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Jaramillo JCM, Aitken CM, Lawrence AJ, Ryan PJ. Oxytocin-receptor-expressing neurons in the lateral parabrachial nucleus activate widespread brain regions predominantly involved in fluid satiation. J Chem Neuroanat 2024; 137:102403. [PMID: 38452468 DOI: 10.1016/j.jchemneu.2024.102403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024]
Abstract
Fluid satiation is an important signal and aspect of body fluid homeostasis. Oxytocin-receptor-expressing neurons (OxtrPBN) in the dorsolateral subdivision of the lateral parabrachial nucleus (dl LPBN) are key neurons which regulate fluid satiation. In the present study, we investigated brain regions activated by stimulation of OxtrPBN neurons in order to better characterise the fluid satiation neurocircuitry in mice. Chemogenetic activation of OxtrPBN neurons increased Fos expression (a proxy marker for neuronal activation) in known fluid-regulating brain nuclei, as well as other regions that have unclear links to fluid regulation and which are likely involved in regulating other functions such as arousal and stress relief. In addition, we analysed and compared Fos expression patterns between chemogenetically-activated fluid satiation and physiological-induced fluid satiation. Both models of fluid satiation activated similar brain regions, suggesting that the chemogenetic model of stimulating OxtrPBN neurons is a relevant model of physiological fluid satiation. A deeper understanding of this neural circuit may lead to novel molecular targets and creation of therapeutic agents to treat fluid-related disorders.
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Affiliation(s)
- Janine C M Jaramillo
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Connor M Aitken
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Philip J Ryan
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.
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2
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Skinner JA, Campbell EJ, Dayas CV, Garg ML, Burrows TL. The relationship between oxytocin, dietary intake and feeding: A systematic review and meta-analysis of studies in mice and rats. Front Neuroendocrinol 2019; 52:65-78. [PMID: 30315826 DOI: 10.1016/j.yfrne.2018.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/13/2018] [Accepted: 09/28/2018] [Indexed: 01/11/2023]
Abstract
The neuropeptide oxytocin has been associated with food intake and feeding behaviour. This systematic review aimed to investigate the impact of oxytocin on dietary intake and feeding behaviour in rodent studies. Six electronic databases were searched to identify published studies to April 2018. Preclinical studies in mice and rats were included if they reported: (1) a dietary measure (i.e. food or nutrient and/or behaviour (2) an oxytocin measure, and (3) relationship between the two measures. A total of 75 articles (n = 246 experiments) were included, and study quality appraised. The majority of studies were carried out in males (87%). The top three oxytocin outcomes assessed were: exogenous oxytocin administration (n = 126), oxytocin-receptor antagonist administration (n = 46) and oxytocin gene deletion (n = 29). Meta-analysis of exogenous studies in mice (3 studies, n = 43 comparisons) and rats (n = 8 studies, n = 82 comparisons) showed an overall decrease in food intake with maximum effect shown at 2 h post-administration.
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Affiliation(s)
- Janelle A Skinner
- Nutrition and Dietetics, School of Health Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia; Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Erin J Campbell
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Victoria 3010, Australia.
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Manohar L Garg
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Tracy L Burrows
- Nutrition and Dietetics, School of Health Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia; Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW 2308, Australia.
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3
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Ryan PJ, Ross SI, Campos CA, Derkach VA, Palmiter RD. Oxytocin-receptor-expressing neurons in the parabrachial nucleus regulate fluid intake. Nat Neurosci 2017; 20:1722-1733. [PMID: 29184212 PMCID: PMC5705772 DOI: 10.1038/s41593-017-0014-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 09/17/2017] [Indexed: 02/08/2023]
Abstract
Brain regions that regulate fluid satiation are not well characterized, yet are essential for understanding fluid homeostasis. We found that oxytocin-receptor-expressing neurons in the parabrachial nucleus of mice (OxtrPBN neurons) are key regulators of fluid satiation. Chemogenetic activation of OxtrPBN neurons robustly suppressed noncaloric fluid intake, but did not decrease food intake after fasting or salt intake following salt depletion; inactivation increased saline intake after dehydration and hypertonic saline injection. Under physiological conditions, OxtrPBN neurons were activated by fluid satiation and hypertonic saline injection. OxtrPBN neurons were directly innervated by oxytocin neurons in the paraventricular hypothalamus (OxtPVH neurons), which mildly attenuated fluid intake. Activation of neurons in the nucleus of the solitary tract substantially suppressed fluid intake and activated OxtrPBN neurons. Our results suggest that OxtrPBN neurons act as a key node in the fluid satiation neurocircuitry, which acts to decrease water and/or saline intake to prevent or attenuate hypervolemia and hypernatremia. The authors show that oxytocin-receptor-expressing neurons in the parabrachial nucleus are key regulators of fluid homeostasis that suppress fluid intake when activated, but do not decrease food intake after fasting or salt intake after salt depletion.
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Affiliation(s)
- Philip J Ryan
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA. .,Department of Biochemistry, University of Washington, Seattle, Washington, USA. .,The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.
| | - Silvano I Ross
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA.,Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Carlos A Campos
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA.,Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Victor A Derkach
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA.,Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Richard D Palmiter
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, USA. .,Department of Biochemistry, University of Washington, Seattle, Washington, USA.
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4
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The Role of the Oxytocin/Arginine Vasopressin System in Animal Models of Autism Spectrum Disorder. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2017; 224:135-158. [DOI: 10.1007/978-3-319-52498-6_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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5
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Erdman SE, Poutahidis T. Microbes and Oxytocin: Benefits for Host Physiology and Behavior. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 131:91-126. [PMID: 27793228 DOI: 10.1016/bs.irn.2016.07.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is now understood that gut bacteria exert effects beyond the local boundaries of the gastrointestinal tract to include distant tissues and overall health. Prototype probiotic bacterium Lactobacillus reuteri has been found to upregulate hormone oxytocin and systemic immune responses to achieve a wide array of health benefits involving wound healing, mental health, metabolism, and myoskeletal maintenance. Together these display that the gut microbiome and host animal interact via immune-endocrine-brain signaling networks. Such findings provide novel therapeutic strategies to stimulate powerful homeostatic pathways and genetic programs, stemming from the coevolution of mammals and their microbiome.
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Affiliation(s)
- S E Erdman
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States; Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | - T Poutahidis
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States; Aristotle University of Thessaloniki, Thessaloniki, Greece
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Yoshimura M, Uezono Y, Ueta Y. Anorexia in human and experimental animal models: physiological aspects related to neuropeptides. J Physiol Sci 2015; 65:385-95. [PMID: 26123258 PMCID: PMC10717229 DOI: 10.1007/s12576-015-0386-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/16/2015] [Indexed: 01/20/2023]
Abstract
Anorexia, a loss of appetite for food, can be caused by various physiological and pathophysiological conditions. In this review, firstly, clinical aspects of anorexia nervosa are summarized in brief. Secondly, hypothalamic neuropeptides responsible for feeding regulation in each hypothalamic nucleus are discussed. Finally, three different types of anorexigenic animal models; dehydration-induced anorexia, cisplatin-induced anorexia and cancer anorexia-cachexia, are introduced. In conclusion, hypothalamic neuropeptides may give us novel insight to understand and find effective therapeutics strategy essential for various kinds of anorexia.
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Affiliation(s)
- Mitsuhiro Yoshimura
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555 Japan
| | - Yasuhito Uezono
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, 104-0045 Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555 Japan
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7
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de Souza Mecawi A, Ruginsk SG, Elias LLK, Varanda WA, Antunes‐Rodrigues J. Neuroendocrine Regulation of Hydromineral Homeostasis. Compr Physiol 2015; 5:1465-516. [DOI: 10.1002/cphy.c140031] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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8
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Yi KJ, So KH, Hata Y, Suzuki Y, Kato D, Watanabe K, Aso H, Kasahara Y, Nishimori K, Chen C, Katoh K, Roh SG. The regulation of oxytocin receptor gene expression during adipogenesis. J Neuroendocrinol 2015; 27:335-42. [PMID: 25702774 DOI: 10.1111/jne.12268] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 01/27/2015] [Accepted: 02/17/2015] [Indexed: 01/02/2023]
Abstract
Although it has been reported that oxytocin stimulates lipolysis in adipocytes, changes in the expression of oxytocin receptor (OTR) mRNA in adipogenesis are still unknown. The present study aimed to investigate the expression of OTR mRNA during adipocyte differentiation and fat accumulation in adipocytes. OTR mRNA was highly expressed in adipocytes prepared from mouse adipose tissues compared to stromal-vascular cells. OTR mRNA expression was increased during the adipocyte differentiation of 3T3-L1 cells. OTR expression levels were higher in subcutaneous and epididymal adipose tissues of 14-week-old male mice compared to 7-week-old male mice. Levels of OTR mRNA expression were higher in adipose tissues at four different sites of mice fed a high-fat diet than in those of mice fed a normal diet. The OTR expression level was also increased by refeeding for 4 h after fasting for 16 h. Oxytocin significantly induced lipolysis in 3T3-L1 adipocytes. In conclusion, a new regulatory mechanism is demonstrated for oxytocin to control the differentiation and fat accumulation in adipocytes via activation of OTR as a part of the hypothalamic-pituitary-adipose axis.
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Affiliation(s)
- K J Yi
- Laboratory of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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9
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Greenwood MP, Mecawi AS, Hoe SZ, Mustafa MR, Johnson KR, Al-Mahmoud GA, Elias LLK, Paton JFR, Antunes-Rodrigues J, Gainer H, Murphy D, Hindmarch CCT. A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus. Am J Physiol Regul Integr Comp Physiol 2015; 308:R559-68. [PMID: 25632023 DOI: 10.1152/ajpregu.00444.2014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/21/2015] [Indexed: 01/16/2023]
Abstract
Salt loading (SL) and water deprivation (WD) are experimental challenges that are often used to study the osmotic circuitry of the brain. Central to this circuit is the supraoptic nucleus (SON) of the hypothalamus, which is responsible for the biosynthesis of the hormones, arginine vasopressin (AVP) and oxytocin (OXT), and their transport to terminals that reside in the posterior lobe of the pituitary. On osmotic challenge evoked by a change in blood volume or osmolality, the SON undergoes a function-related plasticity that creates an environment that allows for an appropriate hormone response. Here, we have described the impact of SL and WD compared with euhydrated (EU) controls in terms of drinking and eating behavior, body weight, and recorded physiological data including circulating hormone data and plasma and urine osmolality. We have also used microarrays to profile the transcriptome of the SON following SL and remined data from the SON that describes the transcriptome response to WD. From a list of 2,783 commonly regulated transcripts, we selected 20 genes for validation by qPCR. All of the 9 genes that have already been described as expressed or regulated in the SON by osmotic stimuli were confirmed in our models. Of the 11 novel genes, 5 were successfully validated while 6 were false discoveries.
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Affiliation(s)
| | - Andre S Mecawi
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - See Ziau Hoe
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Rais Mustafa
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kory R Johnson
- Clinical Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Ghada A Al-Mahmoud
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Al Tarfa, Doha, Qatar
| | - Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Julian F R Paton
- School of Physiology and Pharmacology, University Walk, Bristol, United Kingdom; and
| | - Jose Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom; Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Charles C T Hindmarch
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom; Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia;
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10
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Einfeld SL, Smith E, McGregor IS, Steinbeck K, Taffe J, Rice LJ, Horstead SK, Rogers N, Hodge MA, Guastella AJ. A double-blind randomized controlled trial of oxytocin nasal spray in Prader Willi syndrome. Am J Med Genet A 2014; 164A:2232-9. [DOI: 10.1002/ajmg.a.36653] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/28/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Stewart L. Einfeld
- Centre for Disability Research and Policy; University of Sydney; Sydney New South Wales Australia
- Faculty of Health Sciences; University of Sydney; Sydney New South Wales Australia
- Brain and Mind Research Institute; University of Sydney; Sydney New South Wales Australia
| | - Ellie Smith
- Children's Hospital at Westmead Clinical School; University of Sydney; Sydney New South Wales Australia
| | - Iain S. McGregor
- School of Psychology; The University of Sydney; Sydney New South Wales Australia
| | - Kate Steinbeck
- The Discipline of Pediatrics and Child Health University of Sydney; Sydney New South Wales Australia
- The Academic Department of Adolescent Medicine; The Children's Hospital at Westmead; Sydney New South Wales Australia
| | - John Taffe
- Centre for Developmental Psychiatry and Psychology; Department of Psychiatry; School of Clinical Sciences; Monash University; Melbourne Victoria Australia
| | - Lauren J. Rice
- Faculty of Health Sciences; University of Sydney; Sydney New South Wales Australia
- Brain and Mind Research Institute; University of Sydney; Sydney New South Wales Australia
| | - Siân K. Horstead
- Faculty of Health Sciences; University of Sydney; Sydney New South Wales Australia
- Brain and Mind Research Institute; University of Sydney; Sydney New South Wales Australia
| | - Naomi Rogers
- Concord Centre for Cardiometabolic Health in Psychosis, Concord Medical School; University of Sydney; Sydney New South Wales Australia
| | - M. Antoinette Hodge
- Children's Hospital at Westmead Clinical School; University of Sydney; Sydney New South Wales Australia
| | - Adam J. Guastella
- Brain and Mind Research Institute; University of Sydney; Sydney New South Wales Australia
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11
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Gene Network Analysis in Amygdala following Taste Aversion Learning in Rats. NEUROSCIENCE JOURNAL 2013; 2013:739764. [PMID: 26317099 PMCID: PMC4437262 DOI: 10.1155/2013/739764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 02/28/2013] [Accepted: 04/02/2013] [Indexed: 11/17/2022]
Abstract
Conditioned taste aversion (CTA) is an adaptive behavior that benefits survival of animals including humans and also serves as a powerful model to study the neural mechanisms of learning. Memory formation is a necessary component of CTA learning and involves neural processing and regulation of gene expression in the amygdala. Many studies have been focused on the identification of intracellular signaling cascades involved in CTA, but not late responsive genes underlying the long-lasting behavioral plasticity. In this study, we explored in silico experiments to identify persistent changes in gene expression associated with CTA in rats. We used oligonucleotide microarrays to identify 248 genes in the amygdala regulated by CTA. Pathway Studio and IPA software analyses showed that the differentially expressed genes in the amygdala fall in diverse functional categories such as behavior, psychological disorders, nervous system development and function, and cell-to-cell signaling. Conditioned taste aversion is a complex behavioral trait which involves association of visceral and taste inputs, consolidation of taste and visceral information, memory formation, retrieval of stored information, and extinction phase. In silico analysis of differentially expressed genes is therefore necessary to manipulate specific phase/stage of CTA to understand the molecular insight.
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12
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González-Mariscal G, Lemus AC, Vega-Gonzalez A, Aguilar-Roblero R. Litter Size Determines Circadian Periodicity of Nursing in Rabbits. Chronobiol Int 2013; 30:711-8. [DOI: 10.3109/07420528.2013.784769] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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McKinley MJ. Adaptive appetites for salted and unsalted food in rats: differential effects of sodium depletion, DOCA, and dehydration. Am J Physiol Regul Integr Comp Physiol 2013; 304:R1149-60. [PMID: 23594615 DOI: 10.1152/ajpregu.00481.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Most ingested sodium is contained in food. The aim was to investigate whether sodium depletion, dehydration, or DOCA alters intakes of salted and unsalted foods by rats given choices of two foods: salted (0.2-0.5% Na) and unsalted food containing either similar or different other dietary components. Diuretic-induced (furosemide or acetazolamide, two treatments on successive days) sodium depletion always caused pronounced falls in intake of unsalted food within 24 h, continuing at least another 2 days (e.g., 20.9 ± 1.6 pretreatment to 14.8 ± 1.2, 10.6 ± 1.5, and 14.3 ± 1.3 g/day for 3 days of depletion). Intake and preference for salted food increased after 24-72 h (e.g., 6.5 ± 1.2 pretreatment to 7.1 ± 1.1, 16.4 ± 2.3, and 17.0 ± 1.5 g/day at 1, 2, and 3 days of depletion). Valsartan (10 mg/day) blocked the increased intake of salted food but not the reduced intake of unsalted food. DOCA (2 mg/day) caused equivalent increase and decrease in intakes of salted and unsalted food, respectively. Water-deprived rats reduced intake (e.g., 14.2 ± 3.1 to 3.2 ± 2.0 g/day) of and preference for salted food (e.g., 56 ± 13% to 21 ± 11%) after 2 days of dehydration but did not consistently reduce intake of unsalted food. Total food ingested/day fell in both sodium-depleted and dehydrated rats. Rats regulate intakes of different foods to balance sodium needs, osmoregulatory homeostasis, and energy requirements. Reduced appetite for unsalted food may be a homeostatic response to sodium depletion, which together with subsequent generation of appetite for salted food, drives animals to ingest sodium-containing food, thereby restoring sodium balance.
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Affiliation(s)
- M J McKinley
- Florey Neuroscience Institutes of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia.
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14
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Ho JM, Blevins JE. Coming full circle: contributions of central and peripheral oxytocin actions to energy balance. Endocrinology 2013; 154:589-96. [PMID: 23270805 PMCID: PMC3548187 DOI: 10.1210/en.2012-1751] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The neuropeptide oxytocin has emerged as an important anorexigen in the regulation of energy balance. Its effects on food intake have largely been attributed to limiting meal size through interactions in key regulatory brain regions such as the hypothalamus and hindbrain. Pharmacologic and pair-feeding studies indicate that its ability to reduce body mass extends beyond that of food intake, affecting multiple factors that determine energy balance such as energy expenditure, lipolysis, and glucose regulation. Systemic administration of oxytocin recapitulates many of its effects when administered centrally, raising the questions of whether and to what extent circulating oxytocin contributes to energy regulation. Its therapeutic potential to treat metabolic conditions remains to be determined, but data from diet-induced and genetically obese rodent models as well as application of oxytocin in humans in other areas of research have revealed promising results thus far.
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Affiliation(s)
- Jacqueline M Ho
- Veterans Affairs Puget Sound Health Care System, 1660 South Columbian Way, Seattle, WA 98108, USA.
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15
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Wu Z, Xu Y, Zhu Y, Sutton AK, Zhao R, Lowell BB, Olson DP, Tong Q. An obligate role of oxytocin neurons in diet induced energy expenditure. PLoS One 2012; 7:e45167. [PMID: 23028821 PMCID: PMC3445456 DOI: 10.1371/journal.pone.0045167] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 08/13/2012] [Indexed: 11/25/2022] Open
Abstract
Oxytocin neurons represent one of the major subsets of neurons in the paraventricular hypothalamus (PVH), a critical brain region for energy homeostasis. Despite substantial evidence supporting a role of oxytocin in body weight regulation, it remains controversial whether oxytocin neurons directly regulate body weight homeostasis, feeding or energy expenditure. Pharmacologic doses of oxytocin suppress feeding through a proposed melanocortin responsive projection from the PVH to the hindbrain. In contrast, deficiency in oxytocin or its receptor leads to reduced energy expenditure without feeding abnormalities. To test the physiological function of oxytocin neurons, we specifically ablated oxytocin neurons in adult mice. Our results show that oxytocin neuron ablation in adult animals has no effect on body weight, food intake or energy expenditure on a regular diet. Interestingly, male mice lacking oxytocin neurons are more sensitive to high fat diet-induced obesity due solely to reduced energy expenditure. In addition, despite a normal food intake, these mice exhibit a blunted food intake response to leptin administration. Thus, our study suggests that oxytocin neurons are required to resist the obesity associated with a high fat diet; but their role in feeding is permissive and can be compensated for by redundant pathways.
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Affiliation(s)
- Zhaofei Wu
- Brown Foundation Institute of Molecular Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Yuanzhong Xu
- Brown Foundation Institute of Molecular Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Yaming Zhu
- Brown Foundation Institute of Molecular Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Amy K. Sutton
- Departments of Pediatrics and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rongjie Zhao
- Brown Foundation Institute of Molecular Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Bradford B. Lowell
- Division of Endocrinology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - David P. Olson
- Departments of Pediatrics and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (QT); (DPO)
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Graduate Programs in Biochemistry and Neuroscience of Graduate School of Biomedical Sciences, University of Texas Medical School at Houston, Houston, Texas, United States of America
- * E-mail: (QT); (DPO)
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16
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Vollmer RR, Cai HM, Miedlar JA, Amico JA. Voluntary sodium ingestion in wild-type and oxytocin knockout mice. Clin Exp Hypertens 2012; 35:167-74. [PMID: 22784207 DOI: 10.3109/10641963.2012.702836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oxytocin knockout (OT KO) mice acutely consume inappropriate amounts of sodium following overnight water deprivation suggesting that oxytocinergic neurons inhibit excessive sodium ingestion (Amico JA, Morris M, Vollmer RR. Mice deficient in oxytocin manifest increased saline consumption following overnight fluid deprivation. Am J Physiol - Regul Integr Comp Physiol 2001; 281:R1368-R1373). This study sought to determine whether oxytocin (OT) provides long-term regulation of voluntary sodium ingestion. Wild-type (WT) and oxytocin knockout male mice were provided choices between diets or drinking solutions that differed in their sodium content. Mice were given access for 1 week to two diets, one containing low sodium (0.01% sodium chloride [NaCl]) content and a second containing a normal sodium (1.0% NaCl) content. During the second week, the animals were given a choice between a low sodium diet and a high sodium (8.0% NaCl) diet. In the second week, mice consumed 4 times more sodium; however, there were no differences between WT and OT KO mice. In a second experiment, mice had access to a two-bottle choice of tap water and a 0.5 M NaCl solution made palatable by the addition of a 4.1% Intralipid emulsion. Both genotypes consumed large, but equivalent, volumes of the Intralipid/sodium solution. The ingestion of this sodium-rich solution stimulated thirst and enhanced the intake of water. Thus, the availability of palatable sodium-rich food or solutions can lead to excessive voluntary sodium ingestion. Compared with oxytocin knockout mice, enhanced voluntary ingestion of sodium-rich solid and liquid diets proceeded unimpeded in WT mice. Therefore, OT pathways may not be essential for regulating solute intake in this setting.
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Affiliation(s)
- Regis R Vollmer
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Onaka T, Takayanagi Y, Yoshida M. Roles of oxytocin neurones in the control of stress, energy metabolism, and social behaviour. J Neuroendocrinol 2012; 24:587-98. [PMID: 22353547 DOI: 10.1111/j.1365-2826.2012.02300.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxytocin neurones are activated by stressful stimuli, food intake and social attachment. Activation of oxytocin neurones in response to stressful stimuli or food intake is mediated, at least in part, by noradrenaline/prolactin-releasing peptide (PrRP) neurones in the nucleus tractus solitarius, whereas oxytocin neurones are activated after social stimuli via medial amygdala neurones. Activation of oxytocin neurones induces the release of oxytocin not only from their axon terminals, but also from their dendrites. Oxytocin acts locally where released or diffuses and acts on remote oxytocin receptors widely distributed within the brain, resulting in anxiolytic, anorexic and pro-social actions. The action sites of oxytocin appear to be multiple. Oxytocin shows anxiolytic actions, at least in part, via serotoninergic neurones in the median raphe nucleus, has anorexic actions via pro-opiomelanocortin neurones in the nucleus tractus solitarius and facilitates social recognition via the medial amygdala. Stress, obesity and social isolation are major risk factors for mortality in humans. Thus, the oxytocin-oxytocin receptor system is a therapeutic target for the promotion of human health.
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Affiliation(s)
- T Onaka
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, Shinotsuke-shi, Tochigi-ken, Japan.
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18
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Boyle CN, Lorenzen SM, Compton D, Watts AG. Dehydration-anorexia derives from a reduction in meal size, but not meal number. Physiol Behav 2011; 105:305-14. [PMID: 21854794 DOI: 10.1016/j.physbeh.2011.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 08/02/2011] [Accepted: 08/03/2011] [Indexed: 11/25/2022]
Abstract
The anorexia that results from extended periods of cellular dehydration is an important physiological adaptation that limits the intake of osmolytes from food and helps maintain the integrity of fluid compartments. The ability to experimentally control both the development and reversal of anorexia, together with the understanding of underlying hormonal and neuropeptidergic signals, makes dehydration (DE)-anorexia a powerful model for exploring the interactions of neural networks that stimulate and inhibit food intake. However, it is not known which meal parameters are affected by cellular dehydration to generate anorexia. Here we use continuous and high temporal resolution recording of food and fluid intake, together with a drinking-explicit method of meal pattern analysis to explore which meal parameters are modified during DE-anorexia. We find that the most important factor responsible for DE-anorexia is the failure to maintain feeding behavior once a meal has started, rather than the ability to initiate a meal, which remains virtually intact. This outcome is consistent with increased sensitivity to satiation signals and post-prandial satiety mechanisms. We also find that DE-anorexia significantly disrupts the temporal distribution of meals across the day so that the number of nocturnal meals gradually decreases while diurnal meal number increases. Surprisingly, once DE-anorexia is reversed this temporal redistribution is maintained for at least 4 days after normal food intake has resumed, which may allow increased daily food intake even after normal satiety mechanisms are reinstated. Therefore, DE-anorexia apparently develops from a selective targeting of those neural networks that control meal termination, whereas meal initiation mechanisms remain viable.
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Affiliation(s)
- Christina N Boyle
- The Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089-2520, United States.
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Sinno MH, Coquerel Q, Boukhettala N, Coëffier M, Gallas S, Terashi M, Ibrahim A, Breuillé D, Déchelotte P, Fetissov SO. Chemotherapy-induced anorexia is accompanied by activation of brain pathways signaling dehydration. Physiol Behav 2010; 101:639-48. [DOI: 10.1016/j.physbeh.2010.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/17/2010] [Accepted: 09/22/2010] [Indexed: 02/07/2023]
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Olszewski PK, Klockars A, Schiöth HB, Levine AS. Oxytocin as feeding inhibitor: maintaining homeostasis in consummatory behavior. Pharmacol Biochem Behav 2010; 97:47-54. [PMID: 20595062 DOI: 10.1016/j.pbb.2010.05.026] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 05/12/2010] [Accepted: 05/26/2010] [Indexed: 12/13/2022]
Abstract
Initial studies showed that the anorexigenic peptide oxytocin (OT) regulates gastric motility, responds to stomach distention and to elevated osmolality, and blocks consumption of toxic foods. Most recently, it has been proposed to act as a mediator of general and carbohydrate-specific satiety and regulator of body weight. In the current review, we discuss the function of OT as a homeostatic inhibitor of consumption, capable of mitigating multiple aspects of ingestive behavior and energy metabolism.
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Affiliation(s)
- Pawel K Olszewski
- Minnesota Obesity Center, Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA
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Sawchenko P. Gene dosage effects on hypothalamic visceromotor cell types (commentary on Duplan et al.). Eur J Neurosci 2010; 30:2237-8. [PMID: 20092566 DOI: 10.1111/j.1460-9568.2009.07088.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Paul Sawchenko
- Laboratory of Neuronal Structure and Function, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Duplan SM, Boucher F, Alexandrov L, Michaud JL. Impact of Sim1 gene dosage on the development of the paraventricular and supraoptic nuclei of the hypothalamus. Eur J Neurosci 2009; 30:2239-49. [DOI: 10.1111/j.1460-9568.2009.07028.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lee HJ, Macbeth AH, Pagani JH, Young WS. Oxytocin: the great facilitator of life. Prog Neurobiol 2009; 88:127-51. [PMID: 19482229 DOI: 10.1016/j.pneurobio.2009.04.001] [Citation(s) in RCA: 339] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 02/24/2009] [Accepted: 04/02/2009] [Indexed: 01/01/2023]
Abstract
Oxytocin (Oxt) is a nonapeptide hormone best known for its role in lactation and parturition. Since 1906 when its uterine-contracting properties were described until 50 years later when its sequence was elucidated, research has focused on its peripheral roles in reproduction. Only over the past several decades have researchers focused on what functions Oxt might have in the brain, the subject of this review. Immunohistochemical studies revealed that magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei are the neurons of origin for the Oxt released from the posterior pituitary. Smaller cells in various parts of the brain, as well as release from magnocellular dendrites, provide the Oxt responsible for modulating various behaviors at its only identified receptor. Although Oxt is implicated in a variety of "non-social" behaviors, such as learning, anxiety, feeding and pain perception, it is Oxt's roles in various social behaviors that have come to the fore recently. Oxt is important for social memory and attachment, sexual and maternal behavior, and aggression. Recent work implicates Oxt in human bonding and trust as well. Human disorders characterized by aberrant social interactions, such as autism and schizophrenia, may also involve Oxt expression. Many, if not most, of Oxt's functions, from social interactions (affiliation, aggression) and sexual behavior to eventual parturition, lactation and maternal behavior, may be viewed as specifically facilitating species propagation.
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Affiliation(s)
- Heon-Jin Lee
- Section on Neural Gene Expression, NIMH, NIH, DHHS, Bethesda, MD 20892, USA
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Abstract
The oxytocin receptor has been suggested to be involved in energy metabolism, such as food intake and energy consumption. Here, we demonstrate that oxytocin receptor-deficient (Oxtr-/-) male mice exhibited late-onset obesity with increases in abdominal fat pads and fasting plasma triglycerides. Daily food intake and spontaneous motor activity of Oxtr-/- mice were not significantly different as compared with wild-type mice. In contrast, brown adipose tissue in Oxtr-/- mice contained large lipid droplets and cold-induced thermogenesis was impaired. This study demonstrates that oxytocin receptor plays essential roles in the regulation of energy homeostasis.
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Amico JA, Cai HM, Vollmer RR. Corticosterone release in oxytocin gene deletion mice following exposure to psychogenic versus non-psychogenic stress. Neurosci Lett 2008; 442:262-6. [PMID: 18625285 DOI: 10.1016/j.neulet.2008.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2008] [Revised: 06/30/2008] [Accepted: 07/02/2008] [Indexed: 11/26/2022]
Abstract
Both anxiety-related behavior [J.A. Amico, R.C. Mantella, R.R. Vollmer, X. Li, Anxiety and stress responses in female oxytocin deficient mice, J. Neuroendocrinol. 16 (2004) 1-6; R.C. Mantella, R.R. Vollmer, X. Li, J.A. Amico, Female oxytocin-deficient mice display enhanced anxiety-related behavior, Endocrinology 144 (2003) 2291-2296] and the release of corticosterone following a psychogenic stress such as exposure to platform shaker was greater in female [J.A. Amico, R.C. Mantella, R.R. Vollmer, X. Li, Anxiety and stress responses in female oxytocin deficient mice, J. Neuroendocrinol. 16 (2004) 1-6; R.C. Mantella, R.R. Vollmer, L. Rinaman, X. Li, J.A. Amico, Enhanced corticosterone concentrations and attenuated Fos expression in the medial amygdala of female oxytocin knockout mice exposed to psychogenic stress, Am. J. Physiol. Regul. Integr. Comp. Physiol. 287 (2004) R1494-R1504], but not male [R.C. Mantella, R.R. Vollmer, J.A. Amico, Corticosterone release is heightened in food or water deprived oxytocin deficient male mice, Brain Res. 1058 (2005) 56-61], oxytocin gene deletion (OTKO) mice compared to wild type (WT) cohorts. In the present study we exposed OTKO and WT female mice to another psychogenic stress, inserting a rectal probe to record body temperature followed by brief confinement in a metabolic cage, and measured plasma corticosterone following the stress. OTKO mice released more corticosterone than WT mice (P<0.03) following exposure to this stress. In contrast, if OTKO and WT female and male mice were administered insulin-induced hypoglycemia, an acute physical stress, corticosterone release was not different between genotypes. The absence of central OT signaling pathways in female mice heightens the neuroendocrine (e.g., corticosterone) response to psychogenic stress, but not to the physical stress of insulin-induced hypoglycemia.
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Affiliation(s)
- Janet A Amico
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, United States.
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Kublaoui BM, Gemelli T, Tolson KP, Wang Y, Zinn AR. Oxytocin deficiency mediates hyperphagic obesity of Sim1 haploinsufficient mice. Mol Endocrinol 2008; 22:1723-34. [PMID: 18451093 DOI: 10.1210/me.2008-0067] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Single-minded 1 (Sim1) encodes a transcription factor essential for formation of the hypothalamic paraventricular nucleus (PVN). Sim1 haploinsufficiency is associated with hyperphagic obesity and increased linear growth in humans and mice, similar to the phenotype of melanocortin 4 receptor (Mc4r) mutations. PVN neurons in Sim1(+/-) mice are hyporesponsive to the melanocortin agonist melanotan II. PVN neuropeptides oxytocin (Oxt), TRH and CRH inhibit feeding when administered centrally. Consequently, we hypothesized that altered PVN neuropeptide expression mediates the hyperphagia of Sim1(+/-) mice. To test this hypothesis, we measured hypothalamic expression of PVN neuropeptides in Sim1(+/-) and wild-type mice. Oxt mRNA and peptide were decreased by 80% in Sim1(+/-) mice, whereas TRH, CRH, arginine vasopressin (Avp), and somatostatin mRNAs were decreased by 20-40%. Sim1(+/-) mice also showed abnormal regulation of Oxt but not CRH mRNA in response to feeding state. A selective Mc4r agonist activated PVN Oxt neurons in wild-type mice, supporting involvement of these neurons in melanocortin feeding circuits. To test whether Oxt itself regulates feeding, we measured the effects of central administration of an Oxt receptor antagonist or repeated doses of Oxt on food intake of Sim1(+/-) and wild-type mice. Sim1(+/-) mice were hypersensitive to the orexigenic effect of the Oxt receptor antagonist. Oxt decreased the food intake and weight gain of Sim1(+/-) mice at a dose that did not affect wild-type mice. Our results support the importance of Oxt neurons in feeding regulation and suggest that reduced Oxt neuropeptide is one mechanism mediating the hyperphagic obesity of Sim1(+/-) mice.
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Affiliation(s)
- Bassil M Kublaoui
- Department of Pediatrics, Department of Internal Medicine, McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical School, Dallas, TX 75390-8591, USA.
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Abstract
Recent studies on the regulation of social behaviours by neuropeptides indicate that it is the distribution of peptide receptor expression in particular brain areas that determines the specificity of peptide actions; and that, accordingly, peptides can evoke specific behaviours when administered centrally without temporal or spatial selectivity of administration. The release of neuropeptides at synaptic sites appears irrelevant, and in the brain, some peptides are released mainly from dendrites rather than from nerve endings. Dendritic peptide release can be long lasting, semi-independent of electrical activity, and allows the diffusion of peptides to distant targets. The peptide oxytocin regulates many behaviours; in particular, it inhibits food intake. Centrally, oxytocin is released in large amounts by the dendrites of hypothalamic magnocellular neurons. This mini-review considers the possible involvement of dendritically released oxytocin in the regulation of food intake by its actions on the ventromedial hypothalamus.
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28
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Miedlar JA, Rinaman L, Vollmer RR, Amico JA. Oxytocin gene deletion mice overconsume palatable sucrose solution but not palatable lipid emulsions. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1063-8. [PMID: 17596329 DOI: 10.1152/ajpregu.00228.2007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that oxytocin knockout (OT KO) mice display markedly enhanced intake of sweet and nonsweet carbohydrate solutions compared with intake by wild-type (WT) mice of the same background strain. The present study was conducted to determine whether OT KO mice demonstrate enhanced intake of Intralipid, a palatable lipid emulsion. Male or female mice of both genotypes that were naive to the test solution were given continuous two-bottle access to Intralipid and water with food available ad libitum for 3 days. Throughout the experiment, mice of both genotypes showed a marked preference for Intralipid over water. On the 1st day, OT KO mice displayed twofold greater preference and consumed nearly twice as much Intralipid compared with WT cohorts. However, on subsequent days of exposure, Intralipid preference and intake did not differ between genotypes over a range of lipid concentrations presented in descending or ascending order. Daily and hourly measures of lipid vs. sucrose intake confirmed that OT KO mice consumed more sucrose solution, but not lipid emulsion, than WT mice. During ad libitum access to Intralipid, both genotypes consumed significantly more calories from the emulsion as concentration increased. Both genotypes maintained consistent total daily caloric intake (lipid plus chow) and compensated by decreasing chow intake over the course of the study. These findings, coupled with prior reports from our laboratory, support the view that OT signaling pathways participate in limiting intake of palatable carbohydrate-containing solutions, but do not appear to play a role in limiting intake of Intralipid.
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Affiliation(s)
- J A Miedlar
- Department of Pharmaceutical Sciences, University of Pittsburgh, 540 Salk Hall, Pittsburgh, PA 15261, USA.
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29
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Watts AG, Salter DS, Neuner CM. Neural network interactions and ingestive behavior control during anorexia. Physiol Behav 2007; 91:389-96. [PMID: 17531275 PMCID: PMC2570355 DOI: 10.1016/j.physbeh.2007.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Many models have been proposed over the years to explain how motivated feeding behavior is controlled. One of the most compelling is based on the original concepts of Eliot Stellar whereby sets of interosensory and exterosensory inputs converge on a hypothalamic control network that can either stimulate or inhibit feeding. These inputs arise from information originating in the blood, the viscera, and the telencephalon. In this manner the relative strengths of the hypothalamic stimulatory and inhibitory networks at a particular time dictates how an animal feeds. Anorexia occurs when the balance within the networks consistently favors the restraint of feeding. This article discusses experimental evidence supporting a model whereby the increases in plasma osmolality that result from drinking hypertonic saline activate pathways projecting to neurons in the paraventricular nucleus of the hypothalamus (PVH) and lateral hypothalamic area (LHA). These neurons constitute the hypothalamic controller for ingestive behavior, and receive a set of afferent inputs from regions of the brain that process sensory information that is critical for different aspects of feeding. Important sets of inputs arise in the arcuate nucleus, the hindbrain, and in the telencephalon. Anorexia is generated in dehydrated animals by way of osmosensitive projections to the behavior control neurons in the PVH and LHA, rather than by actions on their afferent inputs.
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Affiliation(s)
- Alan G Watts
- The Neuroscience Research Institute and Neuroscience Graduate Program, USC College, University of Southern California, Los Angeles, CA 90089-2520, United States.
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30
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Abstract
Ingestive behavior is a complex product of distributed central control systems that respond to a diverse array of internal and external sensory stimuli. Relatively little is known regarding the pathways and mechanisms by which relevant signals are conveyed to the neural circuits that ultimately control ingestive motor output. This report summarizes findings regarding the postnatal development of descending hypothalamic inputs to the hindbrain dorsal vagal complex (DVC). Evidence accumulated primarily in rats indicates that descending neural projections from the hypothalamus to the DVC are both structurally and functionally immature at birth. The progressive postnatal maturation of these projections occurs in parallel with newly emerging physiological and behavioral responsiveness to treatments and stimuli that affect food intake in adults. Thus, the postnatal emergence of new feeding controls may reflect the emerging access of these controls to DVC neural circuits.
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Affiliation(s)
- Linda Rinaman
- Department of Neuroscience, 446 Crawford Hall, University of Pittsburgh, PA 15260, USA.
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Ji LL, Gottlieb HB, Penny ML, Fleming T, Toney GM, Cunningham JT. Differential effects of water deprivation and rehydration on Fos and FosB/DeltaFosB staining in the rat brainstem. Exp Neurol 2006; 203:445-56. [PMID: 17027755 DOI: 10.1016/j.expneurol.2006.08.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 08/24/2006] [Accepted: 08/28/2006] [Indexed: 11/27/2022]
Abstract
This study examined the effects of dehydration and rehydration with water on Fos and FosB staining in the brainstem of rats. Male rats were water deprived for 48 h (Dehyd, n=7) or 46 h followed by 2 h access to water (Rehyd, n=7). Controls had ad libitum access to water (Con, n=9). Brainstems were stained for Fos and FosB/DeltaFosB using commercially available antibodies. In the nucleus of the solitary tract (NTS), the number of Fos stained neurons was significantly increased by dehydration and increased further following rehydration (Con 5+/-1; Dehyd 22+/-1; Rehyd 48+/-5). The average number of Fos-positive cells in the parabrachial nucleus (PBN) was significantly increased only by rehydration (Con 12+/-2; Dehyd 6+/-2; Rehyd 51+/-4). The area postrema (AP) showed significant increases in Fos staining after dehydration and rehydration (Fos: Con 4+/-1; Dehyd 28+/-3; Rehyd 24+/-3). In the rostral ventrolateral medulla (RVL), Fos staining significantly increased after dehydration and this effect was reduced by rehydration (Con 3+/-1; Dehyd 21+/-2; Rehyd 12+/-1). In contrast, Fos staining in the caudal ventrolateral medulla (CVL) was not significantly influenced following either dehydration or rehydration with water (Con 4+/-1; Dehyd 4+/-1; Rehyd 5+/-1). FosB/DeltaFosB staining in the NTS, AP, and RVL was comparably increased by dehydration and rehydration. In the PBN and CVL, FosB/DeltaFosB staining was not affected by the treatments. Dehydration and rehydration have regionally specific effects on Fos and FosB/DeltaFosB staining in the brainstem.
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Affiliation(s)
- Lisa L Ji
- Department of Pharmacology, and the Center for Biomedical Neuroscience, UTHSCSA, USA
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32
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Abstract
alpha-Melanocyte-stimulating hormone (alpha-MSH) and oxytocin share remarkable similarities of effects on behaviour in rats; in particular, they both inhibit feeding behaviour and stimulate sexual behaviour. Recently, we showed that alpha-MSH interacts with the magnocellular oxytocin system in the supraoptic nucleus; alpha-MSH induces the release of oxytocin from the dendrites of magnocellular neurones but it inhibits the secretion of oxytocin from their nerve terminals in the posterior pituitary. This effect of alpha-MSH on supraoptic nucleus oxytocin neurones is remarkable for two reasons. First, it illustrates the capacity of magnocellular neurones to differentially regulate peptide release from dendrites and axons and, second, it emphasises the putative role of magnocellular neurones as a major source of central oxytocin release, and as a likely substrate of some oxytocin-mediated behaviours. The ability of peptides to differentially control secretion from different compartments of their targets indicates one way by which peptide signals might have a particularly significant effect on neuronal circuitry. This suggests a possible explanation for the striking way in which some peptides can influence specific, complex behaviours.
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Affiliation(s)
- N Sabatier
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
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33
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Tasker JG. Rapid glucocorticoid actions in the hypothalamus as a mechanism of homeostatic integration. Obesity (Silver Spring) 2006; 14 Suppl 5:259S-265S. [PMID: 17021378 DOI: 10.1038/oby.2006.320] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) is a major integrative site for the control of homeostasis, including energy balance, through coordinated regulation of neuroendocrine and autonomic outputs. However, cross-talk regulation of PVN neuroendocrine and preautonomic systems is poorly understood. The stress response invokes the coordinated control of motor, hormonal, and vegetative systems to establish homeostasis after an environmental perturbation. Elevated stress levels of circulating glucocorticoids give rise to multiple, complex physiological effects. The complexity of the glucocorticoid actions is caused by the wide range of glucocorticoid target tissues and to the broad time scale over which the actions occur. Recent studies have revealed rapid glucocorticoid actions in the hypothalamus that may provide an integrative signal linking stress with the regulation of energy and fluid homeostasis. Glucocorticoids inhibit PVN and supraoptic nucleus neurons by stimulating a rapid synthesis and retrograde release of endocannabinoids, which suppress synaptic excitation through presynaptic CB1 receptor activation. The glucocorticoid-induced endocannabinoid synthesis is mediated apparently by a novel membrane-associated glucocorticoid receptor found in multiple subpopulations of hypothalamic neuroendocrine cells. It may, therefore, represent a mechanism for rapid glucocorticoid control of activity among different neuroendocrine systems to coordinate a global response to stress. In support of this, leptin, a circulating adipose signal that regulates food intake and energy expenditure through central actions, blocks the glucocorticoid-mediated endocannabinoid release in the PVN. This represents a means by which the regulation of stress and feeding may interface in the PVN, thus providing a possible mechanism for the integration of multiple homeostatic functions.
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Affiliation(s)
- Jeffrey G Tasker
- Neurobiology Division, Department of Cell and Molecular Biology, Tulane University, 2000 Percival Stern Hall, New Orleans, LA 70118, USA.
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Yang C, Gagnon D, Vachon P, Tremblay A, Levy E, Massie B, Michaud JL. Adenoviral-mediated modulation of Sim1 expression in the paraventricular nucleus affects food intake. J Neurosci 2006; 26:7116-20. [PMID: 16807340 PMCID: PMC6673926 DOI: 10.1523/jneurosci.0672-06.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Haploinsufficency of Sim1, which codes for a basic helix-loop-helix-PAS (PER-ARNT-SIM) transcription factor, causes hyperphagia in mice and humans, without decrease in energy expenditure. Sim1 is expressed in several areas of the brain, including the developing and postnatal paraventricular nucleus (PVN), a region of the hypothalamus that controls food intake. We have previously found that the number of PVN cells is decreased in Sim1+/- mice, suggesting that their hyperphagia is caused by a developmental mechanism. However, the possibility that Sim1 functions in the postnatal PVN to control food intake cannot be ruled out. To explore this hypothesis, we used adenoviral vectors to modulate Sim1 expression in the postnatal PVN of wild-type mice. Unilateral stereotaxic injection into the PVN of an adenoviral vector producing a short hairpin RNA directed against Sim1 resulted in a significant increase in food intake, which peaked to 22% 6 d after the procedure, compared with the injection of a control virus. In contrast, injection of an adenovirus that expresses Sim1 induced a decrease in food intake that was maximal on the seventh day after the procedure, reaching 20%. The impact of bilateral injections of these vectors into the PVN was not greater than that of unilateral injections. Together, these results strongly suggest that Sim1 functions along a physiological pathway to control food intake.
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35
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Billings LB, Spero JA, Vollmer RR, Amico JA. Oxytocin null mice ingest enhanced amounts of sweet solutions during light and dark cycles and during repeated shaker stress. Behav Brain Res 2006; 171:134-41. [PMID: 16677726 DOI: 10.1016/j.bbr.2006.03.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/17/2006] [Accepted: 03/22/2006] [Indexed: 11/17/2022]
Abstract
Central oxytocin (OT) pathways appear to limit consumption of sweet solutions. Male and female C57BL/6 mice that lack the gene for oxytocin (OT KO mice) displayed an initial and sustained enhanced intake of sucrose solution over water compared to wild type (WT) mice when the solutions were presented as a two-bottle choice [Amico JA, Vollmer RR, Cai HM, Miedlar JA, Rinaman R. Enhanced initial and sustained intake of sucrose solution in mice with an oxytocin gene deletion. Am J Physiol: Regul Integr Comp Physiol 2005;289:R1798-806]. In this study we examined the ingestion of a non-nutritive sweetener, 0.2% saccharin in sucrose-experienced OT KO and WT mice given a two-bottle choice between saccharin solution and water available ad libitum for 4 days. Compared to WT mice, OT KO mice consumed significantly greater volumes of saccharin solution during the dark and light photoperiods on the first day and subsequent days of the study. The results were replicated when the experiment was repeated in the same animals. In another experiment, we determined that daily exposure to platform shaker stress did not alter the marked sucrose consumption in OT KO mice. OT KO mice drank significantly more sucrose than WT mice during periods of stress and non-stress. We conclude that the avid consumption of sweetened solutions by OT KO mice is not restricted to a single photoperiod, occurs independent of caloric content of the sweetened solution, and is not altered by exposure to the daily stress of platform shaker. The cumulative results from our studies of sucrose and saccharin ingestion in OT KO and WT male and female mice suggest a special role for sweet taste in the recruitment of OT neurons.
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Amico JA, Vollmer RR, Cai HM, Miedlar JA, Rinaman L. Enhanced initial and sustained intake of sucrose solution in mice with an oxytocin gene deletion. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1798-806. [PMID: 16150836 DOI: 10.1152/ajpregu.00558.2005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Laboratory mice drink little sucrose solution on initial exposure, but later develop a strong preference for sucrose over water that plateaus after a few days. Both the initial neophobia and later plateau of sucrose intake may involve central oxytocin (OT) signaling pathways. If so, then mice that lack the gene for OT [OT knockout (KO)] should exhibit enhanced initial and sustained sucrose intake compared with wild-type (WT) cohorts. To test this hypothesis, female OT KO and WT mice (11–13 mo old) were given a two-bottle choice between 10% sucrose and water available ad libitum for 4 days. On the first day, sucrose intake was 20-fold greater in OT KO mice compared with WT cohorts. The avid sucrose consumption by OT KO mice increased further on day 2 and was sustained at significantly higher levels than intake by WT mice. Enhanced initial and sustained sucrose intake also was observed in 5- to 7-mo-old male OT KO mice. The effect of genotype was observed over a range of sucrose concentrations and was maintained over at least 8 days of continual exposure. However, there was no effect of genotype on daily intake of sucrose-enriched powdered chow. These findings indicate that the genetic absence of OT in mice is associated with enhanced initial and sustained intake of sucrose solutions. Thus central OT pathways may normally participate in limiting initial intake of novel ingesta and may also participate in limiting intake of sweet, highly palatable familiar ingesta.
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Affiliation(s)
- Janet A Amico
- Department of Medicine, Univ. of Pittsburgh, Pittsburgh, PA 15261, USA.
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Caqueret A, Yang C, Duplan S, Boucher F, Michaud JL. Looking for trouble: a search for developmental defects of the hypothalamus. HORMONE RESEARCH 2005; 64:222-30. [PMID: 16227700 DOI: 10.1159/000088977] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The hypothalamus is a critical integrator of several homeostatic processes that are required for the survival of vertebrates. Disruption of the development of the hypothalamus thus has the potential of perturbing important physiological processes with lifelong consequences. We review current knowledge about how cell types are specified and circuits are formed within the developing hypothalamus. We emphasize the potential clinical impact of the perturbations of these pathways using the regulation of energy balance as a model. We predict that disruption of hypothalamic development is a common, previously unsuspected cause of disorders of homeostatic processes such as obesity and high blood pressure.
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