1
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Hirako S, Wada N, Iizuka Y, Hirabayashi T, Kageyama H, Kim H, Kaibara N, Yanagisawa N, Takenoya F, Shioda S. Effect of Intracerebroventricular Administration of Galanin-Like Peptide on Hepatokines in C57BL/6 J Mice. J Mol Neurosci 2024; 74:25. [PMID: 38386221 DOI: 10.1007/s12031-024-02200-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/06/2024] [Indexed: 02/23/2024]
Abstract
Galanin-like peptide (GALP) is a neuropeptide that was first isolated and identified from the porcine hypothalamus. Studies have described an anti-obesity effect of GALP. We previously found that intracerebroventricular administration of GALP in mice resulted in an increase in respiratory exchange rate 12 to 16 h later. GALP may also affect glucose metabolism, but the detailed mechanism has not been elucidated. In this study, we investigated the effects of GALP on glucose and lipid metabolism in the liver. Nine-week-old male C57BL / 6 J mice were administered a single intracerebroventricular dose of saline or GALP and dissected 16 h later. There were no significant between-group differences in body weight and blood glucose levels. With regard to gene and protein expression, G6Pase associated with hepatic gluconeogenesis was significantly reduced in the GALP group. In addition, the hepatokines selenoprotein P and fetuin-A, which induce insulin resistance in the liver, were significantly decreased in the GALP group. These results suggest that intracerebroventricular administration of GALP decreases the expression of key hepatokines, thereby enhancing glucose metabolism.
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Affiliation(s)
- Satoshi Hirako
- Department of Health and Nutrition, University of Human Arts and Sciences, 1288 Magome, Iwatsuki-ku, Saitama-shi, Saitama, 339-8539, Japan
| | - Nobuhiro Wada
- Department of Anatomy, Sapporo Medical University School of Medicine, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan
| | - Yuzuru Iizuka
- Department of Microbiology and Immunology, Tokyo Women's Medical University School of Medicine, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Takahiro Hirabayashi
- Clinical Medicine Research Laboratory, Shonan University of Medical Sciences, 16-48 Kamishinano, Totsuka-ku, Yokohama-shi, Kanagawa, 244-0806, Japan
| | - Haruaki Kageyama
- Department of Nutrition and Dietetics, Faculty of Family and Consumer Sciences, Kamakura Women's University, 6-1-3 Ofuna, Kamakura-shi, Kanagawa, 247-8512, Japan
| | - Hyounju Kim
- Department of Nutrition and Health Sciences, Faculty of Food and Nutritional Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma, 374-0193, Japan
| | - Naoko Kaibara
- Department of Health and Nutrition, University of Human Arts and Sciences, 1288 Magome, Iwatsuki-ku, Saitama-shi, Saitama, 339-8539, Japan
| | - Naoko Yanagisawa
- Department of Microbiology and Immunology, Tokyo Women's Medical University School of Medicine, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Fumiko Takenoya
- Department of Sport Sciences, School of Pharmacy, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
| | - Seiji Shioda
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Shonan University of Medical Sciences, 16-10, Kamishinano, Totsuka-ku, Yokohama-shi, Kanagawa, 244-0806, Japan
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2
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Takenoya F, Shibato J, Yamashita M, Kimura A, Hirako S, Chiba Y, Nonaka N, Shioda S, Rakwal R. Transcriptomic (DNA Microarray) and Metabolome (LC-TOF-MS) Analyses of the Liver in High-Fat Diet Mice after Intranasal Administration of GALP (Galanin-like Peptide). Int J Mol Sci 2023; 24:15825. [PMID: 37958806 PMCID: PMC10648535 DOI: 10.3390/ijms242115825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/20/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023] Open
Abstract
The aim of this research was to test the efficacy and potential clinical application of intranasal administration of galanin-like peptide (GALP) as an anti-obesity treatment under the hypothesis that GALP prevents obesity in mice fed a high-fat diet (HFD). Focusing on the mechanism of regulation of lipid metabolism in peripheral tissues via the autonomic nervous system, we confirmed that, compared with a control (saline), intranasally administered GALP prevented further body weight gain in diet-induced obesity (DIO) mice with continued access to an HFD. Using an omics-based approach, we identified several genes and metabolites in the liver tissue of DIO mice that were altered by the administration of intranasal GALP. We used whole-genome DNA microarray and metabolomics analyses to determine the anti-obesity effects of intranasal GALP in DIO mice fed an HFD. Transcriptomic profiling revealed the upregulation of flavin-containing dimethylaniline monooxygenase 3 (Fmo3), metallothionein 1 and 2 (Mt1 and Mt2, respectively), and the Aldh1a3, Defa3, and Defa20 genes. Analysis using the DAVID tool showed that intranasal GALP enhanced gene expression related to fatty acid elongation and unsaturated fatty acid synthesis and downregulated gene expression related to lipid and cholesterol synthesis, fat absorption, bile uptake, and excretion. Metabolite analysis revealed increased levels of coenzyme Q10 and oleoylethanolamide in the liver tissue, increased levels of deoxycholic acid (DCA) and taurocholic acid (TCA) in the bile acids, increased levels of taurochenodeoxycholic acid (TCDCA), and decreased levels of ursodeoxycholic acid (UDCA). In conclusion, intranasal GALP administration alleviated weight gain in obese mice fed an HFD via mechanisms involving antioxidant, anti-inflammatory, and fatty acid metabolism effects and genetic alterations. The gene expression data are publicly available at NCBI GSE243376.
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Affiliation(s)
- Fumiko Takenoya
- Department of Sport Sciences, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan; (F.T.); (M.Y.); (A.K.)
| | - Junko Shibato
- Department of Functional Morphology, Shonan University of Medical Sciences, Kanagawa 244-0806, Japan; (J.S.); (S.S.)
| | - Michio Yamashita
- Department of Sport Sciences, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan; (F.T.); (M.Y.); (A.K.)
| | - Ai Kimura
- Department of Sport Sciences, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan; (F.T.); (M.Y.); (A.K.)
| | - Satoshi Hirako
- Department of Health and Nutrition, University of Human Arts and Sciences, Saitama 339-8539, Japan;
| | - Yoshihiko Chiba
- Laboratory of Molecular Biology and Physiology, School of Pharmacy, Hoshi University, Tokyo 142-8501, Japan;
| | - Naoko Nonaka
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, Tokyo 142-8555, Japan;
| | - Seiji Shioda
- Department of Functional Morphology, Shonan University of Medical Sciences, Kanagawa 244-0806, Japan; (J.S.); (S.S.)
| | - Randeep Rakwal
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba 305-8574, Japan
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3
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Kuipers A, Balaskó M, Pétervári E, Koller A, Brunner SM, Moll GN, Kofler B. Intranasal Delivery of a Methyllanthionine-Stabilized Galanin Receptor-2-Selective Agonist Reduces Acute Food Intake. Neurotherapeutics 2021; 18:2737-2752. [PMID: 34859381 PMCID: PMC8804135 DOI: 10.1007/s13311-021-01155-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2021] [Indexed: 11/27/2022] Open
Abstract
The regulatory (neuro)peptide galanin is widely distributed in the central and peripheral nervous systems, where it mediates its effects via three G protein-coupled receptors (GAL1-3R). Galanin has a vast diversity of biological functions, including modulation of feeding behavior. However, the clinical application of natural galanin is not practicable due to its rapid in vivo breakdown by peptidases and lack of receptor subtype specificity. Much effort has been put into the development of receptor-selective agonists and antagonists, and while receptor selectivity has been attained to some degree, most ligands show overlapping affinity. Therefore, we aimed to develop a novel ligand with specificity to a single galanin receptor subtype and increased stability. To achieve this, a lanthionine amino acid was enzymatically introduced into a galanin-related peptide. The residue's subsequent cyclization created a conformational constraint which increased the peptide's receptor specificity and proteolytic resistance. Further exchange of certain other amino acids resulted in a novel methyllanthionine-stabilized galanin receptor agonist, a G1pE-T3N-S6A-G12A-methyllanthionine[13-16]-galanin-(1-17) variant, termed M89b. M89b has exclusive specificity for GAL2R and a prolonged half-life in serum. Intranasal application of M89b to unfasted rats significantly reduced acute 24 h food intake inducing a drop in body weight. Combined administration of M89b and M871, a selective GAL2R antagonist, abolished the anorexigenic effect of M89b, indicating that the effect of M89b on food intake is indeed mediated by GAL2R. This is the first demonstration of in vivo activity of an intranasally administered lanthipeptide. Consequently, M89b is a promising candidate for clinical application as a galanin-related peptide-based therapeutic.
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Affiliation(s)
- Anneke Kuipers
- Lanthio Health B.V., Rozenburglaan 13B, 9727 DL, Groningen, Netherlands
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti út, H-7624, Pécs, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti út, H-7624, Pécs, Hungary
| | - Andreas Koller
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria
- Research Program for Experimental Ophthalmology, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Susanne M Brunner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria
- Research Program for Experimental Ophthalmology, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Gert N Moll
- Lanthio Health B.V., Rozenburglaan 13B, 9727 DL, Groningen, Netherlands
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, Netherlands
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
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Oliveira Volpe CM, Vaz T, Rocha-Silva F, Villar-Delfino PH, Nogueira-Machado JA. Is Galanin a Promising Therapeutic Resource for Neural and Nonneural Diseases? Curr Drug Targets 2021; 21:922-929. [PMID: 32096740 DOI: 10.2174/1389450121666200225112055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Galanin (GAL) constitutes a family of neuropeptides composed of four peptides: (i) galanin (GAL), (ii) galanin-message associated peptide (GAMP), (iii) galanin-like peptide (GALP), and (iv) alarin. GAL contains 29/30 amino acids, and its biological action occurs through the interactions with its various receptors (GALR1, GALR2, and GALR3). The neuropeptide GAL regulates several physiological and pathophysiological functions in the central nervous system, the peripheral nervous system, and the peripheral organs. GAL is secreted mainly by oligodendrocytes, astrocytes, and the gastrointestinal tract, and its effect depends on the interaction with its different receptors. These receptors are expressed mainly in the central, peripheral nervous systems and the intestines. OBJECTIVE The present review evaluates the role of GAL family in inflammatory diseases. An overview is given of the signaling and pharmacological effects due to the interaction between GAL and GALR in different cell types. The potential use of GAL as a therapeutic resource is critically discussed. CONCLUSION GAL is suggested to have an anti-inflammatory function in some situations and a proinflammatory function in others. The literature on GAL is controversial and currently not conclusive. This could be due to the complexity of the metabolic network signaling induced by the interactions between GAL and GALR. In the next future, GAL might be a promising therapeutic resource for several diseases, but its practical use for disease control is presently not advisable.
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Affiliation(s)
- Caroline Maria Oliveira Volpe
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Tatiana Vaz
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Fabiana Rocha-Silva
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - Pedro Henrique Villar-Delfino
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
| | - José Augusto Nogueira-Machado
- Nucleo de Pos-Graduacao e Pesquisa, Hospital Santa Casa de Belo Horizonte, Rua Domingos Vieira 590, Santa Efigenia, 30150-240, Belo Horizonte, MG, Brazil
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Dudás B, Merchenthaler I. Morphology and distribution of hypothalamic peptidergic systems. HANDBOOK OF CLINICAL NEUROLOGY 2021; 179:67-85. [PMID: 34225984 DOI: 10.1016/b978-0-12-819975-6.00002-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neuropeptides participate in the regulation of numerous hypothalamic functions that are aimed for sustaining the homeostasis of the organism. These neuropeptides can act in two different levels. They can influence the release of hormones from the adenohypophysis via the portal circulation; in addition, they can act as neurotransmitters/neuromodulators modulating the functioning of numerous hypothalamic neurotransmitter systems. Indeed, most of these peptidergic systems form a complex network in the infundibular and periventricular nuclei of the human hypothalamus, communicating with each other by synaptic connections that may control fundamental physiologic functions. In the present chapter, we provide an overview of the distribution of neuropeptides in the human hypothalamus using immunohistochemistry and high-resolution, three-dimensional mapping.
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Affiliation(s)
- Bertalan Dudás
- Neuroendocrine Organization Laboratory, Lake Erie College of Osteopathic Medicine, Erie, PA, United States; Department of Anatomy, Histology and Embryology, University of Szeged, Szeged, Hungary.
| | - István Merchenthaler
- Department of Epidemiology and Public Health and of Anatomy and Neurobiology, University of Maryland Baltimore, Baltimore, MD, United States
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6
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Galanin is a potent modulator of cytokine and chemokine expression in human macrophages. Sci Rep 2019; 9:7237. [PMID: 31076613 PMCID: PMC6510899 DOI: 10.1038/s41598-019-43704-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 04/26/2019] [Indexed: 12/14/2022] Open
Abstract
The regulatory peptide galanin is broadly distributed in the central- and peripheral nervous systems as well as in non-neuronal tissues, where it exerts its diverse physiological functions via three G-protein-coupled receptors (GAL1-3-R). Regulatory peptides are important mediators of the cross-communication between the nervous- and immune systems and have emerged as a focus of new therapeutics for a variety of inflammatory diseases. Studies on inflammatory animal models and immune cells revealed both pro- and anti-inflammatory functions of galanin. Here, we probed specific immune-related functions of the galanin system and found galanin and GAL1-R and GAL2-R mRNA to be expressed in a range of human immune cells. In particular, macrophages displayed differentiation- and polarization-dependent expression of galanin and its receptors. Exposure to exogenous galanin affected the cytokine/chemokine expression profile of macrophages differently, depending on their differentiation and polarization, and mainly modulated the expression of chemokines (CCL2, CCL3, CCL5 and CXCL8) and anti-inflammatory cytokines (TGF-β, IL-10 and IL-1Ra), especially in type-1 macrophages. Cytokine/chemokine expression levels in interferon-gamma- and lipopolysaccharide-polarized macrophages were upregulated whereas in unpolarized macrophages they were downregulated upon galanin treatment for 20 hours. This study illuminates the regulation of important cytokines/chemokines in macrophages by galanin, depending on specific cell activation.
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7
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Kageyama H, Shiba K, Hirako S, Wada N, Yamanaka S, Nogi Y, Takenoya F, Nonaka N, Hirano T, Inoue S, Shioda S. Anti-obesity effect of intranasal administration of galanin-like peptide (GALP) in obese mice. Sci Rep 2016; 6:28200. [PMID: 27323911 PMCID: PMC4914964 DOI: 10.1038/srep28200] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 06/01/2016] [Indexed: 11/09/2022] Open
Abstract
Galanin-like peptide (GALP) has an anti-obesity effect in rats and mice. It has been reported that the uptake of GALP by the brain is higher after intranasal administration than with intravenous injection. This study therefore aimed to clarify the effect of intranasal administration of GALP on the feeding behavior of lean and obese mice. Autoradiography revealed the presence of (125)I-GALP in the olfactory bulb and the brain microcirculation. The body weights of ob/ob mice gradually increased during vehicle treatment, but remained unchanged in response to repeated intranasal administration of GALP, with both ob/ob and diet-induced obese mice displaying significantly decreased food intake, water intake and locomotor activity when treated with GALP. These results suggest that intranasal administration is an effective route whereby GALP can exert its effect as an anti-obesity drug.
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Affiliation(s)
- Haruaki Kageyama
- Division of Nutrition, Faculty of Health Care, Kiryu University, Gunma 379-2392, Japan
| | - Kanako Shiba
- Department of Anatomy, Showa University School of Medicine, Tokyo, 142-8555, Japan
| | - Satoshi Hirako
- Department of Health and Nutrition, University of Human Arts and Sciences, Saitama 339-8539, Japan
| | - Nobuhiro Wada
- Department of Anatomy, Showa University School of Medicine, Tokyo, 142-8555, Japan.,Department of Internal Medicine, Graduate school of Medicine, University of Tokyo, Tokyo 113-8655, Japan
| | - Satoru Yamanaka
- Department of Anatomy, Showa University School of Medicine, Tokyo, 142-8555, Japan
| | - Yukinori Nogi
- Department of Medicine, Division of Diabetes, Metabolism, and Endocrinology, Showa University School of Medicine, Tokyo 142-8555, Japan
| | - Fumiko Takenoya
- Department of Exercise and Sports Physiology, Hoshi University School of Pharmacy and Pharmaceutical Science, Tokyo 142-8501, Japan
| | - Naoko Nonaka
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, Tokyo 142-8555, Japan
| | - Tsutomu Hirano
- Department of Medicine, Division of Diabetes, Metabolism, and Endocrinology, Showa University School of Medicine, Tokyo 142-8555, Japan
| | - Shuji Inoue
- Division of Nutrition, Faculty of Health Care, Kiryu University, Gunma 379-2392, Japan
| | - Seiji Shioda
- Hoshi University School of Pharmacy and Pharmaceutical Sciences, Global Research Center for Innovative Life Science, Peptide Drug Innovation, Tokyo 142-8501, Japan
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Petschner P, Juhasz G, Tamasi V, Adori C, Tothfalusi L, Hökfelt T, Bagdy G. Chronic venlafaxine treatment fails to alter the levels of galanin system transcripts in normal rats. Neuropeptides 2016; 57:65-70. [PMID: 26891823 DOI: 10.1016/j.npep.2016.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/22/2016] [Accepted: 01/31/2016] [Indexed: 11/16/2022]
Abstract
It is widely accepted that efficacy and speed of current antidepressants' therapeutic effect are far from optimal. Thus, there is a need for the development of antidepressants with new mechanisms of action. The neuropeptide galanin and its receptors (GalR1, GalR2 and GalR3) are among the promising targets. However, it is not clear whether or not the galanin system is involved in the antidepressant effect exerted by the currently much used inhibitors of the reuptake of serotonin and/or noradrenaline. To answer this question we administered the selective serotonin and noradrenaline reuptake inhibitor (SNRI) venlafaxine (40mg/kg/day via osmotic minipumps) to normal rats and examined the levels of the transcripts for galanin and GalR1-3 after a 3-week venlafaxine treatment in the dorsal raphe, hippocampus and frontal cortex. These areas are known to be involved in the effects of antidepressants and in depression itself. Venlafaxine failed to alter the expression of any of the galanin system genes in these areas. Our results show that one of the most efficient, currently used SNRIs does not alter transcript levels of galanin or its three receptors in normal rats. These findings suggest that the pro- and antidepressive-like effects of galanin reported in animal experiments may employ a novel mechanism(s).
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Affiliation(s)
- Peter Petschner
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Gabriella Juhasz
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE-NAP B Genetic Brain Imaging Migraine Research Group, Hungarian Academy of Sciences, Semmelweis University, Hungary
| | - Viola Tamasi
- Department of Genetics-, Cell and Immunobiology, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Csaba Adori
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Laszlo Tothfalusi
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Tomas Hökfelt
- Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary.
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9
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Hirako S, Wada N, Kageyama H, Takenoya F, Izumida Y, Kim H, Iizuka Y, Matsumoto A, Okabe M, Kimura A, Suzuki M, Yamanaka S, Shioda S. Autonomic nervous system-mediated effects of galanin-like peptide on lipid metabolism in liver and adipose tissue. Sci Rep 2016; 6:21481. [PMID: 26892462 PMCID: PMC4759810 DOI: 10.1038/srep21481] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/18/2016] [Indexed: 01/21/2023] Open
Abstract
Galanin-like peptide (GALP) is a neuropeptide involved in the regulation of feeding behavior and energy metabolism in mammals. While a weight loss effect of GALP has been reported, its effects on lipid metabolism have not been investigated. The aim of this study was to determine if GALP regulates lipid metabolism in liver and adipose tissue via an action on the sympathetic nervous system. The respiratory exchange ratio of mice administered GALP intracerebroventricularly was lower than that of saline-treated animals, and fatty acid oxidation-related gene mRNA levels were increased in the liver. Even though the respiratory exchange ratio was reduced by GALP, this change was not significant when mice were treated with the sympatholytic drug, guanethidine. Lipolysis-related gene mRNA levels were increased in the adipose tissue of GALP-treated mice compared with saline-treated animals. These results show that GALP stimulates fatty acid β-oxidation in liver and lipolysis in adipose tissue, and suggest that the anti-obesity effect of GALP may be due to anorexigenic actions and improvement of lipid metabolism in peripheral tissues via the sympathetic nervous system.
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Affiliation(s)
- Satoshi Hirako
- Department of Health and Nutrition, University of Human Arts and Sciences, Saitama, Japan
| | - Nobuhiro Wada
- Department of Internal Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Fumiko Takenoya
- Department of Exercise and Sports Physiology, Hoshi University School of Pharmacy and Pharmaceutical Science, Tokyo, Japan
| | - Yoshihiko Izumida
- Department of Internal Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hyounju Kim
- Department of Clinical Dietetics &Human Nutrition, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Yuzuru Iizuka
- Department of Clinical Dietetics &Human Nutrition, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Akiyo Matsumoto
- Department of Clinical Dietetics &Human Nutrition, Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Mai Okabe
- Tokyo Shokuryo Dietitian Academy, Tokyo, Japan
| | - Ai Kimura
- Hoshi University School of Pharmacy and Pharmaceutical Sciences Global Research Center for Innovative Life Science Peptide Drug Innovation, Tokyo, Japan
| | - Mamiko Suzuki
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Satoru Yamanaka
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Seiji Shioda
- Hoshi University School of Pharmacy and Pharmaceutical Sciences Global Research Center for Innovative Life Science Peptide Drug Innovation, Tokyo, Japan
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10
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Fang P, He B, Shi M, Kong G, Dong X, Zhu Y, Bo P, Zhang Z. The regulative effect of galanin family members on link of energy metabolism and reproduction. Peptides 2015; 71:240-9. [PMID: 26188174 DOI: 10.1016/j.peptides.2015.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 06/27/2015] [Accepted: 07/03/2015] [Indexed: 12/22/2022]
Abstract
It is essential for the species survival that an efficient coordination between energy storage and reproduction through endocrine regulation. The neuropeptide galanin, one of the endocrine hormones, can potently coordinate energy metabolism and the activities of hypothalamic-pituitary-gonadal reproductive axis to adjust synthesis and release of metabolic and reproductive hormones in animals and humans. However, few papers have summarized the regulative effect of the galanin family members on the link of energy storage and reproduction as yet. To address this issue, this review attempts to summarize the current information available about the regulative effect of galanin, galanin-like peptide and alarin on the metabolic and reproductive events, with special emphasis on the interactions between galanin and hypothalamic gonadotropin-releasing hormone, pituitary luteinizing hormone and ovarian hormones. This research line will further deepen our understanding of the physiological roles of the galanin family in regulating the link of energy metabolism and reproduction.
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Affiliation(s)
- Penghua Fang
- Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou 225300, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Biao He
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Mingyi Shi
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Guimei Kong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Xiaoyun Dong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
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Lang R, Gundlach AL, Holmes FE, Hobson SA, Wynick D, Hökfelt T, Kofler B. Physiology, signaling, and pharmacology of galanin peptides and receptors: three decades of emerging diversity. Pharmacol Rev 2015; 67:118-75. [PMID: 25428932 DOI: 10.1124/pr.112.006536] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galanin was first identified 30 years ago as a "classic neuropeptide," with actions primarily as a modulator of neurotransmission in the brain and peripheral nervous system. Other structurally-related peptides-galanin-like peptide and alarin-with diverse biologic actions in brain and other tissues have since been identified, although, unlike galanin, their cognate receptors are currently unknown. Over the last two decades, in addition to many neuronal actions, a number of nonneuronal actions of galanin and other galanin family peptides have been described. These include actions associated with neural stem cells, nonneuronal cells in the brain such as glia, endocrine functions, effects on metabolism, energy homeostasis, and paracrine effects in bone. Substantial new data also indicate an emerging role for galanin in innate immunity, inflammation, and cancer. Galanin has been shown to regulate its numerous physiologic and pathophysiological processes through interactions with three G protein-coupled receptors, GAL1, GAL2, and GAL3, and signaling via multiple transduction pathways, including inhibition of cAMP/PKA (GAL1, GAL3) and stimulation of phospholipase C (GAL2). In this review, we emphasize the importance of novel galanin receptor-specific agonists and antagonists. Also, other approaches, including new transgenic mouse lines (such as a recently characterized GAL3 knockout mouse) represent, in combination with viral-based techniques, critical tools required to better evaluate galanin system physiology. These in turn will help identify potential targets of the galanin/galanin-receptor systems in a diverse range of human diseases, including pain, mood disorders, epilepsy, neurodegenerative conditions, diabetes, and cancer.
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Affiliation(s)
- Roland Lang
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Andrew L Gundlach
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Fiona E Holmes
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Sally A Hobson
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - David Wynick
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Tomas Hökfelt
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Barbara Kofler
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
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Fraley GS, Leathley E, Nickols A, Gerometta E, Coombs E, Colton S, Gallemore S, Lindberg A, Kofler B. Alarin 6-25Cys antagonizes alarin-specific effects on food intake and luteinizing hormone secretion. Neuropeptides 2013; 47:37-41. [PMID: 23009720 DOI: 10.1016/j.npep.2012.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 07/17/2012] [Accepted: 08/07/2012] [Indexed: 12/17/2022]
Abstract
Previous data from our labs and from others have demonstrated that intracerebroventricular (ICV) injection of alarin has orexigenic activity and significantly increases plasma luteinizing hormone (LH) secretion in a gonadotropin-releasing hormone (GnRH) dependent manner. The purpose of the current experiments was to determine if the amino acids at the amino-terminal end of the alarin peptide are critical for alarin's effects on reproductive and feeding systems. First, we injected male mice ICV with full-length alarin (Ala1-25) or peptide fragments missing residues at the amino-terminal end (Ala3-25 or Ala6-25 Cys). Neither peptide fragment alone, significantly increased food intake in male mice compared to controls. Second, ICV injection of Ala1-25, but not Ala3-25, significantly (p < 0.01) increased GnRH-mediated LH secretion. Surprisingly, Ala6-25 Cys significantly (p < 0.05) inhibited plasma LH secretion and inhibited Ala1-25 actions. In conclusion, elimination of the first five amino acids of alarin not only abolishes the biological activity of alarin, but becomes an antagonist to alarin-specific effects. Furthermore, Ala6-25 Cys seems to act as a specific antagonist to putative alarin receptors and therefore may be an important tool in identifying alarin-specific receptors.
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Affiliation(s)
- Gregory S Fraley
- Department of Biology & Neuroscience Program, Hope College, Holland, MI 49423, USA.
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13
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Kageyama H, Endo K, Osaka T, Watanabe J, Wang LH, Ito K, Suzuki M, Sakagami J, Takenoya F, Shioda S. Galanin-like peptide (GALP) facilitates thermogenesis via synthesis of prostaglandin E2 by astrocytes in the periventricular zone of the third ventricle. J Mol Neurosci 2013; 50:443-52. [PMID: 23354880 DOI: 10.1007/s12031-013-9952-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 01/02/2013] [Indexed: 11/25/2022]
Abstract
Administration of galanin-like peptide (GALP) leads to a decrease in both total food intake and body weight 24 h after injection, compared to controls. Moreover, GALP induces an increase in core body temperature. To elucidate the mechanism by which GALP exerts its effect on energy homeostasis, urethane-anesthetized rats were intracerebroventricularly injected with GALP or saline, after which oxygen consumption, heart rate, and body temperature were monitored for 4 h. In some cases, animals were also pretreated with the cyclooxygenase (COX) inhibitor, diclofenac, via intracerebroventricular (i.c.v.) or intravenous (i.v.) injection. c-Fos expression in the brain was also examined after injection of GALP, and the levels of COX and prostaglandin E(2) synthetase (PGES) mRNA in primary cultured astrocytes treated with GALP were analyzed by using qPCR. The i.c.v. injection of GALP caused biphasic thermogenesis, an effect which could be blocked by pretreatment with centrally (i.c.v.), but not peripherally (i.v.) administered diclofenac. c-Fos immunoreactivity was observed in astrocytes in the periventricular zone of the third ventricle. GALP treatment also increased COX-2 and cytosolic PGES, but not COX-1, microsomal PGES-1, or microsomal PGES-2 mRNA levels in cultured astrocytes. We, therefore, suggest that GALP elicits thermogenesis via a prostaglandin E(2)-mediated pathway in astrocytes of the central nervous system.
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Affiliation(s)
- Haruaki Kageyama
- Faculty of Health Care, Kiryu University, Midori City, Gunma, 379-2392, Japan
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14
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Anderson ME, Runesson J, Saar I, Langel U, Robinson JK. Galanin, through GalR1 but not GalR2 receptors, decreases motivation at times of high appetitive behavior. Behav Brain Res 2012; 239:90-3. [PMID: 23142608 DOI: 10.1016/j.bbr.2012.10.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 01/20/2023]
Abstract
Galanin is a 29/30-amino acid long neuropeptide that has been implicated in many physiological and behavioral functions. Previous research has shown that i.c.v. administration of galanin strongly stimulates food intake in sated rats when food is freely available, but fails to stimulate this consumption when an operant response requirement is present. Using fixed ratio (FR) schedules, we sought to further clarify galanin's role in motivated behavior by administering galanin i.c.v. to rats working on fixed ratio schedules requiring either a low work condition (FR1) or higher work conditions (FR>1) to obtain a 0.2% saccharin reward. Rats in the FR>1 group were assigned to either an FR3, FR5 or FR7 schedule of reinforcement. The rate of reinforcement decreased for only the FR>1 group as compared to saline controls. Furthermore, injections of GalR1 receptor agonist M617 led to a similar, marginally significant decrease in the number of reinforcers received in the FR>1 condition, but a decrease was not seen after injections of GalR2 receptor agonist M1153. Taken together, these results show that galanin may be playing a role in decreasing motivation at times of high appetitive behavior, and that this effect is likely mediated by the GalR1 receptor.
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Affiliation(s)
- Maria E Anderson
- Department of Psychology, Stony Brook University, Stony Brook, NY 11794, USA
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Fang P, Yu M, Shi M, Zhang Z, Sui Y, Guo L, Bo P. Galanin peptide family as a modulating target for contribution to metabolic syndrome. Gen Comp Endocrinol 2012; 179:115-20. [PMID: 22909974 DOI: 10.1016/j.ygcen.2012.07.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 07/25/2012] [Accepted: 07/27/2012] [Indexed: 12/23/2022]
Abstract
Metabolic syndrome (MetS) is defined as abdominal central obesity, atherogenic dyslipidemia, insulin resistance, glucose intolerance and hypertension. The rapid increasing prevalence of MetS and the consequent diseases, such as type 2 diabetes mellitus and cardiovascular disorder, are becoming a global epidemic health problem. Despite considerable research into the etiology of this complex disease, the precise mechanism underlying MetS and the association of this complex disease with the development of type 2 diabetes mellitus and increased cardiovascular disease remains elusive. Therefore, researchers continue to actively search for new MetS treatments. Recent animal studies have indicated that the galanin peptide family of peptides may increase food intake, glucose intolerance, fat preference and the risk for obesity and dyslipidemia while decreasing insulin resistance and blood pressure, which diminishes the probability of type 2 diabetes mellitus and hypertension. To date, however, few papers have summarized the role of the galanin peptide family in modulating MetS. Through a summary of available papers and our recent studies, this study reviews the updated evidences of the effect that the galanin peptide family has on the clustering of MetS components, including obesity, dyslipidemia, insulin resistance and hypertension. This line of research will further deepen our understanding of the relationship between the galanin peptide family and the mechanisms underlying MetS, which will help develop new therapeutic strategies for this complex disease.
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Affiliation(s)
- Penghua Fang
- Department of Physiology, Hanlin College, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, China
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Fang P, Yu M, Guo L, Bo P, Zhang Z, Shi M. Galanin and its receptors: a novel strategy for appetite control and obesity therapy. Peptides 2012; 36:331-9. [PMID: 22664322 DOI: 10.1016/j.peptides.2012.05.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/24/2012] [Accepted: 05/24/2012] [Indexed: 12/14/2022]
Abstract
The rapid increase in the prevalence of overweight and obesity is becoming an important health problem. Overweight and obesity may cause several metabolic complications, including type 2 diabetes mellitus, hyperlipidemia, high cholesterol, coronary artery disease as well as hypertension. Prevention and treatment of obesity will benefit the treatment of these related diseases. Current strategies for treatment of obesity are not adequately effective and are frequently companied with many side effects. Thus, new ways to treat obesity are urgently needed. Galanin is undoubtedly involved in the regulation of food intake and body weight. The aim of this review is to provide up-to-date knowledge concerning the roles of central and peripheral galanin as well as its receptors in the regulation of metabolism, obesity and appetite. We also highlight the mechanisms of galanin and its receptors in experimental obesity, trying to establish a novel anti-obesity strategy.
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Affiliation(s)
- Penghua Fang
- Department of Physiology, Yangzhou University, Yangzhou, Jiangsu, China
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17
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Hypothalamic neuropeptides and the regulation of appetite. Neuropharmacology 2012; 63:18-30. [PMID: 22369786 DOI: 10.1016/j.neuropharm.2012.02.004] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 12/23/2011] [Accepted: 02/07/2012] [Indexed: 12/24/2022]
Abstract
Neuropeptides released by hypothalamic neurons play a major role in the regulation of feeding, acting both within the hypothalamus, and at other appetite regulating centres throughout the brain. Where classical neurotransmitters signal only within synapses, neuropeptides diffuse over greater distances affecting both nearby and distant neurons expressing the relevant receptors, which are often extrasynaptic. As well as triggering a behavioural output, neuropeptides also act as neuromodulators: altering the response of neurons to both neurotransmitters and circulating signals of nutrient status. The mechanisms of action of hypothalamic neuropeptides with established roles in feeding, including melanin-concentrating hormone (MCH), the orexins, α-melanocyte stimulating hormone (α-MSH), agouti-gene related protein (AgRP), neuropeptide Y, and oxytocin, are reviewed in this article, with emphasis laid on both their effects on appetite regulating centres throughout the brain, and on examining the evidence for their physiological roles. In addition, evidence for the involvement of several putative appetite regulating hypothalamic neuropeptides is assessed including, ghrelin, cocaine and amphetamine-regulated transcript (CART), neuropeptide W and the galanin-like peptides. This article is part of a Special Issue entitled 'Central control of Food Intake'.
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Webling KEB, Runesson J, Bartfai T, Langel Ü. Galanin receptors and ligands. Front Endocrinol (Lausanne) 2012; 3:146. [PMID: 23233848 PMCID: PMC3516677 DOI: 10.3389/fendo.2012.00146] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 11/08/2012] [Indexed: 12/13/2022] Open
Abstract
The neuropeptide galanin was first discovered 30 years ago. Today, the galanin family consists of galanin, galanin-like peptide (GALP), galanin-message associated peptide (GMAP), and alarin and this family has been shown to be involved in a wide variety of biological and pathological functions. The effect is mediated through three GPCR subtypes, GalR1-3. The limited number of specific ligands to the galanin receptor subtypes has hindered the understanding of the individual effects of each receptor subtype. This review aims to summarize the current data of the importance of the galanin receptor subtypes and receptor subtype specific agonists and antagonists and their involvement in different biological and pathological functions.
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Affiliation(s)
- Kristin E. B. Webling
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
- *Correspondence: Kristin E. B. Webling, Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm University, Svante Arrheniusv. 21A, 10691 Stockholm, Sweden. e-mail:
| | - Johan Runesson
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
| | - Tamas Bartfai
- Molecular and Integrative Neurosciences Department, The Scripps Research InstituteLa Jolla, CA, USA
| | - Ülo Langel
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
- Institute of Technology, University of TartuTartu, Estonia
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Boughton CK, Patterson M, Bewick GA, Tadross JA, Gardiner JV, Beale KEL, Chaudery F, Hunter G, Busbridge M, Leavy EM, Ghatei MA, Bloom SR, Murphy KG. Alarin stimulates food intake and gonadotrophin release in male rats. Br J Pharmacol 2011; 161:601-13. [PMID: 20880399 DOI: 10.1111/j.1476-5381.2010.00893.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Alarin is a recently discovered member of the galanin peptide family encoded by a splice variant of galanin-like peptide (GALP) mRNA. Galanin and GALP regulate energy homeostasis and reproduction. We therefore investigated the effects of alarin on food intake and gonadotrophin release. EXPERIMENTAL APPROACH Alarin was administered into the third cerebral ventricle (i.c.v.) of rats, and food intake or circulating hormone levels were measured. The effect of alarin on the hypothalamo-pituitary-gonadal axis was investigated in vitro using hypothalamic and anterior pituitary explants, and immortalized cell lines. Receptor binding assays were used to determine whether alarin binds to galanin receptors. KEY RESULTS The i.c.v. administration of alarin (30 nmol) to ad libitum fed male rats significantly increased acute food intake to 500%, and plasma luteinizing hormone (LH) levels to 170% of responses to saline. In vitro, 100 nM alarin stimulated neuropeptide Y (NPY) and gonadotrophin-releasing hormone (GnRH) release from hypothalamic explants from male rats, and 1000 nM alarin increased GnRH release from GT1-7 cells. In vivo, pretreatment with the GnRH receptor antagonist cetrorelix prevented the increase in plasma LH levels observed following i.c.v. alarin administration. Receptor binding studies confirmed alarin did not bind to any known galanin receptor, or compete with radiolabelled galanin for hypothalamic binding sites. CONCLUSIONS AND IMPLICATIONS These results suggest alarin is a novel orexigenic peptide, and that it increases circulating LH levels via hypothalamic GnRH. Further work is required to identify the receptor(s) mediating the biological effects of alarin.
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Affiliation(s)
- C K Boughton
- Department of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London, UK
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Shiba K, Kageyama H, Takenoya F, Shioda S. Galanin-like peptide and the regulation of feeding behavior and energy metabolism. FEBS J 2011; 277:5006-13. [PMID: 21126314 DOI: 10.1111/j.1742-4658.2010.07933.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hypothalamic neuropeptides modulate physiological activity via G protein-coupled receptors (GPCRs). Galanin-like peptide (GALP) is a 60 amino acid neuropeptide that was originally isolated from porcine hypothalamus using a binding assay for galanin receptors, which belong to the GPCR family. GALP is mainly produced in neurons in the hypothalamic arcuate nucleus. GALP-containing neurons form neuronal networks with several other types of peptide-containing neurons and then regulate feeding behavior and energy metabolism. In rats, the central injection of GALP produces a dichotomous action that involves transient hyperphasia followed by hypophasia and a reduction in body weight, whereas, in mice, it has only one action that reduces both food intake and body weight. In the present minireview, we discuss current evidence regarding the function of GALP, particularly in relation to feeding and energy metabolism. We also examine the effects of GALP activity on food intake, body weight and locomotor activity after intranasal infusion, a clinically viable mode of delivery. We conclude that GALP may be of therapeutic value for obesity and life-style-related diseases in the near future.
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Affiliation(s)
- Kanako Shiba
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
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Lawrence C, Fraley GS. Galanin-like peptide (GALP) is a hypothalamic regulator of energy homeostasis and reproduction. Front Neuroendocrinol 2011; 32:1-9. [PMID: 20558195 PMCID: PMC2950899 DOI: 10.1016/j.yfrne.2010.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 04/26/2010] [Accepted: 06/09/2010] [Indexed: 12/30/2022]
Abstract
Galanin-like peptide (GALP) was discovered in 1999 in the porcine hypothalamus and was found to be a 60 amino acid neuropeptide. GALP shares sequence homology to galanin (1-13) in position 9-21 and can bind to, as well as activate, the three galanin receptor subtypes (GalR1-3). GALP-expressing cells are limited, and are mainly found in the arcuate nucleus of the hypothalamus (ARC) and the posterior pituitary. GALP-positive neurons in the ARC project to several brain regions where they appear to make contact with multiple neuromodulators. These neuromodulators are involved in the regulation of energy homeostasis and reproduction, anatomical evidence that suggests a role for GALP in these physiological functions. In support of this idea, GALP gene expression is regulated by several factors that reflect metabolic state including the metabolic hormones leptin and insulin, thyroid hormones, and blood glucose. Considerable evidence now exists to support the hypothesis that GALP has a role in the regulation of energy homeostasis and reproduction; and, that GALP's role may be independent of the known galanin receptors. In this review, we (1) provide an overview of the distribution of GALP, and discuss the potential relationship between GALP and other neuromodulators of energy homeostasis and reproduction, (2) discuss the metabolic factors that regulate GALP expression, (3) review the evidence for the role of GALP in energy homeostasis and reproduction, (4) discuss the potential downstream mediators and mechanisms underlying GALP's effects, and (5) discuss the possibility that GALP may mediate its effects via an as yet unidentified GALP-specific receptor.
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Shioda S, Kageyama H, Takenoya F, Shiba K. Galanin-like peptide: a key player in the homeostatic regulation of feeding and energy metabolism? Int J Obes (Lond) 2010; 35:619-28. [PMID: 20938442 DOI: 10.1038/ijo.2010.202] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The hypothalamus has a critical role in the regulation of feeding behavior, energy metabolism and reproduction. Galanin-like peptide (GALP), a novel 60 amino-acid peptide with a nonamidated C-terminus, was first discovered in porcine hypothalamus. GALP is mainly produced in the hypothalamic arcuate nucleus and is involved in the regulation of feeding behavior and energy metabolism, with GALP-containing neurons forming networks with several feeding-regulating peptide-containing neurons. The effects of GALP on food intake and body weight are complex. In rats, the central effect of GALP is to first stimulate and then reduce food intake, whereas in mice, GALP has an anorectic function. Furthermore, GALP regulates plasma luteinizing hormone levels through activation of gonadotropin-releasing hormone-producing neurons, suggesting that it is also involved in the reproductive system. This review summarizes the research on these topics and discusses current evidence regarding the function of GALP, particularly in relation to feeding and energy metabolism. We also discuss the effects of GALP activity on food intake, body weight and locomotor activity after intranasal infusion, a clinically viable mode of delivery.
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Affiliation(s)
- S Shioda
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
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23
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Galanin-Like Peptide: Neural Regulator of Energy Homeostasis and Reproduction. EXPERIENTIA SUPPLEMENTUM 2010; 102:263-80. [DOI: 10.1007/978-3-0346-0228-0_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Lawrence CB. Galanin-like peptide modulates energy balance by affecting inflammatory mediators? Physiol Behav 2009; 97:515-9. [DOI: 10.1016/j.physbeh.2009.02.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/16/2009] [Accepted: 02/18/2009] [Indexed: 12/25/2022]
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Taylor A, Madison F, Fraley G. Galanin-like peptide stimulates feeding and sexual behavior via dopaminergic fibers within the medial preoptic area of adult male rats. J Chem Neuroanat 2009; 37:105-11. [DOI: 10.1016/j.jchemneu.2008.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 12/08/2008] [Accepted: 12/09/2008] [Indexed: 02/07/2023]
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26
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Whitelaw CM, Robinson JE, Chambers GB, Hastie P, Padmanabhan V, Thompson RC, Evans NP. Expression of mRNA for galanin, galanin-like peptide and galanin receptors 1–3 in the ovine hypothalamus and pituitary gland: effects of age and gender. Reproduction 2009; 137:141-50. [DOI: 10.1530/rep-08-0266] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The neurotransmitters/neuromodulators galanin (GAL) and galanin-like peptide (GALP) are known to operate through three G protein-coupled receptors, GALR1, GALR2 and GALR3. The aim of this study was to investigate changes in expression of mRNA for galanin, GALP and GALR1–3 in the hypothalamus and pituitary gland, of male and female sheep, to determine how expression changed in association with growth and the attainment of reproductive competence. Tissue samples from the hypothalami and pituitary glands were analysed from late foetal and pre-pubertal lambs and adult sheep. Although mRNA for galanin and GALR1-3 was present in both tissues, at all ages and in both genders, quantification of GALP mRNA was not possible due to its low levels of expression. mRNA expression for both galanin and its receptors was seen to change significantly in both tissues as a function of age. Specifically, hypothalamic galanin mRNA expression increased with age in the male, but decreased with age in the female pituitary gland. mRNA expression for all receptors increased between foetal and pre-pubertal age groups and decreased significantly between pre-pubertal and adult animals. The results indicate that the expression of mRNA for galanin and its receptors changes dynamically with age and those significant differences exist with regard to tissue type and gender. These changes suggest that galaninergic neuroendocrine systems could be involved in the regulation of ovine growth and or the development of reproductive competence. The roles played by these systems in the sheep, however, may differ from other species, in particular the neuroendocrine link between nutrition and reproduction and GALR1's role in pituitary signalling.
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Abstract
Galanin-like peptide (GALP) is a neuropeptide that has complex actions on energy balance, producing orexigenic effects in the short term in rats but anorexigenic and febrile effects over the longer term in rats and mice. GALP is thought to promote feeding via neuropeptide Y and orexin neurons, but the mediators of the anorexia are unknown. However, the anorexic and febrile actions of GALP are similar in magnitude and profile to those seen after central injections of the cytokine IL-1. Thus, the aim of this study was to test the hypothesis that IL-1 mediates the effects of GALP on energy balance. Intracerebroventricular injection of GALP (1.5 nmol) in male Sprague-Dawley rats stimulated production of IL-1alpha and IL-1beta protein in macrophages and/or microglia in selected brain areas, including the meninges, and periventricular brain regions. Intracerebroventricular injection of GALP in rats stimulated food intake over 1 h but decreased feeding and body weight at 24 h and caused a rise in core body temperature over 8 h. Coinfusion of the IL-1 receptor antagonist had no effect on the GALP-induced orexigenic response but significantly reduced the longer-term actions of GALP observed at 24 h and its effect on body temperature. Furthermore, the actions of GALP on feeding, body weight, and body temperature were significantly reduced in IL-1alpha/beta-, IL-1beta-, or IL-1 type I receptor (IL-1RI)-deficient mice. These data suggest that GALP induces expression of IL-1 in the brain, and its anorexic and febrile actions are mediated by this cytokine acting via IL-1 type I receptor.
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Affiliation(s)
- Pui-Sin Man
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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Dungan Lemko HM, Clifton DK, Steiner RA, Fraley GS. Altered response to metabolic challenges in mice with genetically targeted deletions of galanin-like peptide. Am J Physiol Endocrinol Metab 2008; 295:E605-12. [PMID: 18775887 PMCID: PMC2536739 DOI: 10.1152/ajpendo.90425.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Galanin-like peptide (GALP) is expressed in the arcuate nucleus and is implicated in the neuroendocrine regulation of metabolism and reproduction. To investigate the physiological significance of GALP, we generated and characterized a strain of mice with a genetically targeted deletion in the GALP gene [GALP knockout (KO) mice]. We report that GALP KO mice have a subtle, but notable, metabolic phenotype that becomes apparent during adaptation to changes in nutrition. GALP KO mice are indistinguishable from wild-type (WT) controls in virtually all aspects of growth, sexual development, body weight, food and water consumption, and motor behaviors, when they are allowed unlimited access to standard rodent chow. However, GALP KO mice have an altered response to changes in diet. 1) Male GALP KO mice consumed less food during refeeding after a fast than WT controls (P < 0.01). 2) GALP KO mice of both sexes gained less weight on a high-fat diet than WT controls (P < 0.01), despite both genotypes having consumed equal amounts of food. We conclude that although GALP signaling may not be essential for the maintenance of energy homeostasis under steady-state nutritional conditions, GALP may play a role in readjusting energy balance under changing nutritional circumstances.
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Man PS, Lawrence CB. Galanin-like peptide: a role in the homeostatic regulation of energy balance? Neuropharmacology 2008; 55:1-7. [PMID: 18538801 DOI: 10.1016/j.neuropharm.2008.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 04/07/2008] [Accepted: 04/09/2008] [Indexed: 11/23/2022]
Abstract
Galanin-like peptide (GALP) is a neuropeptide that has been proposed to play a role in the regulation of food intake behaviour and body weight. However, the actions of GALP on energy balance are complex. In rats, it appears to impel both appetite stimulating and suppressing effects, whereas in mice, the only effect is a reduction in food intake. Thus, it is currently unclear whether GALP is important in the homeostatic regulation of energy balance, or if it produces effects on appetite and body weight by non-specific actions. This review discusses current evidence of the role of GALP with respect to energy balance, and the mechanisms involved in its regulation. We describe recent evidence that suggests that GALP may elicit differential effects in different rodent species. Furthermore, we provide an insight into a potential novel role for GALP in inflammation, and discuss how this may relate to the non-homeostatic regulation of energy balance.
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Affiliation(s)
- Pui-Sin Man
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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Man PS, Lawrence CB. The effects of galanin-like peptide on energy balance, body temperature and brain activity in the mouse and rat are independent of the GALR2/3 receptor. J Neuroendocrinol 2008; 20:128-37. [PMID: 18081561 PMCID: PMC3306895 DOI: 10.1111/j.1365-2826.2007.01625.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Galanin-like peptide (GALP) is a neuropeptide that is thought to act on the galanin receptors GALR1, GALR2 and GALR3. In rats, i.c.v. injection of GALP has dichotomous actions on energy balance, stimulating feeding over the first hour, but reducing food intake and body weight at 24 h, as well as causing an increase in core body temperature. In mice, GALP only induces an anorexic action, and its effects on core body temperature are unknown. One aim of the present study was to determine the effects of GALP on core body temperature in mice. Intracerebroventricular injection of GALP into conscious mice had no effect on feeding over 1 h, but caused a significant reduction in food intake and body weight at 24 h. It also caused an immediate drop in core body temperature, which was followed by an increase in body temperature. To understand these different effects of GALP on energy balance in mice compared to rats, and to determine the involvement of GALR2 and GALR3, immunohistochemistry was performed to localise c-Fos, a marker of cell activation. Intracerebroventricular injection of GALP induced c-Fos expression in the parenchyma surrounding the ventricles, the ventricular ependymal cells and the meninges in mice and rats. GALP also induced c-Fos expression in the supraoptic nucleus, dorsomedial hypothalamic nucleus, lateral hypothalamus and nucleus tractus solitarius in rats but not in mice. Central administration of a GALR2/3 agonist in rats did not induce c-Fos in any of the brain regions that expressed this protein after GALP injection, and had no effect on food intake, body weight and body temperature in rats or mice. These data suggest that GALP induces differential effects on energy balance and brain activity in mice compared to rats, which are unlikely to be due to activation of the GALR2 or GALR3 receptor.
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MESH Headings
- Animals
- Animals, Newborn
- Body Temperature/drug effects
- Body Weight/drug effects
- Brain/drug effects
- Brain/metabolism
- Brain/physiology
- Cells, Cultured
- Eating/drug effects
- Energy Metabolism/drug effects
- Galanin/administration & dosage
- Galanin/pharmacology
- Galanin-Like Peptide/administration & dosage
- Galanin-Like Peptide/pharmacology
- Homeostasis/drug effects
- Injections, Intraventricular
- Male
- Mice
- Mice, Inbred C57BL
- Peptide Fragments/administration & dosage
- Peptide Fragments/pharmacology
- Proto-Oncogene Proteins c-fos/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Galanin, Type 2/agonists
- Receptor, Galanin, Type 2/physiology
- Receptor, Galanin, Type 3/agonists
- Receptor, Galanin, Type 3/physiology
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Affiliation(s)
- Pui-Sin Man
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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31
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Dungan HM, Gottsch ML, Zeng H, Gragerov A, Bergmann JE, Vassilatis DK, Clifton DK, Steiner RA. The role of kisspeptin-GPR54 signaling in the tonic regulation and surge release of gonadotropin-releasing hormone/luteinizing hormone. J Neurosci 2007; 27:12088-95. [PMID: 17978050 PMCID: PMC6673361 DOI: 10.1523/jneurosci.2748-07.2007] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Revised: 08/14/2007] [Accepted: 09/13/2007] [Indexed: 12/24/2022] Open
Abstract
The Kiss1 gene codes for kisspeptin, which binds to GPR54, a G-protein-coupled receptor. Kisspeptin and GPR54 are expressed in discrete regions of the forebrain, and they have been implicated in the neuroendocrine regulation of reproduction. Kiss1-expressing neurons are thought to regulate the secretion of gonadotropin-releasing hormone (GnRH) and thus coordinate the estrous cycle in rodents; however, the precise role of kisspeptin-GPR54 signaling in the regulation of gonadotropin secretion is unknown. In this study, we used female mice with deletions in the GPR54 gene [GPR54 knock-outs (KOs)] to test the hypothesis that kisspeptin-GPR54 signaling provides the drive necessary for tonic GnRH/luteinizing hormone (LH) release. We predicted that tonic GnRH/LH secretion would be disrupted in GPR54 KOs and that such animals would be incapable of showing a compensatory rise in LH secretion after ovariectomy. As predicted, we found that GPR54 KO mice do not exhibit a postovariectomy rise in LH, suggesting that tonic GnRH secretion is disrupted in the absence of kisspeptin-GPR54 signaling. We also postulated that kisspeptin-GPR54 signaling is critical for the generation of the estradiol (E)-induced GnRH/LH surge and thus E should be incapable of inducing an LH surge in the absence of GPR54. However, we found that E induced Fos expression in GnRH neurons and produced a GnRH-dependent LH surge in GPR54 KOs. Thus, in mice, kisspeptin-GPR54 signaling is required for the tonic stimulation of GnRH/LH secretion but is not required for generating the E-induced GnRH/LH surge.
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Affiliation(s)
| | - Michelle L. Gottsch
- Obstetrics and Gynecology, University of Washington, Seattle, Washington 98195
| | - Hongkui Zeng
- Allen Brain Institute, Seattle, Washington 98101
| | | | | | | | - Donald K. Clifton
- Obstetrics and Gynecology, University of Washington, Seattle, Washington 98195
| | - Robert A. Steiner
- Departments of Physiology and Biophysics and
- Obstetrics and Gynecology, University of Washington, Seattle, Washington 98195
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32
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Kauffman AS, Park JH, McPhie-Lalmansingh AA, Gottsch ML, Bodo C, Hohmann JG, Pavlova MN, Rohde AD, Clifton DK, Steiner RA, Rissman EF. The kisspeptin receptor GPR54 is required for sexual differentiation of the brain and behavior. J Neurosci 2007; 27:8826-35. [PMID: 17699664 PMCID: PMC6672184 DOI: 10.1523/jneurosci.2099-07.2007] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GPR54 is a G-protein-coupled receptor, which binds kisspeptins and is widely expressed throughout the brain. Kisspeptin-GPR54 signaling has been implicated in the regulation of pubertal and adulthood gonadotropin-releasing hormone (GnRH) secretion, and mutations or deletions of GPR54 cause hypogonadotropic hypogonadism in humans and mice. Other reproductive roles for kisspeptin-GPR54 signaling, including the regulation of developmental GnRH secretion or sexual behavior in adults, have not yet been explored. Using adult wild-type (WT) and GPR54 knock-out (KO) mice, we first tested whether kisspeptin-GPR54 signaling is necessary for male and female sexual behaviors. We found that hormone-replaced gonadectomized GPR54 KO males and females displayed appropriate gender-specific adult sexual behaviors. Next, we examined whether GPR54 signaling is required for proper display of olfactory-mediated partner preference behavior. Testosterone-treated WT males preferred stimulus females rather than males, whereas similarly treated WT females and GPR54 KO males showed no preference for either sex. Because olfactory preference is sexually dimorphic and organized during development by androgens, we assessed whether GPR54 signaling is essential for sexual differentiation of other sexually dimorphic traits. Interestingly, adult testosterone-treated GPR54 KO males displayed "female-like" numbers of tyrosine hydroxylase-immunoreactive and Kiss1 mRNA-containing neurons in the anteroventral periventricular nucleus and likewise possessed fewer motoneurons in the spino-bulbocavernosus nucleus than did WT males. Our findings indicate that kisspeptin-GPR54 signaling is not required for male or female copulatory behavior, provided there is appropriate adulthood hormone replacement. However, GPR54 is necessary for proper male-like development of several sexually dimorphic traits, likely by regulating GnRH-mediated androgen secretion during "critical windows" in perinatal development.
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Affiliation(s)
- Alexander S Kauffman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908, USA.
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33
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Gragerov A, Horie K, Pavlova M, Madisen L, Zeng H, Gragerova G, Rhode A, Dolka I, Roth P, Ebbert A, Moe S, Navas C, Finn E, Bergmann J, Vassilatis DK, Pavlakis GN, Gaitanaris GA. Large-scale, saturating insertional mutagenesis of the mouse genome. Proc Natl Acad Sci U S A 2007; 104:14406-11. [PMID: 17720809 PMCID: PMC1964832 DOI: 10.1073/pnas.0700608104] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We describe the construction of a large-scale, orderly assembly of mutant ES cells, generated with retroviral insertions and having mutational coverage in >90% of mouse genes. We also describe a method for isolating ES cell clones with mutations in specific genes of interest from this library. This approach, which combines saturating random mutagenesis with targeted selection of mutations in the genes of interest, was successfully applied to the gene families of G protein-coupled receptors (GPCRs) and nuclear receptors. Mutant mouse strains in 60 different GPCRs were generated. Applicability of the technique for the GPCR genes, which on average represent fairly small targets for insertional mutagenesis, indicates the general utility of our approach for the rest of the genome. The method also allows for increased scale and automation for the large-scale production of mutant mice, which could substantially expedite the functional characterization of the mouse genome.
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Affiliation(s)
- Alexander Gragerov
- Omeros Corporation, 1420 Fifth Avenue, Suite 2600, Seattle, WA 98101, USA.
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34
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Rich N, Reyes P, Reap L, Goswami R, Fraley GS. Sex differences in the effect of prepubertal GALP infusion on growth, metabolism and LH secretion. Physiol Behav 2007; 92:814-23. [PMID: 17632189 PMCID: PMC2692297 DOI: 10.1016/j.physbeh.2007.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 05/13/2007] [Accepted: 06/06/2007] [Indexed: 10/23/2022]
Abstract
The hypothalamic neuropeptide, galanin-like peptide (GALP), is known to have an effect on energy expenditure and reproduction in adult male rats, but little work has been done on prepubertal rats. We hypothesized that hypothalamic GALP is involved in physiological changes associated with the onset of puberty. To test this hypothesis, we first determined the postnatal ontogeny of GALP gene expression via in situ hybridization of developing male and female rat pups through adulthood. GALP gene expression was not observed in either male or female rat pups until after postnatal day (PND) 10 and did not reach adult-like levels until after weaning (PND25). To determine if exogenous GALP could induce the onset of puberty, PND25 male and female rats were implanted with lateral ventricular cannulas connected to an osmotic minipump that delivered either GALP or vehicle. GALP infusion significantly (p<0.05) increased body weight, food intake, and metabolic rate in male but not female rats compared to control infusion. After 2 weeks, GALP infusion had no significant effect on the onset of puberty, percent body fat, nor plasma levels of insulin, FSH or gonadal steroids in either sex; however, GALP did significantly (p<0.05) increase plasma levels of LH and leptin in male but not female rats and increased plasma growth hormone (GH) in both sexes. Our observations further demonstrate a sex difference in GALP responsiveness in prepubertal rats. These data suggest that GALP may be involved with the prepubertal increase in circulating leptin, LH, and GH resulting in an increase in metabolic rate and lean growth associated with puberty.
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Affiliation(s)
- N Rich
- Biology Department, Hope College, 35 East 12th Street, Schaap Science Center 3065, Holland, MI 49423, United States
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35
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Mao C, Tili EG, Dose M, Haks MC, Bear SE, Maroulakou I, Horie K, Gaitanaris GA, Fidanza V, Ludwig T, Wiest DL, Gounari F, Tsichlis PN. Unequal Contribution of Akt Isoforms in the Double-Negative to Double-Positive Thymocyte Transition. THE JOURNAL OF IMMUNOLOGY 2007; 178:5443-53. [PMID: 17442925 DOI: 10.4049/jimmunol.178.9.5443] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Pre-TCR signals regulate the transition of the double-negative (DN) 3 thymocytes to the DN4, and subsequently to the double-positive (DP) stage. In this study, we show that pre-TCR signals activate Akt and that pharmacological inhibition of the PI3K/Akt pathway, or combined ablation of Akt1 and Akt2, and to a lesser extent Akt1 and Akt3, interfere with the differentiation of DN3 and the accumulation of DP thymocytes. Combined ablation of Akt1 and Akt2 inhibits the proliferation of DN4 cells, while combined ablation of all Akt isoforms also inhibits the survival of all the DN thymocytes. Finally, the combined ablation of Akt1 and Akt2 inhibits the survival of DP thymocytes. Constitutively active Lck-Akt1 transgenes had the opposite effects. We conclude that, following their activation by pre-TCR signals, Akt1, Akt2, and, to a lesser extent, Akt3 promote the transition of DN thymocytes to the DP stage, in part by enhancing the proliferation and survival of cells undergoing beta-selection. Akt1 and Akt2 also contribute to the differentiation process by promoting the survival of the DP thymocytes.
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Affiliation(s)
- Changchuin Mao
- Molecular Oncology Research Institute, Tufts-New England Medical Center, 750 Washington Street, Boston, MA 02111, USA
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36
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Bailey KR, Pavlova MN, Rohde AD, Hohmann JG, Crawley JN. Galanin receptor subtype 2 (GalR2) null mutant mice display an anxiogenic-like phenotype specific to the elevated plus-maze. Pharmacol Biochem Behav 2007; 86:8-20. [PMID: 17257664 PMCID: PMC1853242 DOI: 10.1016/j.pbb.2006.11.024] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Revised: 11/14/2006] [Accepted: 11/20/2006] [Indexed: 01/31/2023]
Abstract
The neuropeptide galanin has been implicated in anxiety-related behaviors, cognition, analgesia, and feeding in rodents. Neuromodulatory actions of galanin are mediated by three G-protein coupled receptors, GalR1, GalR2, and GalR3. The present study investigates the role of the GalR2 receptor by evaluating behavioral phenotypes of mice with a targeted mutation in the GalR2 gene. A three-tiered behavioral phenotyping approach first examined control measures of general health, body weight, neurological reflexes, sensory abilities and motor function. Mice were then assessed on several tests for cognitive and anxiety-like behaviors. GalR2 null mutants and heterozygotes were not significantly different from wildtype littermates on two cognitive tests previously shown to be sensitive to galanin manipulation: acquisition of the Morris water maze spatial task, and trace cued and contextual fear conditioning, an emotional learning and memory task. Two independent cohorts of GalR2 null mutant mice demonstrated an anxiogenic-like phenotype in the elevated plus-maze. No genotype differences were detected on several other measures of anxiety-like behavior. The discovery of an anxiogenic phenotype specific to the elevated plus-maze, similar to findings in GalR1 null mutants, highlights the potential therapeutic efficacy of targeting GalR1 and GalR2 receptors in treating anxiety disorders.
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37
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Castellano JM, Navarro VM, Fernández-Fernández R, Roa J, Vigo E, Pineda R, Steiner RA, Aguilar E, Pinilla L, Tena-Sempere M. Effects of galanin-like peptide on luteinizing hormone secretion in the rat: sexually dimorphic responses and enhanced sensitivity at male puberty. Am J Physiol Endocrinol Metab 2006; 291:E1281-9. [PMID: 16849629 DOI: 10.1152/ajpendo.00130.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reproductive function is exquisitely sensitive to adequacy of nutrition and fuel reserves, through mechanisms that are yet to be completely elucidated. Galanin-like peptide (GALP) has recently emerged as another neuropeptide link that couples reproduction and metabolism. However, although the effects of GALP on luteinizing hormone (LH) secretion have been studied, no systematic investigation on how these responses might differ along sexual maturation and between sexes has been reported. Moreover, the influence of metabolic status and potential interplay with other relevant neurotransmitters controlling LH secretion remain ill defined. These facets of GALP physiology were addressed herein. Intracerebral injection of GALP to male rats induced a dose-dependent increase in serum LH levels, the magnitude of which was significantly greater in pubertal than in adult males. In contrast, negligible LH responses to GALP were detected in pubertal or adult female rats at diestrus. Neonatal androgen treatment to females failed to "masculinize" the pattern of LH response to GALP. In addition, metabolic stress by short-term fasting did not prevent but rather amplified LH responses to GALP in pubertal males, whereas these responses were abrogated by pharmacological inhibition of nitric oxide synthesis. We conclude that the ability of GALP to evoke LH secretion is sexually differentiated, with maximal responses at male puberty, a phenomenon which was not reverted by manipulation of sex steroid milieu during the critical neonatal period and was sensitive to metabolic stress. This state of LH hyperresponsiveness may prove relevant for the mechanisms relaying metabolic status to the reproductive axis in male puberty.
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Affiliation(s)
- J M Castellano
- Dept. of Cell Biology, Physiology, and Immunology, University of Córdoba, Avda. Menéndez Pidal, 14004 Córdoba, Spain
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38
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Takenoya F, Guan JL, Kato M, Sakuma Y, Kintaka Y, Kitamura Y, Kitamura S, Okuda H, Takeuchi M, Kageyama H, Shioda S. Neural interaction between galanin-like peptide (GALP)- and luteinizing hormone-releasing hormone (LHRH)-containing neurons. Peptides 2006; 27:2885-93. [PMID: 16793173 DOI: 10.1016/j.peptides.2006.05.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
Galanin-like peptide (GALP), commonly known as an appetite-regulating peptide, has been shown to increase plasma luteinizing hormone (LH) through luteinizing hormone-releasing hormone (LHRH). This led us to investigate, using both light and electron microscopy, whether GALP-containing neurons in the rat brain make direct inputs to LHRH-containing neurons. As LHRH-containing neurons are very difficult to demonstrate immunohistochemically with LHRH antiserum without colchicine treatment, we used a transgenic rat in which LHRH tagged with enhanced green fluorescence protein facilitated the precise detection of LHRH-producing neuronal cell bodies and processes. This is the first study to report on synaptic inputs to LHRH-containing neurons at the ultrastructural level using this transgenic model. We also used immunohistochemistry to investigate the neuronal interaction between GALP- and LHRH-containing neurons. The experiments revealed that GALP-containing nerve terminals lie in close apposition with LHRH-containing cell bodies and processes in the medial preoptic area and the bed nucleus of the stria terminalis. At the ultrastructural level, the GALP-positive nerve terminals were found to make axo-somatic and axo-dendritic synaptic contacts with the EGFP-positive neurons in these areas. These results strongly suggest that GALP-containing neurons provide direct input to LHRH-containing neurons and that GALP plays a crucial role in the regulation of LH secretion via LHRH.
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Affiliation(s)
- Fumiko Takenoya
- Department of Anatomy I, Showa University School of Medicine, Tokyo 142-8555, Japan
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39
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Zeng H, Gragerov A, Hohmann JG, Pavlova MN, Schimpf BA, Xu H, Wu LJ, Toyoda H, Zhao MG, Rohde AD, Gragerova G, Onrust R, Bergmann JE, Zhuo M, Gaitanaris GA. Neuromedin U receptor 2-deficient mice display differential responses in sensory perception, stress, and feeding. Mol Cell Biol 2006; 26:9352-63. [PMID: 17030627 PMCID: PMC1698522 DOI: 10.1128/mcb.01148-06] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neuromedin U (NMU) is a highly conserved neuropeptide with a variety of physiological functions mediated by two receptors, peripheral NMUR1 and central nervous system NMUR2. Here we report the generation and phenotypic characterization of mice deficient in the central nervous system receptor NMUR2. We show that behavioral effects, such as suppression of food intake, enhanced pain response, and excessive grooming induced by intracerebroventricular NMU administration were abolished in the NMUR2 knockout (KO) mice, establishing a causal role for NMUR2 in mediating NMU's central effects on these behaviors. In contrast to the NMU peptide-deficient mice, NMUR2 KO mice appeared normal with regard to stress, anxiety, body weight regulation, and food consumption. However, the NMUR2 KO mice showed reduced pain sensitivity in both the hot plate and formalin tests. Furthermore, facilitated excitatory synaptic transmission in spinal dorsal horn neurons, a mechanism by which NMU stimulates pain, did not occur in NMUR2 KO mice. These results provide significant insights into a functional dissection of the differential contribution of peripherally or centrally acting NMU system. They suggest that NMUR2 plays a more significant role in central pain processing than other brain functions including stress/anxiety and regulation of feeding.
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Kuramochi M, Onaka T, Kohno D, Kato S, Yada T. Galanin-like peptide stimulates food intake via activation of neuropeptide Y neurons in the hypothalamic dorsomedial nucleus of the rat. Endocrinology 2006; 147:1744-52. [PMID: 16410310 DOI: 10.1210/en.2005-0907] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Galanin-like peptide (GALP), a 29-amino-acid neuropeptide, is located in the hypothalamic arcuate nucleus (ARC), binds to galanin receptor subtype 2, and induces food intake upon intracerebroventricular (icv) injection in rats. However, neural mechanisms underlying its orexigenic action remain unclear. We aimed to identify the nuclei and neuron species that mediate the food intake in response to icv GALP injection. Intracerebroventricular injection of GALP, as powerfully as that of neuropeptide Y (NYP), increased food intake for the initial 2 h. GALP injected focally into the dorsomedial nucleus (DMN), but not the ARC, lateral hypothalamus, or paraventricular nucleus (PVN), stimulated food intake for 2 h after injection. In contrast, galanin injected into the DMN had no effect. DMN-lesion rats that received icv GALP injection showed attenuated feeding compared with control rats. Intracerebroventricular GALP injection increased c-Fos expression in NPY-containing neurons in the DMN, but not the ARC. GALP increased the cytosolic calcium concentration ([Ca(2+)](i)) in NPY-immunoreactive neurons isolated from the DMN, but not the ARC. Furthermore, both anti-NPY IgG and NPY antagonists, when preinjected, counteracted the feeding induced by GALP injection. These data show that icv GALP injection induces a potent short-term stimulation of food intake mainly via activation of NPY-containing neurons in the DMN.
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Affiliation(s)
- Motoki Kuramochi
- Department of Physiology, Division of Integrative Physiology, Jichi Medical School, Minamikawachi, Kawachi, Tochigi, Japan
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Kageyama H, Kita T, Toshinai K, Guan JL, Date Y, Takenoya F, Kato S, Matsumoto H, Ohtaki T, Nakazato M, Shioda S. Galanin-like peptide promotes feeding behaviour via activation of orexinergic neurones in the rat lateral hypothalamus. J Neuroendocrinol 2006; 18:33-41. [PMID: 16451218 DOI: 10.1111/j.1365-2826.2005.01382.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Galanin-like peptide (GALP) is produced in neurones in the hypothalamic arcuate nucleus and is implicated in the neural control of feeding behaviour. Previously, we have reported that GALP immunoreactive fibres were in direct contact with orexin/hypocretin immunoreactive neurones in the rat lateral hypothalamus using double-immunofluorescence. Centrally administered GALP is known to stimulate feeding behaviour. However, the target neurones of this action have not been clarified. The present study aimed to determine features of the GALP-mediated neuronal feeding pathway in rat. Accordingly, at the ultrastructural level, GALP-immunoreactive axon terminals were found to make synapses on orexin/hypocretin immunoreactive cell bodies and dendritic processes in the lateral hypothalamus. c-Fos immunoreactivity was expressed in orexin/hypocretin-immunoreactive neurones but not in melanin concentrating hormone-immunoreactive neurones in the lateral hypothalamus at 90 min after the application of GALP by i.c.v. infusion. Furthermore, to determine whether GALP regulates feeding behaviour via orexin/hypocretin neurones, the feeding behaviour of rats was studied following GALP i.c.v. injection with or without anti-orexin A and B immunoglobulin (IgG) pretreatment. The anti-orexin IgGs markedly inhibited GALP-induced hyperphagia. These results suggest that orexin/hypocretin-containing neurones in the lateral hypothalamus are targeted by GALP, and that GALP-induced hyperphagia is mediated via orexin/hypocretin neurones in the rat hypothalamus.
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Affiliation(s)
- H Kageyama
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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Stoyanovitch AG, Johnson MA, Clifton DK, Steiner RA, Fraley GS. Galanin-like peptide rescues reproductive function in the diabetic rat. Diabetes 2005; 54:2471-6. [PMID: 16046316 DOI: 10.2337/diabetes.54.8.2471] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Galanin-like peptide (GALP) is expressed in the hypothalamic arcuate nucleus and is regulated by leptin and insulin. Centrally administered GALP stimulates gonadotropin secretion and sexual behavior in the rat. Type 1 diabetes is associated with reduced expression of GALP, as well as an overall decline in reproductive function. We postulated that tonic activity of GALP in the brain is required to sustain normal reproductive activity. To test this hypothesis, we examined whether central (intracerebroventricular) immunoblockade of GALP would reduce sexual behaviors and serum levels of luteinizing hormone (LH) in normal adult male rats. We found that GALP antibody reversibly reduced serum levels of LH and abolished male sexual behaviors (P < 0.05 and 0.001, respectively). Second, we tested whether intracerebroventricular GALP could restore normal plasma LH levels and sexual behavior in diabetic animals. We compared groups of diabetic rats that received intracerebroventricular GALP or vehicle and found that GALP increased serum levels of LH and sexual behavior. Third, we examined whether intracerebroventricular administration of affinity-purified GALP antibody could block the effect of insulin and leptin in reversing the effects of diabetes on LH and sexual behavior. We found that treatment of diabetic animals with insulin and leptin nearly normalized LH levels and sexual behaviors; however, this effect was attenuated by intracerebroventricular administration of GALP antibody (P < 0.05). These observations demonstrate that endogenous GALP provides trophic support to the neuroendocrine reproductive axis, including sexual behavior.
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Affiliation(s)
- Angela G Stoyanovitch
- Biology Department, 35 E. 12th St., PSC 3065, Box 9000, Biology Dept., Hope College, Holland, MI 49423, USA
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Kauffman AS, Buenzle J, Fraley GS, Rissman EF. Effects of galanin-like peptide (GALP) on locomotion, reproduction, and body weight in female and male mice. Horm Behav 2005; 48:141-51. [PMID: 16042964 DOI: 10.1016/j.yhbeh.2005.01.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 01/30/2005] [Accepted: 01/31/2005] [Indexed: 11/17/2022]
Abstract
Galanin-like peptide (GALP) has been implicated in the neuroendocrine regulation of both feeding and reproduction. In male rodents and primates, intracerebroventricular (icv) infusions of GALP stimulate luteinizing hormone (LH) release, induce Fos expression in brain areas implicated in feeding and reproduction, and affect food intake and body weight in rodents. In gonad-intact and castrated male rats, icv administration of GALP also stimulates male sexual behavior. While the effects of GALP on male physiology and behavior are well documented, no studies have addressed such a role of GALP in females. We tested the effects of icv GALP infusions on LH release, locomotor activity, motor control, and body weight regulation in adult ovariectomized female mice hormonally primed with estradiol benzoate and progesterone. In addition, sexually-experienced male and female mice were treated with GALP and tested for sexual behavior. In females, GALP reduced open-field locomotor activity, the ability to maintain grip on an accelerating rotarod, and 24-h body weight in a dose-dependent manner. GALP also increased LH secretion in female mice, an effect that was blocked by pre-treatment with Antide, a gonadotropin-releasing hormone (GnRH) type-1 receptor antagonist. GALP infusions slightly decreased the occurrence of lordosis behavior in female mice and significantly increased the latencies with which females displayed receptivity. Unlike previous reports in male rats, GALP inhibited male sexual behavior in mice. Our data indicate that in female mice, GALP stimulates LH release via GnRH, and decreases body weight, motor control, and locomotor activity via GnRH-independent pathways. Furthermore, our sexual behavior and locomotor findings suggest species-specific differences in the mechanism and/or location of GALP action in the brains of rats and mice.
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Affiliation(s)
- Alexander S Kauffman
- Department of Biochemistry and Molecular Genetics, University of Virginia, 1229 Jordan Hall, 1300 Jefferson Park Avenue, Charlottesville, VA 22908, USA.
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Gottsch ML, Zeng H, Hohmann JG, Weinshenker D, Clifton DK, Steiner RA. Phenotypic analysis of mice deficient in the type 2 galanin receptor (GALR2). Mol Cell Biol 2005; 25:4804-11. [PMID: 15899880 PMCID: PMC1140643 DOI: 10.1128/mcb.25.11.4804-4811.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Galanin is a neuropeptide implicated in the regulation of feeding, reproduction, cognition, nociception, and seizure susceptibility. There are three known galanin receptor (GALR) subtypes (GALR1, GALR2, and GALR3), which bind to galanin with different affinities and have their own unique distributions, signaling mechanisms, and putative functions in the brain and peripheral nervous system. To gain further insight into the possible physiological significance of GALR2, we created mutant mice that were deficient in GALR2 and compared their phenotype to that of wild-type (WT) littermate or age-matched controls, with respect to basic motor and sensory function, feeding behavior, reproduction, mood, learning and memory, and seizure susceptibility. Phenotypic analysis revealed that animals bearing a deletion of GALR2 did not differ significantly from their WT controls in any of the measured variables. We conclude that either GALR2 plays no role in these physiological functions or through redundancy or compensation these mutant animals can adapt to the congenital absence of GALR2. It is also conceivable that GALR2 plays only a subtle role in some of these functions and that the impact of its loss could not be detected by the analytical procedures used here.
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Affiliation(s)
- Michelle L Gottsch
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
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Lang R, Berger A, Santic R, Geisberger R, Hermann A, Herzog H, Kofler B. Pharmacological and functional characterization of galanin-like peptide fragments as potent galanin receptor agonists. Neuropeptides 2005; 39:179-84. [PMID: 15944009 DOI: 10.1016/j.npep.2004.12.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022]
Abstract
The hypothalamic galanin-like peptide (GALP) was isolated by its ability to activate galanin receptors. The mature porcine GALP is a 60-amino acid neuropeptide proteolytically processed from a 120-amino acid precursor protein. It contains a region identical to the N-terminal 13-amino acids of the neuropeptide galanin. Within the sequence of human GALP (1-60) a potential proteolytic cleavage site between two basic amino acids is present at position 33, which might lead to a shorter C-terminally amidated peptide. In addition, the first two amino acids could be potentially removed via the action of dipeptidase IV. Ligand binding assays using the human neuroblastoma cell line SH-SY5Y transfected with the respective galanin receptors revealed that human GALP (1-60) displayed the highest affinity for the galanin receptor subtype GalR3 (IC50 = 10 nM) followed by GalR2 (IC50 = 28 nM) and GalR1 (IC50 = 77 nM). Ligand binding assays and functional studies showed that the human GALP (3-32) fragment was at least as potent as full length GALP (1-60). Other studies have shown that shorter fragments like human GALP (1-21) and GALP (22-60) were not effective on feeding responses in mice as compared to the full length peptide. Taken together these data suggest that the putative fragment GALP (3-32) might represent the strongest mediator of biological GALP activity. Furthermore it might be a useful tool to study the affinity of GALP to galanin receptors and to search for specific GALP receptors.
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Affiliation(s)
- Roland Lang
- Department of Pediatrics, Paracelsus Private Medical University Salzburg, Muellner-Hauptstrasse 48, 5020 Salzburg, Austria
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Hökfelt T. Galanin and its receptors: introduction to the Third International Symposium, San Diego, California, USA, 21-22 October 2004. Neuropeptides 2005; 39:125-42. [PMID: 15908000 DOI: 10.1016/j.npep.2005.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Third Galanin Symposium presented many different and exciting results on galanin research reflecting a major progress since the previous symposium in 1998. A major impression was the many possible relationships of galaninergic mechanisms to important brain functions such as development, cognition and ageing as well as many aspects related to a wide spectrum of diseases, including Alzheimer's disease, anxiety/depression, addiction, obesity, pain and tumour growth. These studies were based on an extensive armament of methodologies including various strains of transgenic mice. Unfortunately, the pharmaceutical industry had only a minor participation. Nevertheless, exciting developments in the generation of agonists and antagonists are emerging, providing hope that we at the next symposium will be able to validitate many of the challenging hypotheses concerning galanin and disease with the help of pharmacological tools.
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Affiliation(s)
- Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, S-171 77 Stockholm, Sweden.
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