1
|
Berry MH, Leffler J, Allen CN, Sivyer B. Functional subtypes of rodent melanopsin ganglion cells switch roles between night and day illumination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.26.554902. [PMID: 38168436 PMCID: PMC10760181 DOI: 10.1101/2023.08.26.554902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs), contain the photopigment melanopsin, and influence both image and non-image forming behaviors. Despite being categorized into multiple types (M1-M6), physiological variability within these types suggests our current understanding of ipRGCs is incomplete. We used multi-electrode array (MEA) recordings and unbiased cluster analysis under synaptic blockade to identify 8 functional clusters of ipRGCs, each with distinct photosensitivity and response timing. We used Cre mice to drive the expression of channelrhodopsin in SON-ipRGCs, enabling the localization of distinct ipRGCs in the dorsal retina. Additionally, we conducted a retrospective unbiased cluster analysis of ipRGC photoresponses to light stimuli across scotopic, mesopic, and photopic intensities, aimed at activating both rod and cone inputs to ipRGCs. Our results revealed shared and distinct synaptic inputs to the identified functional clusters, demonstrating that ipRGCs encode visual information with high fidelity at low light intensities, but poorly at photopic light intensities, when melanopsin activation is highest. Collectively, our findings support a framework with at least 8 functional subtypes of ipRGCs, each encoding luminance with distinct spike outputs, highlighting the inherent functional diversity and complexity of ipRGCs and suggesting a reevaluation of their contributions to retinal function and visual perception under varying light conditions.
Collapse
Affiliation(s)
- Michael H. Berry
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
- Medical Scientist Training program, Oregon Health & Science University, Portland, OR, 97239
| | - Joseph Leffler
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
| | - Charles N. Allen
- Oregon Institute of Occupational Health Sciences, Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239
| | - Benjamin Sivyer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
| |
Collapse
|
2
|
Hassan S, El Baradey H, Madi M, Shebl M, Leng G, Lozic M, Ludwig M, Menzies J, MacGregor D. Measuring oxytocin release in response to gavage: Computational modelling and assay validation. J Neuroendocrinol 2023; 35:e13303. [PMID: 37316906 PMCID: PMC10909523 DOI: 10.1111/jne.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 04/18/2023] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
In the present experiments, we tested the conclusion from previous electrophysiological experiments that gavage of sweet food and systemically applied insulin both stimulate oxytocin secretion. To do so, we measured oxytocin secretion from urethane-anaesthetised male rats, and demonstrated a significant increase in secretion in response to gavage of sweetened condensed milk but not isocaloric cream, and a significant increase in response to intravenous injection of insulin. We compared the measurements made in response to sweetened condensed milk with the predictions from a computational model, which we used to predict plasma concentrations of oxytocin from the published electrophysiological responses of oxytocin cells. The prediction from the computational model was very closely aligned to the levels of oxytocin measured in rats in response to gavage.
Collapse
Affiliation(s)
- Shereen Hassan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Hala El Baradey
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mohamed Madi
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mohamed Shebl
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Maja Lozic
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - John Menzies
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Duncan MacGregor
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
3
|
Olszewski PK, Noble EE, Paiva L, Ueta Y, Blevins JE. Oxytocin as a potential pharmacological tool to combat obesity. J Neuroendocrinol 2022; 34:e13106. [PMID: 35192207 PMCID: PMC9372234 DOI: 10.1111/jne.13106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 11/30/2022]
Abstract
The neuropeptide oxytocin (OT) has emerged as an important anorexigen in the regulation of food intake and energy balance. It has been shown that the release of OT and activation of hypothalamic OT neurons coincide with food ingestion. Its effects on feeding have largely been attributed to limiting meal size through interactions in key regulatory brain regions governing the homeostatic control of food intake such as the hypothalamus and hindbrain in addition to key feeding reward areas such as the nucleus accumbens and ventral tegmental area. Furthermore, the magnitude of an anorexigenic response to OT and feeding-related activation of the brain OT circuit are modified by the composition and flavor of a diet, as well as by a social context in which a meal is consumed. OT is particularly effective in reducing consumption of carbohydrates and sweet tastants. Pharmacologic, genetic, and pair-feeding studies indicate that OT-elicited weight loss cannot be fully explained by reductions of food intake and that the overall impact of OT on energy balance is also partly a result of OT-elicited changes in lipolysis, energy expenditure, and glucose regulation. Peripheral administration of OT mimics many of its effects when it is given into the central nervous system, raising the questions of whether and to what extent circulating OT acts through peripheral OT receptors to regulate energy balance. Although OT has been found to elicit weight loss in female mice, recent studies have indicated that sex and estrous cycle may impact oxytocinergic modulation of food intake. Despite the overall promising basic research data, attempts to use OT in the clinical setting to combat obesity and overeating have generated somewhat mixed results. The focus of this mini-review is to briefly summarize the role of OT in feeding and metabolism, address gaps and inconsistencies in our knowledge, and discuss some of the limitations to the potential use of chronic OT that should help guide future research on OT as a tailor-made anti-obesity therapeutic.
Collapse
Affiliation(s)
- Pawel K Olszewski
- Faculty of Science and Engineering, University of Waikato, Waikato, New Zealand
- Department of Food Science and Nutrition, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St Paul, Minnesota, USA
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Emily E Noble
- Department of Nutritional Sciences, University of Georgia, Athens, Georgia, USA
| | - Luis Paiva
- Instituto de Ciencia Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan
| | - James E Blevins
- Department of Veterans Affairs Medical Center, VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Seattle, Washington, USA
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| |
Collapse
|
4
|
Oxytocin and Food Intake Control: Neural, Behavioral, and Signaling Mechanisms. Int J Mol Sci 2021; 22:ijms221910859. [PMID: 34639199 PMCID: PMC8509519 DOI: 10.3390/ijms221910859] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/29/2021] [Accepted: 10/03/2021] [Indexed: 11/16/2022] Open
Abstract
The neuropeptide oxytocin is produced in the paraventricular hypothalamic nucleus and the supraoptic nucleus of the hypothalamus. In addition to its extensively studied influence on social behavior and reproductive function, central oxytocin signaling potently reduces food intake in both humans and animal models and has potential therapeutic use for obesity treatment. In this review, we highlight rodent model research that illuminates various neural, behavioral, and signaling mechanisms through which oxytocin’s anorexigenic effects occur. The research supports a framework through which oxytocin reduces food intake via amplification of within-meal physiological satiation signals rather than by altering between-meal interoceptive hunger and satiety states. We also emphasize the distributed neural sites of action for oxytocin’s effects on food intake and review evidence supporting the notion that central oxytocin is communicated throughout the brain, at least in part, through humoral-like volume transmission. Finally, we highlight mechanisms through which oxytocin interacts with various energy balance-associated neuropeptide and endocrine systems (e.g., agouti-related peptide, melanin-concentrating hormone, leptin), as well as the behavioral mechanisms through which oxytocin inhibits food intake, including effects on nutrient-specific ingestion, meal size control, food reward-motivated responses, and competing motivations.
Collapse
|
5
|
Paiva L, Lozic M, Allchorne A, Grinevich V, Ludwig M. Identification of peripheral oxytocin-expressing cells using systemically applied cell-type specific adeno-associated viral vector. J Neuroendocrinol 2021; 33:e12970. [PMID: 33851744 DOI: 10.1111/jne.12970] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 12/11/2022]
Abstract
Oxytocin is primarily synthesised in the brain and is widely known for its role in lactation and parturition after being released into the blood from the posterior pituitary gland. Nevertheless, peripheral tissues have also been reported to express oxytocin. Using systemic injection of a recombinant adeno-associated virus vector, we investigated the expression of the green fluorescent protein Venus under the control of the oxytocin promoter in the gastrointestinal tract, pancreas and testes of adult rats. Here, we confirm that the vector infects oxytocin neurones of the enteric nervous system in ganglia of the myenteric and submucosal plexuses. Venus was detected in 25%-60% of the ganglia in the myenteric and submucosal plexuses identified by co-staining with the neuronal marker PGP9.5. Oxytocin expression was also detected in the islets of Langerhans in the pancreas and the Leydig cells of the testes. Our data illustrate that peripheral administration of the viral vector represents a powerful method for selectively labelling oxytocin-producing cells outside the brain.
Collapse
Affiliation(s)
- Luis Paiva
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Maja Lozic
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Andrew Allchorne
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University Heidelberg, Mannheim, Germany
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Department of Immunology, Centre for Neuroendocrinology, University of Pretoria, Pretoria, South Africa
| |
Collapse
|
6
|
Adjustment of Whey:Casein Ratio from 20:80 to 60:40 in Milk Formulation Affects Food Intake and Brainstem and Hypothalamic Neuronal Activation and Gene Expression in Laboratory Mice. Foods 2021; 10:foods10030658. [PMID: 33808819 PMCID: PMC8003661 DOI: 10.3390/foods10030658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 02/06/2023] Open
Abstract
Adjustment of protein content in milk formulations modifies protein and energy levels, ensures amino acid intake and affects satiety. The shift from the natural whey:casein ratio of ~20:80 in animal milk is oftentimes done to reflect the 60:40 ratio of human milk. Studies show that 20:80 versus 60:40 whey:casein milks differently affect glucose metabolism and hormone release; these data parallel animal model findings. It is unknown whether the adjustment from the 20:80 to 60:40 ratio affects appetite and brain processes related to food intake. In this set of studies, we focused on the impact of the 20:80 vs. 60:40 whey:casein content in milk on food intake and feeding-related brain processes in the adult organism. By utilising laboratory mice, we found that the 20:80 whey:casein milk formulation was consumed less avidly and was less preferred than the 60:40 formulation in short-term choice and no-choice feeding paradigms. The relative PCR analyses in the hypothalamus and brain stem revealed that the 20:80 whey:casein milk intake upregulated genes involved in early termination of feeding and in an interplay between reward and satiety, such as melanocortin 3 receptor (MC3R), oxytocin (OXT), proopiomelanocortin (POMC) and glucagon-like peptide-1 receptor (GLP1R). The 20:80 versus 60:40 whey:casein formulation intake differently affected brain neuronal activation (assessed through c-Fos, an immediate-early gene product) in the nucleus of the solitary tract, area postrema, ventromedial hypothalamic nucleus and supraoptic nucleus. We conclude that the shift from the 20:80 to 60:40 whey:casein ratio in milk affects short-term feeding and relevant brain processes.
Collapse
|
7
|
Paiva L, Leng G. Peripheral insulin administration enhances the electrical activity of oxytocin and vasopressin neurones in vivo. J Neuroendocrinol 2020; 32:e12841. [PMID: 32180284 DOI: 10.1111/jne.12841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 11/30/2022]
Abstract
Oxytocin neurones are involved in the regulation of energy balance through diverse central and peripheral actions and, in rats, they are potently activated by gavage of sweet substances. Here, we test the hypothesis that this activation is mediated by the central actions of insulin. We show that, in urethane-anaesthetised rats, oxytocin cells in the supraoptic nucleus show prolonged activation after i.v. injections of insulin, and that this response is greater in fasted rats than in non-fasted rats. Vasopressin cells are also activated, although less consistently. We also show that this activation of oxytocin cells is independent of changes in plasma glucose concentration, and is completely blocked by central (i.c.v.) administration of an insulin receptor antagonist. Finally, we replicate the previously published finding that oxytocin cells are activated by gavage of sweetened condensed milk, and show that this response too is completely blocked by central administration of an insulin receptor antagonist. We conclude that the response of oxytocin cells to gavage of sweetened condensed milk is mediated by the central actions of insulin.
Collapse
Affiliation(s)
- Luis Paiva
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Gareth Leng
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| |
Collapse
|
8
|
Plaisier F, Hume C, Menzies J. Neural connectivity between the hypothalamic supramammillary nucleus and appetite- and motivation-related regions of the rat brain. J Neuroendocrinol 2020; 32:e12829. [PMID: 31925973 PMCID: PMC7065010 DOI: 10.1111/jne.12829] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/06/2019] [Accepted: 01/08/2020] [Indexed: 12/20/2022]
Abstract
The supramammillary nucleus (SuM) has an emerging role in appetite control. We have shown that the rat SuM is activated during hunger or food anticipation, or by ghrelin administration. In the present study, we characterised the connectivity between the SuM and key appetite- and motivation-related nuclei in the rat. In adult wild-type rats, or rats expressing Cre recombinase under the control of the tyrosine hydroxylase (TH) promoter (TH-Cre rats), we used c-Fos immunohistochemistry to visualise and correlate the activation of medial SuM (SuMM) with activation in the lateral hypothalamic area (LH), the dorsomedial hypothalamus (DMH) or the ventral tegmental area (VTA) after voluntary consumption of a high-sugar, high-fat food. To determine neuroanatomical connectivity, we used retrograde and anterograde tracing methods to specifically investigate the neuronal inputs and outputs of the SuMM. After consumption of the food there were positive correlations between c-Fos expression in the SuMM and the LH, DMH and VTA (P = 0.0001, 0.01 and 0.004). Using Fluoro-Ruby as a retrograde tracer, we demonstrate the existence of inputs from the LH, DMH, VTA and ventromedial hypothalamus (VMH) to the SuMM. The SuMM showed reciprocal inputs to the LH and DMH, and we identified a TH-positive output from SuMM to DMH. We co-labelled retrogradely-labelled sections for TH in the VMH, or for TH, orexin and melanin-concentrating hormone in the LH and DMH. However, we did not observe any colocalisation of immunoreactivity with any retrogradely-labelled cells. Viral mapping in TH-Cre rats confirms the existence of a reciprocal SuMM-DMH connection and shows that TH-positive cells project from the SuMM and VTA to the lateral septal area and cingulate cortex, respectively. These data provide evidence for the connectivity of the SuMM to brain regions involved in appetite control, and form the foundation for functional and behavioural studies aiming to further characterise the brain circuitry controlling eating behaviours.
Collapse
Affiliation(s)
- Fabrice Plaisier
- Centre for Discovery Brain SciencesEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Catherine Hume
- Centre for Discovery Brain SciencesEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - John Menzies
- Centre for Discovery Brain SciencesEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
- ZJU‐UoE InstituteZhejiang University School of Medicine, Zhejiang University International CampusHainingZhejiangChina
| |
Collapse
|
9
|
Hume C, Leng G. Oxytocin neurons: integrators of hypothalamic and brainstem circuits in the regulation of macronutrient-specific satiety. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Liu CM, Davis EA, Suarez AN, Wood RI, Noble EE, Kanoski SE. Sex Differences and Estrous Influences on Oxytocin Control of Food Intake. Neuroscience 2019; 447:63-73. [PMID: 31738883 DOI: 10.1016/j.neuroscience.2019.10.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 10/25/2022]
Abstract
Central oxytocin potently reduces food intake and is being pursued as a clinical treatment for obesity. While sexually dimorphic effects have been described for the effects of oxytocin on several behavioral outcomes, the role of sex in central oxytocin modulation of feeding behavior is poorly understood. Here we investigated the effects of sex, estrous cycle stage, and female sex hormones (estrogen, progesterone) on central oxytocin-mediated reduction of food intake in rats. Results show that while intracerebroventricular (ICV) oxytocin potently reduces chow intake in both male and female rats, these effects were more pronounced in males than in females. We next examined whether estrous cycle stage affects oxytocin's food intake-reducing effects in females. Results show that ICV oxytocin administration significantly reduces food intake during all estrous cycle stages except proestrous, suggesting that female sex hormones may modulate the feeding effects of oxytocin. Indeed, additional results reveal that estrogen, but not progesterone replacement, in ovariectomized rats abolishes oxytocin-mediated reductions in chow intake. Lastly, oxytocin receptor mRNA (Oxtr) quantification (via quantitative PCR) and anatomical localization (via fluorescent in situ hybridization) in previously established sites of action for oxytocin control of food intake revealed comparable Oxtr expression between male and female rats, suggesting that observed sex and estrous differences may be based on variations in ligand availability and/or binding. Overall, these data show that estrogen reduces the effectiveness of central oxytocin to inhibit food intake, suggesting that sex hormones and estrous cycle should be considered in clinical investigations of oxytocin for obesity treatment.
Collapse
Affiliation(s)
- Clarissa M Liu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, United States; Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, United States
| | - Elizabeth A Davis
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, United States
| | - Andrea N Suarez
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, United States
| | - Ruth I Wood
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, United States; Department of Integrative Anatomical Sciences, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States
| | - Emily E Noble
- Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, United States; Department of Foods and Nutrition, University of Georgia, Athens, GA, United States.
| | - Scott E Kanoski
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, United States; Department of Biological Sciences, Human and Evolutionary Biology Section, University of Southern California, Los Angeles, CA, United States.
| |
Collapse
|
11
|
Le May MV, Hume C, Sabatier N, Schéle E, Bake T, Bergström U, Menzies J, Dickson SL. Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration. J Neuroendocrinol 2019; 31:e12676. [PMID: 30580497 DOI: 10.1111/jne.12676] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/16/2018] [Accepted: 12/10/2018] [Indexed: 01/24/2023]
Abstract
The circulating orexigenic hormone ghrelin targets many brain areas involved in feeding control and signals via a dedicated receptor, the growth hormone secretagogue receptor 1A. One unexplored target area for ghrelin is the supramammillary nucleus (SuM), a hypothalamic area involved in motivation and reinforcement and also recently linked to metabolic control. Given that ghrelin binds to the SuM, we explored whether SuM cells respond to ghrelin and/or are activated when endogenous ghrelin levels are elevated. We found that peripheral ghrelin injection activates SuM cells in rats, reflected by an increase in the number of cells expressing c-Fos protein in this area, as welll as by the predominantly excitatory response of single SuM cells recorded in in vivo electrophysiological studies. Further c-Fos mapping studies reveal that this area is also activated in rats in situations when circulating ghrelin levels are known to be elevated: in food-restricted rats anticipating the consumption of food and in fed rats anticipating the consumption of an energy-dense food. We also show that intra-SuM injection of ghrelin induces a feeding response in rats suggesting that, if peripheral ghrelin is able to access the SuM, it may have direct effects on this brain region. Collectively, our data demonstrate that the SuM is activated when peripheral ghrelin levels are high, further supporting the emerging role for this brain area in metabolic and feeding control.
Collapse
Affiliation(s)
- Marie V Le May
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Catherine Hume
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Nancy Sabatier
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Erik Schéle
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Tina Bake
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Ulrika Bergström
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - John Menzies
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Suzanne L Dickson
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
12
|
Nudge, nudge, eat, drink…. FOOD SCIENCE AND TECHNOLOGY 2019. [DOI: 10.1002/fsat.3301_10.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
13
|
Leng G, Russell JA. The osmoresponsiveness of oxytocin and vasopressin neurones: Mechanisms, allostasis and evolution. J Neuroendocrinol 2019; 31:e12662. [PMID: 30451331 DOI: 10.1111/jne.12662] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/29/2018] [Accepted: 11/15/2018] [Indexed: 12/27/2022]
Abstract
In the rat supraoptic nucleus, every oxytocin cell projects to the posterior pituitary, and is involved both in reflex milk ejection during lactation and in regulating uterine contractions during parturition. All are also osmosensitive, regulating natriuresis. All are also regulated by signals that control appetite, including the neural and hormonal signals that arise from the gut after food intake and from the sites of energy storage. All are also involved in sexual behaviour, anxiety-related behaviours and social behaviours. The challenge is to understand how a single population of neurones can coherently regulate such a diverse set of functions and adapt to changing physiological states. Their multiple functions arise from complex intrinsic properties that confer sensitivity to a wide range of internal and environmental signals. Many of these properties have a distant evolutionary origin in multifunctional, multisensory neurones of Urbilateria, the hypothesised common ancestor of vertebrates, insects and worms. Their properties allow different patterns of oxytocin release into the circulation from their axon terminals in the posterior pituitary into other brain areas from axonal projections, as well as independent release from their dendrites.
Collapse
Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - John A Russell
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| |
Collapse
|
14
|
Onaka T, Takayanagi Y. Role of oxytocin in the control of stress and food intake. J Neuroendocrinol 2019; 31:e12700. [PMID: 30786104 PMCID: PMC7217012 DOI: 10.1111/jne.12700] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/20/2022]
Abstract
Oxytocin neurones in the hypothalamus are activated by stressful stimuli and food intake. The oxytocin receptor is located in various brain regions, including the sensory information-processing cerebral cortex; the cognitive information-processing prefrontal cortex; reward-related regions such as the ventral tegmental areas, nucleus accumbens and raphe nucleus; stress-related areas such as the amygdala, hippocampus, ventrolateral part of the ventromedial hypothalamus and ventrolateral periaqueductal gray; homeostasis-controlling hypothalamus; and the dorsal motor complex controlling intestinal functions. Oxytocin affects behavioural and neuroendocrine stress responses and terminates food intake by acting on the metabolic or nutritional homeostasis system, modulating emotional processing, reducing reward values of food intake, and facilitating sensory and cognitive processing via multiple brain regions. Oxytocin also plays a role in interactive actions between stress and food intake and contributes to adaptive active coping behaviours.
Collapse
Affiliation(s)
- Tatsushi Onaka
- Division of Brain and NeurophysiologyDepartment of PhysiologyJichi Medical UniversityShimotsuke‐shiJapan
| | - Yuki Takayanagi
- Division of Brain and NeurophysiologyDepartment of PhysiologyJichi Medical UniversityShimotsuke‐shiJapan
| |
Collapse
|
15
|
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.
Collapse
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.
| |
Collapse
|
16
|
Yuan XS, Wei HH, Xu W, Wang L, Qu WM, Li RX, Huang ZL. Whole-Brain Monosynaptic Afferent Projections to the Cholecystokinin Neurons of the Suprachiasmatic Nucleus. Front Neurosci 2018; 12:807. [PMID: 30455627 PMCID: PMC6230653 DOI: 10.3389/fnins.2018.00807] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/16/2018] [Indexed: 11/24/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) is the principal pacemaker driving the circadian rhythms of physiological behaviors. The SCN consists of distinct neurons expressing neuropeptides, including arginine vasopressin (AVP), vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP), cholecystokinin (CCK), and so on. AVP, VIP, and GRP neurons receive light stimulation from the retina to synchronize endogenous circadian clocks with the solar day, whereas CCK neurons are not directly innervated by retinal ganglion cells and may be involved in the non-photic regulation of the circadian clock. To better understand the function of CCK neurons in non-photic circadian rhythm, it is vital to clarify the direct afferent inputs to CCK neurons in the SCN. Here, we utilized a recently developed rabies virus- and Cre/loxP-based, cell type-specific, retrograde tracing system to map and quantitatively analyze the whole-brain monosynaptic inputs to SCN CCK neurons. We found that SCN CCK neurons received direct inputs from 29 brain nuclei. Among these nuclei, paraventricular nucleus of the hypothalamus (PVH), paraventricular nucleus of the thalamus (PVT), supraoptic nucleus (SON), ventromedial nucleus of the hypothalamus, and seven other nuclei sent numerous inputs to CCK neurons. Moderate inputs originated from the zona incerta, periventricular hypothalamic nucleus, and five other nuclei. A few inputs to CCK neurons originated from the orbital frontal cortex, prelimbic cortex, cingulate cortex, claustrum, and seven other nuclei. In addition, SCN CCK neurons were preferentially innervated by AVP neurons of the ipsilateral PVH and SON rather than their contralateral counterpart, whereas the contralateral PVT sent more projections to CCK neurons than to its ipsilateral counterpart. Taken together, these results expand our knowledge of the specific innervation to mouse SCN CCK neurons and provide an important indication for further investigations on the function of CCK neurons.
Collapse
Affiliation(s)
- Xiang-Shan Yuan
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Hao-Hua Wei
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Wei Xu
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Lu Wang
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Rui-Xi Li
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Zhi-Li Huang
- Department of Pharmacology, Department of Anatomy, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| |
Collapse
|
17
|
Matsui S, Sasaki T, Kohno D, Yaku K, Inutsuka A, Yokota-Hashimoto H, Kikuchi O, Suga T, Kobayashi M, Yamanaka A, Harada A, Nakagawa T, Onaka T, Kitamura T. Neuronal SIRT1 regulates macronutrient-based diet selection through FGF21 and oxytocin signalling in mice. Nat Commun 2018; 9:4604. [PMID: 30389922 PMCID: PMC6214990 DOI: 10.1038/s41467-018-07033-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 10/12/2018] [Indexed: 12/02/2022] Open
Abstract
Diet affects health through ingested calories and macronutrients, and macronutrient balance affects health span. The mechanisms regulating macronutrient-based diet choices are poorly understood. Previous studies had shown that NAD-dependent deacetylase sirtuin-1 (SIRT1) in part influences the health-promoting effects of caloric restriction by boosting fat use in peripheral tissues. Here, we show that neuronal SIRT1 shifts diet choice from sucrose to fat in mice, matching the peripheral metabolic shift. SIRT1-mediated suppression of simple sugar preference requires oxytocin signalling, and SIRT1 in oxytocin neurons drives this effect. The hepatokine FGF21 acts as an endocrine signal to oxytocin neurons, promoting neuronal activation and Oxt transcription and suppressing the simple sugar preference. SIRT1 promotes FGF21 signalling in oxytocin neurons and stimulates Oxt transcription through NRF2. Thus, neuronal SIRT1 contributes to the homeostatic regulation of macronutrient-based diet selection in mice.
Collapse
Affiliation(s)
- Sho Matsui
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Tsutomu Sasaki
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan.
| | - Daisuke Kohno
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
- Advanced Scientific Research Leaders Development Unit, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Keisuke Yaku
- Frontier Research Core for Life Science, University of Toyama, 2630 Sugitani, Toyama, Toyama, 930-0194, Japan
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama, 930-0194, Japan
| | - Ayumu Inutsuka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furocho, Nagoya, 464-8601, Japan
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Hiromi Yokota-Hashimoto
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Osamu Kikuchi
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Takayoshi Suga
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Masaki Kobayashi
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furocho, Nagoya, 464-8601, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takashi Nakagawa
- Frontier Research Core for Life Science, University of Toyama, 2630 Sugitani, Toyama, Toyama, 930-0194, Japan
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama, 930-0194, Japan
| | - Tatsushi Onaka
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan
| | - Tadahiro Kitamura
- Laboratory of Metabolic Signal, Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan.
| |
Collapse
|
18
|
Najam SS, Zglinicki B, Vinnikov IA, Konopka W. MicroRNAs in the hypothalamic control of energy homeostasis. Cell Tissue Res 2018; 375:173-177. [DOI: 10.1007/s00441-018-2876-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/19/2018] [Indexed: 11/28/2022]
|
19
|
Maejima Y, Yokota S, Nishimori K, Shimomura K. The Anorexigenic Neural Pathways of Oxytocin and Their Clinical Implication. Neuroendocrinology 2018; 107:91-104. [PMID: 29660735 DOI: 10.1159/000489263] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 04/15/2018] [Indexed: 12/21/2022]
Abstract
Oxytocin was discovered in 1906 as a peptide that promotes delivery and milk ejection; however, its additional physiological functions were determined 100 years later. Many recent articles have reported newly discovered effects of oxytocin on social communication, bonding, reward-related behavior, adipose tissue, and muscle and food intake regulation. Because oxytocin neurons project to various regions in the brain that contribute to both feeding reward (hedonic feeding) and the regulation of energy balance (homeostatic feeding), the mechanisms of oxytocin on food intake regulation are complicated and largely unknown. Oxytocin neurons in the paraventricular nucleus (PVN) receive neural projections from the arcuate nucleus (ARC), which is an important center for feeding regulation. On the other hand, these neurons in the PVN and supraoptic nucleus project to the ARC. PVN oxytocin neurons also project to the brain stem and the reward-related limbic system. In addition to this, oxytocin induces lipolysis and decreases fat mass. However, these effects in feeding and adipose tissue are known to be dependent on body weight (BW). Oxytocin treatment is more effective in food intake regulation and fat mass decline for individuals with leptin resistance and higher BW, but is known to be less effective in individuals with normal BW. In this review, we present in detail the recent findings on the physiological role of oxytocin in feeding regulation and the anorexigenic neural pathway of oxytocin neurons, as well as the advantage of oxytocin usage for anti-obesity treatment.
Collapse
Affiliation(s)
- Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Shoko Yokota
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Katsuhiko Nishimori
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| |
Collapse
|