytes. J Mol Endocrinol 2010; 44:225-36. [PMID: 20089716 PMCID: PMC3058511 DOI: 10.1677/jme-09-0161] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Interleukin 6 (IL6) is a pleiotropic cytokine that not only affects the immune system, but also plays an active role in many physiological events in various organs. Notably, 35% of systemic IL6 originates from adipose tissues under noninflammatory conditions. Here, we describe a previously unknown function of melanocortins in regulating Il6 gene expression and production in 3T3-L1 adipocytes through membrane receptors which are called melanocortin receptors (MCRs). Of the five MCRs that have been cloned, MC2R and MC5R are expressed during adipocyte differentiation. alpha-Melanocyte-stimulating hormone (alpha-MSH) or ACTH treatment of 3T3-L1 adipocytes induces Il6 gene expression and production in a time- and concentration-dependent manner via various signaling pathways including the protein kinase A, p38 mitogen-activated protein kinase, cJun N-terminal kinase, and IkappaB kinase pathways. Specific inhibition of MC2R and MC5R expression with short interfering Mc2r and Mc5r RNAs significantly attenuated the alpha-MSH-induced increase of intracellular cAMP and both the level of Il6 mRNA and secretion of IL6 in 3T3-L1 adipocytes. Finally, when injected into mouse tail vein, alpha-MSH dramatically increased the Il6 transcript levels in epididymal fat pads. These results suggest that alpha-MSH in addition to ACTH may function as a regulator of inflammation by regulating cytokine production.
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MESH Headings
- 3T3-L1 Cells/cytology
- 3T3-L1 Cells/metabolism
- Adipocytes/cytology
- Adipocytes/metabolism
- Adrenocorticotropic Hormone/metabolism
- Animals
- Cell Differentiation/physiology
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Gene Expression Regulation
- I-kappa B Kinase/metabolism
- Interleukin-6/genetics
- Interleukin-6/metabolism
- JNK Mitogen-Activated Protein Kinases/metabolism
- Male
- Melanocortins/metabolism
- Mice
- Mice, Inbred C57BL
- RNA, Messenger/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptors, Melanocortin/genetics
- Receptors, Melanocortin/metabolism
- Signal Transduction/physiology
- alpha-MSH/metabolism
- p38 Mitogen-Activated Protein Kinases/metabolism
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94
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Cubero I, Navarro M, Carvajal F, Lerma-Cabrera JM, Thiele TE. Ethanol-induced increase of agouti-related protein (AgRP) immunoreactivity in the arcuate nucleus of the hypothalamus of C57BL/6J, but not 129/SvJ, inbred mice. Alcohol Clin Exp Res 2010; 34:693-701. [PMID: 20102560 DOI: 10.1111/j.1530-0277.2009.01138.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND The melanocortin (MC) system is composed of peptides that are cleaved from the polypeptide precursor, pro-opiomelanocortin (POMC). Previous research has shown that MC receptor (MCR) agonists reduce, and MCR antagonists increase, ethanol consumption in rats and mice. Consistently, genetic deletion of the endogenous MCR antagonist, agouti-related protein (AgRP), causes reductions of ethanol-reinforced lever pressing and binge-like ethanol drinking in C57BL/6J mice. Ethanol also has direct effects on the central MC system, as chronic exposure to an ethanol-containing diet causes significant reductions of alpha-melanocyte stimulating hormone (alpha-MSH) immunoreactivity in specific brain regions of Sprague-Dawley rats. Together, these observations suggest that the central MC system modulates neurobiological responses to ethanol. To further characterize the role of the MC system in responses to ethanol, here we compared AgRP and alpha-MSH immunoreactivity in response to an acute injection of saline or ethanol between high ethanol drinking C57BL/6J mice and moderate ethanol drinking 129/SvJ mice. METHODS Mice received an intraperitoneal (i.p.) injection of ethanol (1.5 g/kg or 3.5 g/kg; mixed in 0.9% saline) or an equivolume of 0.9% saline. Two hours after injection, animals were sacrificed and their brains were processed for AgRP and alpha-MSH immunoreactivity. RESULTS Results indicated that acute ethanol administration triggered a dose-dependent increase in AgRP immunoreactivity in the arcuate (ARC) of C57BL/6J mice, an effect that was not evident in the 129/SvJ strain. Although acute administration of ethanol did not influence alpha-MSH immunoreactivity, C57BL/6J mice had significantly greater overall alpha-MSH immunoreactivity in the ARC, dorsomedial, and lateral regions of the hypothalamus relative to the 129/SvJ strain. In contrast, C57BL/6J mice displayed significantly lower alpha-MSH immunoreactivity in the medial amygdala. CONCLUSIONS The results show that acute ethanol exposure has direct effects on endogenous AgRP activity in ethanol preferring C57BL/6J mice. It is suggested that ethanol-induced increases in AgRP may be part of a positive feedback system that stimulates excessive binge-like ethanol drinking in C57BL/6J mice. Inherent differences in alpha-MSH immunoreactivity may contribute to differences in neurobiological responses to ethanol that are characteristically observed between the C57BL/6J and 129/SvJ inbred strains of mice.
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Affiliation(s)
- Inmaculada Cubero
- Department of Neurociencia y Ciencias de la Salud, University of Almería, Almería, Spain
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95
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Wittmann G, Füzesi T, Liposits Z, Lechan RM, Fekete C. Distribution and axonal projections of neurons coexpressing thyrotropin-releasing hormone and urocortin 3 in the rat brain. J Comp Neurol 2010; 517:825-40. [PMID: 19844978 DOI: 10.1002/cne.22180] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Thyrotropin-releasing hormone (TRH) decreases food intake when administered intracerebroventricularly or into the ventromedial hypothalamus. However, it is unknown which population of TRH neurons exerts this anorexigenic function. In the rostral perifornical area, the pattern of TRH-expressing neurons is reminiscent of the distribution of neurons expressing urocortin3 (Ucn3) that also inhibits feeding when injected into the hypothalamic ventromedial nucleus (VMN). Since colocalization of TRH and Ucn3 may help to identify feeding-related TRH neurons, the putative coexpression of the two peptides was examined using fluorescent in situ hybridization combined with immunofluorescence. Almost all (95.5 +/- 0.2%) Ucn3-immunoreactive neurons in the perifornical area expressed pro-TRH mRNA, while 50.2 +/- 1.6% Ucn3 neurons were double-labeled in the bed nucleus of the stria terminalis (BNST). Only a few Ucn3/pro-TRH neurons were found outside these two areas. The distribution of axons containing both Ucn3 and TRH was examined by dual immunofluorescence. Ucn3/TRH fibers heavily innervated the VMN. In addition, high densities of double-labeled axons were observed in the lateral septal nucleus, posterior division of the BNST, medial amygdaloid nucleus, amygdalohippocampal area, and ventral hippocampus, forebrain areas associated with psychological stress and anxiety. We conclude that Ucn3 and TRH are coexpressed in a discrete, continuous population of neurons in the perifornical area and BNST, making Ucn3 a neurochemical marker to define a distinct subset of TRH neurons. The distribution of their axons suggests that Ucn3/TRH neurons may coordinate feeding and behavioral responses to stressful stimuli.
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Affiliation(s)
- Gábor Wittmann
- Department of Endocrine Neurobiology, Hungarian Academy of Sciences, Budapest, Hungary
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96
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Gautron L, Layé S. Neurobiology of inflammation-associated anorexia. Front Neurosci 2010; 3:59. [PMID: 20582290 PMCID: PMC2858622 DOI: 10.3389/neuro.23.003.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 12/16/2009] [Indexed: 12/23/2022] Open
Abstract
Compelling data demonstrate that inflammation-associated anorexia directly results from the action of pro-inflammatory factors, primarily cytokines and prostaglandins E2, on the nervous system. For instance, the aforementioned pro-inflammatory factors can stimulate the activity of peripheral sensory neurons, and induce their own de novo synthesis and release into the brain parenchyma and cerebrospinal fluid. Ultimately, it results in the mobilization of a specific neural circuit that shuts down appetite. The present article describes the different cell groups and neurotransmitters involved in inflammation-associated anorexia and examines how they interact with neural systems regulating feeding such as the melanocortin system. A better understanding of the neurobiological mechanisms underlying inflammation-associated anorexia will help to develop appetite stimulants for cancer and AIDS patients.
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Affiliation(s)
- Laurent Gautron
- The University of Texas Southwestern Medical Center Dallas, TX, USA
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97
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Genetic variations associated with red hair color and fear of dental pain, anxiety regarding dental care and avoidance of dental care. J Am Dent Assoc 2009; 140:896-905. [PMID: 19571053 DOI: 10.14219/jada.archive.2009.0283] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Red hair color is caused by variants of the melanocortin-1 receptor (MC1R) gene. People with naturally red hair are resistant to subcutaneous local anesthetics and, therefore, may experience increased anxiety regarding dental care. The authors tested the hypothesis that having natural red hair color, a MC1R gene variant or both could predict a patient's experiencing dental care-related anxiety and dental care avoidance. METHODS The authors enrolled 144 participants (67 natural red-haired and 77 dark-haired) aged 18 to 41 years in a cross-sectional observational study. Participants completed validated survey instruments designed to measure general and dental care-specific anxiety, fear of dental pain and previous dental care avoidance. The authors genotyped participants' blood samples to detect variants associated with natural red hair color. RESULTS Eighty-five participants had MC1R gene variants (65 of the 67 red-haired participants and 20 of the 77 dark-haired participants) (P < .001). Participants with MC1R gene variants reported significantly more dental care-related anxiety and fear of dental pain than did participants with no MC1R gene variants. They were more than twice as likely to avoid dental care as were the participants with no MC1R gene variants, even after the authors controlled for general trait anxiety and sex. CONCLUSION Dental care-related anxiety, fear of dental pain and avoidance of dental care may be influenced by genetic variations. CLINICAL IMPLICATIONS Dentists should evaluate all patients, but especially those with naturally red hair, for dental care-related anxiety and use appropriate modalities to manage the patients' anxiety.
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98
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Yosten GLC, Samson WK. Nesfatin-1 exerts cardiovascular actions in brain: possible interaction with the central melanocortin system. Am J Physiol Regul Integr Comp Physiol 2009; 297:R330-6. [PMID: 19474390 DOI: 10.1152/ajpregu.90867.2008] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nesfatin-1 is a recently discovered hypothalamic peptide that was shown to suppress food intake through a melanocortin-3/4 receptor-dependent mechanism. Since nesfatin-1 mRNA is detected in the paraventricular nucleus of the hypothalamus, and because many peptides that alter food intake also influence cardiovascular function, we tested the ability of centrally administered nesfatin-1 to affect mean arterial pressure (MAP) in conscious, freely moving rats. Significant increases in MAP were observed following intracerebroventricular administration of nesfatin-1. Pretreatment with either the melanocortin-3/4 receptor antagonist, SHU9119 (intracerebroventricular), or the alpha-adrenergic antagonist, phentolamine (intra-arterial), abrogated the rise in MAP induced by nesfatin-1, indicating that nesfatin-1 may interact with the central melanocortin system to increase sympathetic nerve activity and lead to an increase in MAP. Thus we have identified a novel action of nesfatin-1, in addition to its anorexigenic effects, to stimulate autonomic nervous system activity.
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Affiliation(s)
- Gina L C Yosten
- Saint Louis Univ., Dept. of Pharmacological and Physiological Science, 1402 S. Grand Blvd., St. Louis, MO 63104, USA.
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99
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Chitravanshi VC, Bhatt S, Sapru HN. Microinjections of alpha-melanocyte stimulating hormone into the nucleus ambiguus of the rat elicit vagally mediated bradycardia. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1402-11. [PMID: 19297540 DOI: 10.1152/ajpregu.90978.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurons that immunostain for alpha-melanocyte stimulating hormone (alpha-MSH) have been identified in the nucleus ambiguus (nAmb). The presence of mRNA for melanocortin type 4 receptors (MC4Rs) has also been reported in this nucleus. On the basis of this information, it was hypothesized that activation of MC4Rs in the nAmb may play a role in the regulation of cardiac function. This hypothesis was tested in urethane-anesthetized, artificially ventilated, adult male Wistar rats. Microinjections (30 nl) of alpha-MSH (0.1, 0.2, 0.4, 0.8, and 1.2 mM) into the nAmb of anesthetized rats elicited decreases in heart rate (HR; 1.3 +/- 0.6, 3 +/- 1, 11 +/- 2, 46.3 +/- 3, and 43.3 +/- 7 bpm, respectively) and no changes in mean arterial pressure (MAP). Maximum decreases in HR were elicited by 0.8 mM concentration of alpha-MSH. Bradycardic responses to alpha-MSH were similar in unanesthetized midcollicular decerebrate rats. Microinjections of artificial cerebrospinal fluid (30 nl) into the nAmb did not elicit a HR response. Bilateral vagotomy completely abolished alpha-MSH-induced bradycardia. The decreases in HR elicited by alpha-MSH (0.8 mM) were completely blocked by a selective MC4R antagonist. Direct application of alpha-MSH on the nAmb neurons increased their firing, which was blocked by prior applications of the MC4R antagonist. Microinjections of the MC4R antagonist into the nAmb did not alter reflex bradycardic responses elicited by intravenous infusions of phenylephrine, suggesting that MC4Rs did not play a role in mediating the parasympathetic component of baroreflex-induced bradycardia. These results indicated that alpha-MSH microinjections into the nAmb exert excitatory effects on parasympathetic preganglionic nAmb neurons via MC4Rs, leading to bradycardic responses.
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Affiliation(s)
- Vineet C Chitravanshi
- Department of Neurological Surgery, University of Medicine and Dentistry-New Jersey Medical School, Newark, N.J. 07103, USA
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100
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Sinno MH, Do Rego JC, Coëffier M, Bole-Feysot C, Ducrotté P, Gilbert D, Tron F, Costentin J, Hökfelt T, Déchelotte P, Fetissov SO. Regulation of feeding and anxiety by alpha-MSH reactive autoantibodies. Psychoneuroendocrinology 2009; 34:140-9. [PMID: 18842346 DOI: 10.1016/j.psyneuen.2008.08.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 08/25/2008] [Accepted: 08/25/2008] [Indexed: 01/08/2023]
Abstract
alpha-Melanocyte-stimulating hormone (alpha-MSH) is a stress-related neuropeptide involved in the regulation of motivated behavior, appetite and emotion including stimulation of satiety and anxiety. Although autoantibodies (autoAbs) reactive with alpha-MSH have been identified in human subjects and in rats, it remained unknown if these autoAbs are involved in the regulation of feeding and anxiety and if their production is related to stress. Here we show that repeated exposure of rats to anxiolytic mild stress by handling increases the levels and affinity of alpha-MSH reactive IgG autoAbs and that these changes are associated with adaptive feeding and anxiety responses during exposure of rats to a strong stress by food restriction. Importantly, an increase in affinity of alpha-MSH reactive autoAbs was associated with changes of their functional roles from stimulation to inhibition of alpha-MSH-mediated behavioural responses, suggesting that these autoAbs can be a carrier or a neutralizing molecule of alpha-MSH peptide, respectively. Using a model of passive transfer into the brain, we show that alpha-MSH autoAbs affinity purified from blood of rats exposed to repeated mild stress, but not from control rats, are able to increase acutely food intake, suppress anxiety and modify gene expression of hypothalamic neuropeptides in naïve rats. These data provide the first evidence that autoAbs reactive with alpha-MSH are involved in the physiological regulation of feeding and mood, supporting a further role of the immune system in the control of motivated behavior and adaptation to stress.
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Affiliation(s)
- Maria Hamze Sinno
- Digestive System & Nutrition Laboratory (ADEN EA4311), Institute of Biomedical Research, Rouen University & Hospital, IFR23, 76183 Rouen, France
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