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Neuropeptidergic Control of Feeding: Focus on the Galanin Family of Peptides. Int J Mol Sci 2021; 22:ijms22052544. [PMID: 33802616 PMCID: PMC7961366 DOI: 10.3390/ijms22052544] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/24/2021] [Accepted: 02/27/2021] [Indexed: 12/16/2022] Open
Abstract
Obesity/overweight are important health problems due to metabolic complications. Dysregulation of peptides exerting orexigenic/anorexigenic effects must be investigated in-depth to understand the mechanisms involved in feeding behaviour. One of the most important and studied orexigenic peptides is galanin (GAL). The aim of this review is to update the mechanisms of action and physiological roles played by the GAL family of peptides (GAL, GAL-like peptide, GAL message-associated peptide, alarin) in the control of food intake and to review the involvement of these peptides in metabolic diseases and food intake disorders in experimental animal models and humans. The interaction between GAL and NPY in feeding and energy metabolism, the relationships between GAL and other substances involved in food intake mechanisms, the potential pharmacological strategies to treat food intake disorders and obesity and the possible clinical applications will be mentioned and discussed. Some research lines are suggested to be developed in the future, such as studies focused on GAL receptor/neuropeptide Y Y1 receptor interactions in hypothalamic and extra-hypothalamic nuclei and sexual differences regarding the expression of GAL in feeding behaviour. It is also important to study the possible GAL resistance in obese individuals to better understand the molecular mechanisms by which GAL regulates insulin/glucose metabolism. GAL does not exert a pivotal role in weight regulation and food intake, but this role is crucial in fat intake and also exerts an important action by regulating the activity of other key compounds under conditions of stress/altered diet.
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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Lee YN, Reyes-Alcaraz A, Yun S, Lee CS, Hwang JI, Seong JY. Exploring the molecular structures that confer ligand selectivity for galanin type II and III receptors. PLoS One 2020; 15:e0230872. [PMID: 32231393 PMCID: PMC7108740 DOI: 10.1371/journal.pone.0230872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/10/2020] [Indexed: 01/09/2023] Open
Abstract
Galanin receptors (GALRs) belong to the superfamily of G-protein coupled receptors. The three GALR subtypes (GALR1, GALR2, and GALR3) are activated by their endogenous ligands: spexin (SPX) and galanin (GAL). The synthetic SPX-based GALR2-specific agonist, SG2A, plays a dual role in the regulation of appetite and depression-like behaviors. Little is known, however, about the molecular interaction between GALR2 and SG2A. Using site-directed mutagenesis and domain swapping between GALR2 and GALR3, we identified residues in GALR2 that promote interaction with SG2A and residues in GALR3 that inhibit interaction with SG2A. In particular, Phe103, Phe106, and His110 in the transmembrane helix 3 (TM3) domain; Val193, Phe194, and Ser195 in the TM5 domain; and Leu273 in the extracellular loop 3 (ECL3) domain of GALR2 provide favorable interactions with the Asn5, Ala7, Phe11, and Pro13 residues of SG2A. Our results explain how SG2A achieves selective interaction with GALR2 and inhibits interaction with GALR3. The results described here can be used broadly for in silico virtual screening of small molecules for the development of GALR subtype-specific agonists and/or antagonists.
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MESH Headings
- Amino Acid Sequence
- Animals
- HEK293 Cells
- Humans
- Ligands
- Mice
- Mutation
- Protein Domains
- Receptor, Galanin, Type 2/chemistry
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/chemistry
- Receptor, Galanin, Type 3/genetics
- Receptor, Galanin, Type 3/metabolism
- Substrate Specificity
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Affiliation(s)
- Yoo-Na Lee
- The GPCR laboratory, Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
| | - Arfaxad Reyes-Alcaraz
- The GPCR laboratory, Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
- College of Pharmacy, University of Houston, Houston, Texas, United States of America
| | - Seongsik Yun
- The GPCR laboratory, Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
| | - Cheol Soon Lee
- Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jong-Ik Hwang
- The GPCR laboratory, Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jae Young Seong
- The GPCR laboratory, Graduate School of Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea
- * E-mail:
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Leidmaa E, Gazea M, Patchev AV, Pissioti A, Christian Gassen N, Kimura M, Liposits Z, Kallo I, Almeida OFX. Blunted leptin sensitivity during hedonic overeating can be reinstated by activating galanin 2 receptors (Gal2R) in the lateral hypothalamus. Acta Physiol (Oxf) 2020; 228:e13345. [PMID: 31310704 DOI: 10.1111/apha.13345] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
AIM Since foods with high hedonic value are often consumed in excess of energetic needs, this study was designed to identify the mechanisms that may counter anorexigenic signalling in the presence of hedonic foods in lean animals. METHODS Mice, in different states of satiety (fed/fasted, or fed/fasted and treated with ghrelin or leptin, respectively), were allowed to choose between high-fat/high-sucrose and standard foods. Intake of each food type and the activity of hypothalamic neuropetidergic neurons that regulate appetite were monitored. In some cases, food choice was monitored in leptin-injected fasted mice that received microinjections of galanin receptor agonists into the lateral hypothalamus. RESULTS Appetite-stimulating orexin neurons in the lateral hypothalamus are rapidly activated when lean, satiated mice consume a highly palatable food (PF); such activation (upregulated c-Fos expression) occurred even after administration of the anorexigenic hormone leptin and despite intact leptin signalling in the hypothalamus. The ability of leptin to restrain PF eating is restored when a galanin receptor 2 (Gal2R) agonist is injected into the lateral hypothalamus. CONCLUSION Hedonically-loaded foods interrupt the inhibitory actions of leptin on orexin neurons and interfere with the homeostatic control of feeding. Overeating of palatable foods can be curtailed in lean animals by activating Gal2R in the lateral hypothalamus.
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Affiliation(s)
- Este Leidmaa
- Max Planck Institute of Psychiatry Munich Germany
- Graduate School of Systems Neuroscience Munich University Planegg‐Martinsried Germany
- Institute of Molecular Psychiatry Bonn Germany
| | - Mary Gazea
- Max Planck Institute of Psychiatry Munich Germany
| | | | | | | | | | - Zsolt Liposits
- Institute of Experimental Medicine Hungarian Academy of Sciences Budapest Hungary
| | - Imre Kallo
- Institute of Experimental Medicine Hungarian Academy of Sciences Budapest Hungary
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Conformational signatures in β-arrestin2 reveal natural biased agonism at a G-protein-coupled receptor. Commun Biol 2018; 1:128. [PMID: 30272007 PMCID: PMC6123711 DOI: 10.1038/s42003-018-0134-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 08/08/2018] [Indexed: 01/14/2023] Open
Abstract
Discovery of biased ligands and receptor mutants allows characterization of G-protein- and β-arrestin-mediated signaling mechanisms of G-protein-coupled receptors (GPCRs). However, the structural mechanisms underlying biased agonism remain unclear for many GPCRs. We show that while Galanin induces the activation of the galanin receptor 2 (Galr2) that leads to a robust stimulation toward Gαq-protein and β-arrestin1/2, an alternative ligand Spexin and its analog have biased agonism toward G-protein signaling relative to Galanin. We used intramolecular fluorescein arsenical hairpin bioluminescence resonance energy transfer-based biosensors of β-arrestin2 combined with NanoBit technology to measure β-arrestin2–Galr2 interactions in real-time living systems. We found that Spexin and Galanin induce specific active conformations of Galr2, which may lead to different internalization rates of the receptor as well as different signaling outputs. This work represents an additional pharmacological evidence of endogenous G-protein-biased agonism at a GPCR. Arfaxad Reyes-Alcaraz et al. report that galanin induces robust signaling mediated by β-arrestin1/2 and Gαq, whereas an alternative ligand spexin prefers the Gαq-protein signaling pathway. This study provides mechanistic insights into how endogenous ligands can generate biased signaling outputs.
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Song J, Kim OY. Galanin's implications for post-stroke improvement. Anat Cell Biol 2016; 49:223-230. [PMID: 28127496 PMCID: PMC5266107 DOI: 10.5115/acb.2016.49.4.223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/16/2016] [Accepted: 12/08/2016] [Indexed: 02/07/2023] Open
Abstract
Stroke leads to a variety of pathophysiological conditions such as ischemic infarct, cerebral inflammation, neuronal damage, cognitive decline, and depression. Many endeavors have been tried to find the therapeutic solutions to attenuate severe neuropathogenesis after stroke. Several studies have reported that a decrease in the neuropeptide regulator ‘galanin’ is associated with neuronal loss, learning and memory dysfunctions, and depression following a stroke. The present review summarized recent evidences on the function and the therapeutic potential of galanin in post-ischemic stroke to provide a further understanding of galanin's role. Hence, we suggest that galanin needs to be considered as a therapeutic factor in the alleviation of post-stroke pathologies.
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Affiliation(s)
- Juhyun Song
- Department of Biomedical Sciences, Center for Creative Biomedical Scientists at Chonnam National University, Gwangju, Korea.; Human Life Research Center, Dong-A University, Busan, Korea
| | - Oh Yoen Kim
- Human Life Research Center, Dong-A University, Busan, Korea.; Department of Food Science and Nutrition, Dong-A University, Brain Busan 21, Busan, Korea
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Bu L, Chang X, Cheng X, Yao Q, Su B, Sheng C, Qu S. Activated central galanin type 1 receptor alleviated insulin resistance in diabetic rat muscle. J Neurosci Res 2016; 94:947-55. [PMID: 27410235 DOI: 10.1002/jnr.23775] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 01/14/2023]
Affiliation(s)
- Le Bu
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Xusheng Chang
- Department of General Surgery; Yancheng City First People's Hospital; Yancheng City Jiangsu People's Republic of China
| | - Xiaoyun Cheng
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Qian Yao
- Key Laboratory of Sichuan Province of Medicinal Chemistry; Chengdu University; Chengdu People's Republic of China
| | - Bin Su
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Chunjun Sheng
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Shen Qu
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
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Soares FRC, Silote GP, Almeida-Santos AF, Aguiar DC, Schenberg LC, Beijamini V. Galanin microinjection into the dorsal periaqueductal gray matter produces paradigm-dependent anxiolytic effects. Brain Res Bull 2016; 121:42-7. [PMID: 26751815 DOI: 10.1016/j.brainresbull.2015.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/09/2015] [Accepted: 12/28/2015] [Indexed: 01/07/2023]
Abstract
Galanin is a peptide that is present in the central nervous system in mammals, including rodents and humans. The actions of galanin are mediated by three types of metabotropic receptors: GAL1, GAL2, and GAL3. GAL1 and GAL3 increase K(+) efflux, and GAL2 increases intracellular Ca(2+) levels. The distribution of galanin and its receptors suggests its involvement in fear and/or anxiety. The periaqueductal gray matter (PAG) is a key mediator of defensive behaviors that is both targeted by galaninergic projections and supplied with GAL1 receptors and, less markedly, GAL2 receptors. We examined the effects of galanin microinjections in the dorsal PAG (dPAG) on the performance of rats in different models of anxiety. Male Wistar rats (n=7-12) were implanted with guide cannulae in the dPAG. They received microinjections of either galanin (0.3, 1.0, and 3.0 nmol) or vehicle and were tested in the Vogel conflict test (VCT), elevated plus maze (EPM), and elevated T-maze (ETM). Rats that were tested in the ETM were further evaluated for exploratory activity in the open field test (OFT). Galanin microinjections had no effects on anxiety-like behavior in the EPM or VCT or exploratory activity in the EPM or OFT. In the ETM, however, microinjections of 3 nmol galanin impaired learned anxiety (i.e., avoidance of the open arms) without changing unconditioned fear (i.e., escape from the open arms). The present data suggest that galanin transmission in the dPAG inhibits the acquisition of anxiety-like responses in the ETM.
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Affiliation(s)
- F R C Soares
- Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES 29043-900, Brazil
| | - G P Silote
- Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES 29043-900, Brazil
| | - A F Almeida-Santos
- Department of Pharmacology, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - D C Aguiar
- Department of Pharmacology, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - L C Schenberg
- Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES 29043-900, Brazil
| | - V Beijamini
- Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES 29043-900, Brazil.
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Zhang Z, Fang P, He B, Guo L, Runesson J, Langel Ü, Shi M, Zhu Y, Bo P. Central Administration of Galanin Receptor 1 Agonist Boosted Insulin Sensitivity in Adipose Cells of Diabetic Rats. J Diabetes Res 2016; 2016:9095648. [PMID: 27127795 PMCID: PMC4835658 DOI: 10.1155/2016/9095648] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 01/18/2023] Open
Abstract
Our previous studies testified the beneficial effect of central galanin on insulin sensitivity of type 2 diabetic rats. The aim of the study was further to investigate whether central M617, a galanin receptor 1 agonist, can benefit insulin sensitivity. The effects of intracerebroventricular administration of M617 on insulin sensitivity and insulin signaling were evaluated in adipose tissues of type 2 diabetic rats. The results showed that central injection of M617 significantly increased plasma adiponectin contents, glucose infusion rates in hyperinsulinemic-euglycemic clamp tests, GLUT4 mRNA expression levels, GLUT4 contents in plasma membranes, and total cell membranes of the adipose cells but reduced the plasma C-reactive protein concentration in nondiabetic and diabetic rats. The ratios of GLUT4 contents were higher in plasma membranes to total cell membranes in both nondiabetic and diabetic M617 groups than each control. In addition, the central administration of M617 enhanced the ratios of pAkt/Akt and pAS160/AS160, but not phosphorylative cAMP response element-binding protein (pCREB)/CREB in the adipose cells of nondiabetic and diabetic rats. These results suggest that excitation of central galanin receptor 1 facilitates insulin sensitivity via activation of the Akt/AS160 signaling pathway in the fat cells of type 2 diabetic rats.
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MESH Headings
- Adipocytes/drug effects
- Adipocytes/metabolism
- Adiponectin/blood
- Animals
- Biomarkers/blood
- Bradykinin/administration & dosage
- Bradykinin/analogs & derivatives
- C-Reactive Protein/analysis
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/genetics
- Disease Models, Animal
- GTPase-Activating Proteins/metabolism
- Galanin/administration & dosage
- Glucose Transporter Type 4/genetics
- Glucose Transporter Type 4/metabolism
- Hypoglycemic Agents/pharmacology
- Injections, Intraventricular
- Insulin/pharmacology
- Insulin Resistance
- Male
- Peptide Fragments/administration & dosage
- Phosphorylation
- Proto-Oncogene Proteins c-akt/metabolism
- Rats, Wistar
- Receptor, Galanin, Type 1/agonists
- Receptor, Galanin, Type 1/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Penghua Fang
- Department of Physiology, School of Hanlin, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, China
- Key Laboratory of Gerontology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Biao He
- Key Laboratory of Gerontology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Lili Guo
- Key Laboratory of Gerontology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Johan Runesson
- Department of Neurochemistry, Arrhenius Laboratories for Natural Sciences Stockholm University, 10691 Stockholm, Sweden
| | - Ülo Langel
- Department of Neurochemistry, Arrhenius Laboratories for Natural Sciences Stockholm University, 10691 Stockholm, Sweden
| | - Mingyi Shi
- Key Laboratory of Gerontology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
- *Yan Zhu: and
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
- Key Laboratory of Gerontology, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
- *Ping Bo:
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Type 2 diabetes mellitus as a disorder of galanin resistance. Exp Gerontol 2015; 73:72-7. [PMID: 26585047 DOI: 10.1016/j.exger.2015.11.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 11/10/2015] [Accepted: 11/12/2015] [Indexed: 12/16/2022]
Abstract
The increasing prevalence of type 2 diabetes mellitus with its high morbidity and mortality becomes an important health problem. The multifactorial etiology of type 2 diabetes mellitus is relative to many gene and molecule alterations, and increased insulin resistance. Besides these, however, there are still other predisposing and risk factors accounting for type 2 diabetes mellitus not to be identified and recognized. Emerging evidence indicated that defects in galanin function played a crucial role in development of type 2 diabetes mellitus. Galanin homeostasis is tightly relative to insulin resistance and is regulated by blood glucose. Hyperglycemia, hyperinsulinism, enhanced plasma galanin levels and decreased galanin receptor activities are some of the characters of type 2 diabetes mellitus. The discrepancy between high insulin level and low glucose handling is named as insulin resistance. Similarly, the discrepancy between high galanin level and low glucose handling may be denominated as galanin resistance too. In this review, the characteristic milestones of type 2 diabetes mellitus were condensed as two analogical conceptual models, obesity-hyper-insulin-insulin resistance-type 2 diabetes mellitus and obesity-hyper-galanin-galanin resistance-type 2 diabetes mellitus. Both galanin resistance and insulin resistance are correlative with each other. Conceptualizing the etiology of type 2 diabetes mellitus as a disorder of galanin resistance may inspire a new concept to deepen our knowledge about pathogenesis of type 2 diabetes mellitus, eventually leading to novel preventive and therapeutic interventions for type 2 diabetes mellitus.
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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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Freimann K, Kurrikoff K, Langel Ü. Galanin receptors as a potential target for neurological disease. Expert Opin Ther Targets 2015. [PMID: 26220265 DOI: 10.1517/14728222.2015.1072513] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Galanin is a 29/30 amino acid long neuropeptide that is widely expressed in the brains of many mammals. Galanin exerts its biological activities through three different G protein-coupled receptors, GalR1, GalR2 and GalR3. The widespread distribution of galanin and its receptors in the CNS and the various physiological and pharmacological effects of galanin make the galanin receptors attractive drug targets. AREAS COVERED This review provides an overview of the role of galanin and its receptors in the CNS, the involvement of the galaninergic system in various neurological diseases and the development of new galanin receptor-specific ligands. EXPERT OPINION Recent advances and novel approaches in migrating the directions of subtype-selective ligand development and chemical modifications of the peptide backbone highlight the importance of the galanin neurochemical system as a potential target for drug development.
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Affiliation(s)
- Krista Freimann
- a 1 University of Tartu, Institute of Technology , Tartu, Estonia +372 737 4871 ;
| | - Kaido Kurrikoff
- b 2 University of Tartu, Institute of Technology , Tartu, Estonia
| | - Ülo Langel
- c 3 University of Tartu, Institute of Technology , Tartu, Estonia.,d 4 Stockholm University, Arrhenius Laboratories for Natural Science, Department of Neurochemistry , Stockholm, Sweden
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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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Amorim D, David-Pereira A, Marques P, Puga S, Rebelo P, Costa P, Pertovaara A, Almeida A, Pinto-Ribeiro F. A role of supraspinal galanin in behavioural hyperalgesia in the rat. PLoS One 2014; 9:e113077. [PMID: 25405608 PMCID: PMC4236133 DOI: 10.1371/journal.pone.0113077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 10/13/2014] [Indexed: 02/08/2023] Open
Abstract
INTRODUCTION In chronic pain disorders, galanin (GAL) is able to either facilitate or inhibit nociception in the spinal cord but the contribution of supraspinal galanin to pain signalling is mostly unknown. The dorsomedial nucleus of the hypothalamus (DMH) is rich in galanin receptors (GALR) and is involved in behavioural hyperalgesia. In this study, we evaluated the contribution of supraspinal GAL to behavioural hyperalgesia in experimental monoarthritis. METHODS In Wistar-Han males with a four week kaolin/carrageenan-induced monoarthritis (ARTH), paw-withdrawal latency (PWL) was assessed before and after DMH administration of exogenous GAL, a non-specific GALR antagonist (M40), a specific GALR1 agonist (M617) and a specific GALR2 antagonist (M871). Additionally, the analysis of c-Fos expression after GAL injection in the DMH was used to investigate the potential involvement of brainstem pain control centres. Finally, electrophysiological recordings were performed to evaluate whether pronociceptive On- or antinociceptive Off-like cells in the rostral ventromedial medulla (RVM) relay the effect of GAL. RESULTS Exogenous GAL in the DMH decreased PWL in ARTH and SHAM animals, an effect that was mimicked by a GALR1 agonist (M617). In SHAM animals, an unselective GALR antagonist (M40) increased PWL, while a GALR2 antagonist (M871) decreased PWL. M40 or M871 failed to influence PWL in ARTH animals. Exogenous GAL increased c-Fos expression in the RVM and dorsal raphe nucleus (DRN), with effects being more prominent in SHAM than ARTH animals. Exogenous GAL failed to influence activity of RVM On- or Off-like cells of SHAM and ARTH animals. CONCLUSIONS Overall, exogenous GAL in the DMH had a pronociceptive effect that is mediated by GALR1 in healthy and arthritic animals and is associated with alterations of c-Fos expression in RVM and DRN that are serotonergic brainstem nuclei known to be involved in the regulation of pain.
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Affiliation(s)
- Diana Amorim
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Ana David-Pereira
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Rebelo
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrício Costa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Antti Pertovaara
- Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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15
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Su ZI, Wenzel J, Ettenberg A, Ben-Shahar O. Prior extended daily access to cocaine elevates the reward threshold in a conditioned place preference test. Addict Biol 2014; 19:826-37. [PMID: 23634951 DOI: 10.1111/adb.12053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have previously shown that extended-access subjects exhibit heightened motivation for cocaine in the runway model, as reflected by reduced number of retreats. This heightened motivation could reflect either an increase in cocaine-induced reward or a decrease in cocaine-induced aversion. The current experiment was therefore devised to assess the cocaine-induced reward and aversion in extended-access rats using a place conditioning test. Rats trained to lever press for intravenous (IV) cocaine (0.25 mg/infusion) were provided 6-hour daily access to the drug over 10 days. Lever pressing in control subjects produced IV infusions of saline. Following drug self-administration, subjects underwent place conditioning for the immediate or delayed effects of cocaine (1.0 or 2.5 mg/kg, IV). In control subjects, the immediate effects of the low dose of cocaine produced conditioned places preferences (CPPs), while the delayed effects produced conditioned place aversions (CPAs). In contrast, the animals receiving low cocaine dose for 6 hours, exhibited place aversions but not preferences; an effect that was reversed when the dose of cocaine was increased. Additionally, in the 6-hour group, delayed conditioning was associated with a reduction in zif268 immunoreactivity in the medial prefrontal cortex and nucleus accumbens shell while immediate conditioning was associated with an increase in zif268-positive cells in the central nucleus of the amygdala. Collectively, these data suggest that extended daily access to cocaine produces a shift in the subject's perceived reward threshold that is paralleled by alterations in the activity of both the reward and stress pathways.
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Affiliation(s)
- Zu-In Su
- Behavioral Pharmacology Laboratory; Department of Psychological and Brain Sciences; University of California; Santa Barbara CA USA
| | - Jennifer Wenzel
- Behavioral Pharmacology Laboratory; Department of Psychological and Brain Sciences; University of California; Santa Barbara CA USA
| | - Aaron Ettenberg
- Behavioral Pharmacology Laboratory; Department of Psychological and Brain Sciences; University of California; Santa Barbara CA USA
| | - Osnat Ben-Shahar
- Behavioral Pharmacology Laboratory; Department of Psychological and Brain Sciences; University of California; Santa Barbara CA USA
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16
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Galanin receptor 2-neuropeptide Y Y1 receptor interactions in the amygdala lead to increased anxiolytic actions. Brain Struct Funct 2014; 220:2289-301. [DOI: 10.1007/s00429-014-0788-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/25/2014] [Indexed: 02/06/2023]
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17
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Yoshitake S, Kuteeva E, Hökfelt T, Mennicken F, Theodorsson E, Yamaguchi M, Kehr J, Yoshitake T. Correlation between the effects of local and intracerebroventricular infusions of galanin on 5-HT release studied by microdialysis, and distribution of galanin and galanin receptors in prefrontal cortex, ventral hippocampus, amygdala, hypothalamus, and st. Synapse 2014; 68:179-93. [DOI: 10.1002/syn.21730] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/26/2013] [Accepted: 12/20/2013] [Indexed: 01/30/2023]
Affiliation(s)
- Shimako Yoshitake
- Department of Physiology and Pharmacology; Karolinska Institutet; 171 77 Stockholm Sweden
| | - Eugenia Kuteeva
- Department of Neuroscience; Karolinska Institutet; 171 77 Stockholm Sweden
- Atlas Antibodies AB; AlbaNova University Center; SE-106 91 Stockholm Sweden
| | - Tomas Hökfelt
- Department of Neuroscience; Karolinska Institutet; 171 77 Stockholm Sweden
| | - Françoise Mennicken
- AstraZeneca R&D Montréal; 7171 Frederick-Banting-Ville St-Laurent Quebec H4S1Z9 Canada
| | - Elvar Theodorsson
- Divison of Clinical Chemistry; Linköping University, County Council of Östergötland; 581 85 Linköping Sweden
- Department of Clinical and Experimental Medicine; Faculty of Health Sciences, Linköping University, County Council of Östergötland; 581 85 Linköping Sweden
| | - Masatoshi Yamaguchi
- Faculty of Pharmaceutical Sciences; Fukuoka University; 8-19-1 Nanakuma, Johnan-ku Fukuoka 814-0180 Japan
| | - Jan Kehr
- Department of Physiology and Pharmacology; Karolinska Institutet; 171 77 Stockholm Sweden
- Pronexus Analytical AB; Grindstuvägen 44 167 33 Bromma Sweden
| | - Takashi Yoshitake
- Department of Physiology and Pharmacology; Karolinska Institutet; 171 77 Stockholm Sweden
- Graduate School of Medical and Dental Sciences; Kagoshima University; 8-35-1 Sakuragaoka Kagoshima 890-8544 Japan
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18
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Fang P, Shi M, Yu M, Guo L, Bo P, Zhang Z. Endogenous peptides as risk markers to assess the development of insulin resistance. Peptides 2014; 51:9-14. [PMID: 24184593 DOI: 10.1016/j.peptides.2013.10.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/19/2013] [Accepted: 10/21/2013] [Indexed: 01/15/2023]
Abstract
Insulin resistance, the reciprocal of insulin sensitivity, is known to be a characteristic of type 2 diabetes mellitus, and is regarded as an important mechanism in the pathogenesis. The hallmark of insulin resistance is a gradual break-down of insulin-regulative glucose uptake by muscle and adipose tissues in subjects. Insulin resistance is increasingly estimated in various disease conditions to examine and assess their etiology, pathogenesis and consequences. Although our understanding of insulin resistance has tremendously been improved in recent years, certain aspects of its estimation and etiology still remain elusive to clinicians and researchers. There are numerous factors involved in pathogenesis and mechanisms of insulin resistance. Recent studies have provided compelling clues about some peptides and proteins, including galanin, galanin-like peptide, ghrelin, adiponectin, retinol binding protein 4 (RBP4) and CRP, which may be used to simplify and to improve the determination of insulin resistance. And alterations of these peptide levels may be recognized as risk markers of developing insulin resistance and type 2 diabetes mellitus. This review examines the updated information for these peptides, highlighting the relations between these peptide levels and insulin resistance. The plasma high ghrelin, RBP4 and CRP as well as low galanin, GALP and adiponectin levels may be taken as the markers of deteriorating insulin resistance. An increase in the knowledge of these marker proteins and peptides will help us correctly diagnose and alleviate insulin resistance in clinic and study.
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Affiliation(s)
- Penghua Fang
- Research Institution of Combining Chinese Traditional and Western Medicine, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China; Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou, Jiangsu 225300, China
| | - Mingyi Shi
- Research Institution of Combining Chinese Traditional and Western Medicine, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Mei Yu
- Taizhou Hospital of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Taizhou, Jiangsu 225300, China
| | - Lili Guo
- Research Institution of Combining Chinese Traditional and Western Medicine, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Ping Bo
- Research Institution of Combining Chinese Traditional and Western Medicine, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China
| | - Zhenwen Zhang
- Research Institution of Combining Chinese Traditional and Western Medicine, Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China; Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu 225001, China.
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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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20
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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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21
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Central nervous system regulation of food intake and energy expenditure: role of galanin-mediated feeding behavior. Neurosci Bull 2012; 27:407-12. [PMID: 22108817 DOI: 10.1007/s12264-011-1841-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Galanin is a neuropeptide widely expressed in the brain. It is implicated in energy expenditure, feeding, and the regulation of body weight. Numerous studies have revealed that galanin regulates food intake via galanin receptors, 5-HT(1A) receptor and adrenergic α-2 receptor. In this review, we summarize recent findings that reveal the essential role of galanin in increasing food intake as well as body weight and that identify the individual galanin receptor subtypes involved in the brain's modulation of food intake and energy expenditure, to provide a theoretical basis for further studies of different aspects of galanin action.
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22
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Christiansen SH. Regulation of the galanin system in the brainstem and hypothalamus by electroconvulsive stimulation in mice. Neuropeptides 2011; 45:337-41. [PMID: 21820174 DOI: 10.1016/j.npep.2011.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 06/27/2011] [Accepted: 07/12/2011] [Indexed: 12/01/2022]
Abstract
Induction of seizures by electroconvulsive stimulation (ECS) is amongst the most efficacious treatments for major depression. However, the working mechanism by which ECS exerts its antidepressant effects remains elusive. The galanin system is regulated by ECS in seizure-prone brain regions and has been shown to modulate depression-like behaviour. To further explore its potential role in the antidepressant effects of ECS the galanin system was investigated by in situ hybridisation and [(125)I]-galanin receptor binding during repeated ECS in the locus coeruleus, dorsal raphe and discrete nuclei of the hypothalamus. Adult mice were treated with ECS once daily for 14 consecutive days, a paradigm previously shown to exert antidepressant-like effects. Significant increases in galanin transcription were found in the locus coeruleus and dorsomedial nuclei of the hypothalamus. In addition, GalR2 mRNA levels in the ventro- and dorsomedial nuclei of the hypothalamus were upregulated whereas no GalR1 mRNA upregulation was observed. [(125)I]-galanin receptor binding was downregulated in the ventromedial nuclei of the hypothalamus and dorsal raphe. These data show that the galanin system is regulated by repeated ECS in brain regions involved in monoaminergic neurotransmission and stress modulation thus indicating a possible role of the galanin system in the therapeutic effects of ECS.
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Affiliation(s)
- S H Christiansen
- Psychiatric Centre Copenhagen, Rigshospitalet O-6102, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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23
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Karakaş A, Coşkun H, Kaya A, Kücük A, Gündüz B. The effects of the intraamygdalar melatonin injections on the anxiety like behavior and the spatial memory performance in male Wistar rats. Behav Brain Res 2011; 222:141-50. [PMID: 21421010 DOI: 10.1016/j.bbr.2011.03.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 03/07/2011] [Accepted: 03/11/2011] [Indexed: 11/25/2022]
Abstract
In the present study, the effects of intraamygdalar administrations of melatonin (1 and 100μg/kg), saline and diazepam on the anxiety-like behavior and spatial memory performance in pinealectomized and sham-pinealectomized Wistar rats were investigated. The animals were tested by open field and elevated plus maze tests for anxiety-like behavior, and Morris water maze test for spatial memory. In open field, (a) diazepam was more effective in reducing the anxiety, (b) control subjects were more mobile than pinealectomized subjects and (c) 100μg/kg melatonin administrations reduced the velocity of the animals. In elevated plus maze, (a) 100μg/kg melatonin administrations increased the distance totally travelled and (b) enhanced the time spent in open arms, however, after the pinealectomy, 1μg/kg melatonin administrations decreased it and (c) control animals were less mobile than pinealectomized ones. In Morris water maze, (a) diazepam group travelled more distance than the others in control condition whereas, in pinealectomy condition high dose of melatonin and saline groups travelled more distance than the others, (b) in pinealectomy condition subjects who received 100μg/kg melatonin also travelled more distance than those who received 1μg/kg melatonin and diazepam, (c) the subjects who received 1μg/kg spent less time than those who received other treatments, and (d) in control condition subjects who received 100μg/kg melatonin were slower than those who received the other treatments. In conclusion, melatonin administration to amygdala decreased the anxiety; however, spatial memory performance of the rats was impaired by the pinealectomy and melatonin administrations.
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Affiliation(s)
- Alper Karakaş
- Department of Biology, Faculty of Arts and Sciences, Abant Izzet Baysal University, Bolu, Turkey. karakas
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Mitsukawa K, Lu X, Bartfai T. Galanin, galanin receptors, and drug targets. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:7-23. [PMID: 21299058 DOI: 10.1007/978-3-0346-0228-0_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Galanin, a neuropeptide widely expressed in the central and peripheral nervous systems and in the endocrine system, has been shown to regulate numerous physiological and pathological processes through interactions with three G-protein-coupled receptors, GalR1 through GalR3. Over the past decade, some of the receptor subtype-specific effects have been elucidated through pharmacological studies using subtype selective ligands, as well as through molecular approaches involving knockout animals. In this chapter, we summarize the current data which constitute the basis of targeting GalR1, GalR2, and GalR3 for the treatment of various human diseases and pathological conditions, including seizure, Alzheimer's disease, mood disorders, anxiety, alcohol intake in addiction, metabolic diseases, pain and solid tumors.
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Affiliation(s)
- K Mitsukawa
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Befort K, Filliol D, Ghate A, Darcq E, Matifas A, Muller J, Lardenois A, Thibault C, Dembele D, Le Merrer J, Becker JAJ, Poch O, Kieffer BL. Mu-opioid receptor activation induces transcriptional plasticity in the central extended amygdala. Eur J Neurosci 2008; 27:2973-84. [PMID: 18588537 DOI: 10.1111/j.1460-9568.2008.06273.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Addiction develops from the gradual adaptation of the brain to chronic drug exposure, and involves genetic reprogramming of neuronal function. The central extended amygdala (EAc) is a network formed by the central amygdala and the bed nucleus of the stria terminalis. This key site controls drug craving and seeking behaviors, and has not been investigated at the gene regulation level. We used Affymetrix microarrays to analyze transcriptional activity in the murine EAc, with a focus on mu-opioid receptor-associated events because these receptors mediate drug reward and dependence. We identified 132 genes whose expression is regulated by a chronic escalating morphine regimen in the EAc from wild-type but not mu-opioid receptor knockout mice. These modifications are mostly EAc-specific. Gene ontology analysis reveals an overrepresentation of neurogenesis, cell growth and signaling protein categories. A separate quantitative PCR analysis of genes in the last of these groups confirms the dysregulation of both orphan (Gpr88) and known (DrD1A, Adora2A, Cnr1, Grm5, Gpr6) G protein-coupled receptors, scaffolding (PSD95, Homer1) and signaling (Sgk, Cap1) proteins, and neuropeptides (CCK, galanin). These transcriptional modifications do not occur following a single morphine injection, and hence result from long-term adaptation to excessive mu receptor activation. Proteins encoded by these genes are classically associated with spine modules function in other brain areas, and therefore our data suggest a remodeling of EAc circuits at sites where glutamatergic and monoaminergic afferences interact. Together, mu receptor-dependent genes identified in this study potentially contribute to drug-induced neural plasticity, and provide a unique molecular repertoire towards understanding drug craving and relapse.
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Affiliation(s)
- K Befort
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Département Neurobiologie et Génétique, Illkirch, F-67400 France.
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Galanin: a potential role in mesolimbic dopamine-mediated instrumental behavior. Neurosci Biobehav Rev 2008; 32:1485-93. [PMID: 18632153 DOI: 10.1016/j.neubiorev.2008.05.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 05/20/2008] [Accepted: 05/27/2008] [Indexed: 11/21/2022]
Abstract
The involvement of the neuropeptide galanin in the consumption of the primary "commodities" of food and water is well established. However, the present review describes anatomical and behavioral evidence that suggests that galanin may also modulate ascending mesolimbic dopamine function and thereby play an inhibitory role in the systems by which instrumental behavior is energized toward acquiring primary commodities. General anatomical frameworks for this interaction are presented and future studies that could evaluate it are discussed.
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