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Mensah ET, Blanco AM, Donini A, Unniappan S. Galanin decreases spontaneous resting contractions and potentiates acetyl choline-induced contractions of goldfish gut. Neuropeptides 2018; 69:92-97. [PMID: 29709304 DOI: 10.1016/j.npep.2018.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/20/2018] [Accepted: 04/22/2018] [Indexed: 12/16/2022]
Abstract
Galanin (GAL) is a 29 amino acid peptide, first identified from the porcine intestine and widely distributed within the brain and peripheral tissues. Among GAL biological functions, its role as a potent appetite-stimulating peptide is probably the most studied. With galanin's established role in the modulation of food intake in fish, this study aims to evaluate the effects of GAL on the intestinal motility of the goldfish, Carassius auratus, using an organ bath system. Our results found that application of GAL to the organ bath causes a significant concentration-dependent decrease in the amplitude of spontaneous contractions of goldfish gut. Preincubations of intestinal strips with acetylcholine (ACh) and GAL showed that GAL increases the force of ACh-induced contractions of the goldfish gut. These results provide the first evidence for a role of GAL in gut motility in goldfish. This also suggests a crosstalk between the effects of GAL and ACh in such functions, thus pointing to a putative joint role between the two molecules. These findings offer novel information that strengthens the role of the galaninergic system in fish feeding.
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Affiliation(s)
- Elsie Tachie Mensah
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Ayelen Melisa Blanco
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.
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Davidson S, Lear M, Shanley L, Hing B, Baizan-Edge A, Herwig A, Quinn JP, Breen G, McGuffin P, Starkey A, Barrett P, MacKenzie A. Differential activity by polymorphic variants of a remote enhancer that supports galanin expression in the hypothalamus and amygdala: implications for obesity, depression and alcoholism. Neuropsychopharmacology 2011; 36:2211-21. [PMID: 21716262 PMCID: PMC3176579 DOI: 10.1038/npp.2011.93] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The expression of the galanin gene (GAL) in the paraventricular nucleus (PVN) and in the amygdala of higher vertebrates suggests the requirement for highly conserved, but unidentified, regulatory sequences that are critical to allow the galanin gene to control alcohol and fat intake and modulate mood. We used comparative genomics to identify a highly conserved sequence that lay 42 kb 5' of the human GAL transcriptional start site that we called GAL5.1. GAL5.1 activated promoter activity in neurones of the PVN, arcuate nucleus and amygdala that also expressed the galanin peptide. Analysis in neuroblastoma cells demonstrated that GAL5.1 acted as an enhancer of promoter activity after PKC activation. GAL5.1 contained two polymorphisms; rs2513280(C/G) and rs2513281(A/G), that occurred in two allelic combinations (GG or CA) where the dominant GG alelle occurred in 70-83 % of the human population. Intriguingly, both SNPs were found to be in LD (R(2) of 0.687) with another SNP (rs2156464) previously associated with major depressive disorder (MDD). Recreation of these alleles in reporter constructs and subsequent magnetofection into primary rat hypothalamic neurones showed that the CA allele was 40 % less active than the GG allele. This is consistent with the hypothesis that the weaker allele may affect food and alcohol preference. The linkage of the SNPs analysed in this study with a SNP previously associated with MDD together with the functioning of GAL5.1 as a PVN and amygdala specific enhancer represent a significant advance in our ability to understand alcoholism, obesity and major depressive disorder.
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Affiliation(s)
- Scott Davidson
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK
| | - Marissa Lear
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK
| | - Lynne Shanley
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK
| | - Benjamin Hing
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK
| | - Amanda Baizan-Edge
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK
| | - Annika Herwig
- The Rowett Institute of Nutrition and Health, Aberdeen, Scotland, UK
| | - John P Quinn
- The Physiological Laboratory, School of Biomedical Sciences, Crown Street, University of Liverpool, Liverpool, UK
| | - Gerome Breen
- MRC SGDP Centre, Institute of Psychiatry, King's College London, DeCrespigny Park, London, UK
| | - Peter McGuffin
- MRC SGDP Centre, Institute of Psychiatry, King's College London, DeCrespigny Park, London, UK
| | - Andrew Starkey
- School of Engineering, Fraser Noble Building, Kings College, University of Aberdeen, Aberdeen, Scotland, UK
| | - Perry Barrett
- The Rowett Institute of Nutrition and Health, Aberdeen, Scotland, UK
| | - Alasdair MacKenzie
- School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK,School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, Scotland, UK, Tel: +44 (0)1224 437380, Fax: +44 (0)1224 555719, E-mail:
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Mensah ET, Volkoff H, Unniappan S. Galanin systems in non-mammalian vertebrates with special focus on fishes. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:243-62. [PMID: 21299073 DOI: 10.1007/978-3-0346-0228-0_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Galanin is a well characterized multifunctional neuropeptide in mammals. Galanin has been identified from several fishes, amphibians, reptiles and birds. A large set of data is available on galanin-like protein distribution and peptide and/or mRNA sequences in non-mammalian vertebrates. Galanin receptor sequences from fishes and birds are known, but its distribution and mechanisms of actions are poorly understood. While some biological actions of galanin are known in non-mammals, the functional role of galanin in lower vertebrates is limited. For example, galanin has been shown to regulate feeding, pituitary hormone secretion and gut motility in fishes. Several aspects of galanin biology remain unknown, yet, there is enough evidence to implicate galanin as an important physiological modulator in lower vertebrates. Majority of the research articles on galanin in non-mammals arise from studies that used fishes. The objective of this chapter is to provide a summarized discussion of current knowledge on galanin peptide and gene sequences and organization, distribution of galanin gene and protein, and physiological functions of galanin in non-mammalian vertebrates with a special focus on fishes.
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Affiliation(s)
- Elsie Tachie Mensah
- Laboratory of Integrative Neuroendocrinology, Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
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Degerman A, Chun D, Nguyen TB, Bravo DT, Alanis J, Rökaeus A, Waschek JA. Local action of estrogen and thyroid hormone on vasoactive intestinal peptide (VIP) and galanin gene expression in the rat anterior pituitary. Neuropeptides 2002; 36:50-7. [PMID: 12147214 DOI: 10.1054/npep.2002.0886] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Neuropeptides act within the pituitary as autocrine or paracrine factors, modulating the synthesis and release of primary pituitary hormones, and possibly regulating cell proliferation and/or plasticity. Manipulation of the endocrine status of rats produces dramatic long-term changes in the pituitary expression of several peptides, including the neuropeptides galanin and vasoactive intestinal peptide (VIP). Whether or not these changes are caused indirectly by hypothalamic factors, or by hormone actions directly in the pituitary, has been only partially addressed. To determine if estrogen or thyroid hormone can act directly within the pituitary to regulate VIP and galanin gene expression, cultured female rat pituitary cells were treated with 10 nM 1,17 beta-estradiol (E2) or triiodothyronine (T(3)). E2 treatment for three days resulted in an approximate 5-fold and 7-fold increase in VIP and galanin mRNA, respectively. In contrast, T(3) treatment reduced the mRNA levels of these neuropeptides to approximately 40% and 30% of control values. A time course study indicated that the actions of estrogen on VIP and galanin mRNA, and of thyroid hormone on VIP mRNA were readily apparent after 24h. The rat pituitary tumor cell line RC-4B/C was found to express easily detectable levels of galanin but not VIP mRNA. Galanin gene expression in these cells was moderately increased by E2 and decreased by T(3). Transfection of a series of luciferase plasmids containing 5 kb to 131 bp of the bovine galanin promoter fused to luciferase revealed cell-type specific enhancer sequences located between -452 and -131 bp of the galanin gene transcription start site. However, transfected plasmids were minimally responsive to E2 and T(3) treatment. Overall the results suggest that E2 and T(3) exert significant local actions in the pituitary on VIP and galanin gene expression. The bovine galanin gene fragment used in these studies contains a potential pituitary cell-type specific enhancer, but appears to lack strong E2-and T(3)-responsive sequences.
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MESH Headings
- Animals
- Cattle
- Cells, Cultured/drug effects
- Enhancer Elements, Genetic
- Estradiol/pharmacology
- Female
- Galanin/biosynthesis
- Galanin/genetics
- Gene Expression Regulation/drug effects
- Genes, Reporter
- Genes, Synthetic
- Luciferases/biosynthesis
- Luciferases/genetics
- Mice
- Organ Specificity
- Pituitary Gland, Anterior/drug effects
- Pituitary Neoplasms/pathology
- Promoter Regions, Genetic
- RNA, Messenger/biosynthesis
- Rats
- Rats, Inbred F344
- Rats, Sprague-Dawley
- Recombinant Fusion Proteins/biosynthesis
- Transfection
- Triiodothyronine/pharmacology
- Tumor Cells, Cultured
- Vasoactive Intestinal Peptide/metabolism
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Affiliation(s)
- A Degerman
- Department of Psychiatry and Mental Retardation Research Center, University of California at Los Angeles, CA 90024, USA
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Wells T, Carter DA. Genetic engineering of neural function in transgenic rodents: towards a comprehensive strategy? J Neurosci Methods 2001; 108:111-30. [PMID: 11478971 DOI: 10.1016/s0165-0270(01)00391-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
As mammalian genome projects move towards completion, the attention of molecular neuroscientists is currently moving away from gene identification towards both cell-specific gene expression patterns (neuronal transcriptions) and protein expression/interactions (neuronal proteomics). In the long term, attention will increasingly be directed towards experimental interventions which are able to question neuronal function in a sophisticated manner that is cognisant of both transcriptomic and proteomic organization. Central to this effort will be the application of a new generation of transgenic approaches which are now evolving towards an appropriate level of molecular, temporal and spatial resolution. In this review, we summarize recent developments in transgenesis, and show how they have been applied in the principal model species for neuroscience, namely rats and mice. Current concepts of transgene design are also considered together with an overview of new genetically-encoded tools including both cellular indicators such as fluorescent activity reporters, and cellular regulators such as dominant negative signalling factors. Application of these tools in a whole animal context can be used to question both basic concepts of brain function, and also current concepts of underlying dysfuction in neurological diseases.
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Affiliation(s)
- T Wells
- School of Biosciences, Cardiff University, PO Box 911, Museum Avenue, Cardiff CF10 3US, UK
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Rökaeus A, Jiang K, Spyrou G, Waschek JA. Transcriptional control of the galanin gene. Tissue-specific expression and induction by NGF, protein kinase C, and estrogen. Ann N Y Acad Sci 1998; 863:1-13. [PMID: 9928155 DOI: 10.1111/j.1749-6632.1998.tb10679.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Galanin is a neuropeptide widely expressed in the central and peripheral nervous system where it acts as a neurotransmitter/neuromodulator and possibly an immunoregulator and growth factor. Galanin gene expression is highly regulated during development and by certain hormones and injury situations. We have examined transcriptional control mechanisms for this gene using chimeric bovine galanin/luciferase reporter genes. These were analyzed in cultured cells and in transgenic mice. The studies reveal that enhancer and silencer sequences are involved in conferring cell- and tissue-specific expression, and that specific elements close to the promoter are responsible for nerve growth factor and protein kinase C induction. So far, the studies have not revealed sequences on the bovine gene that mediate the action of estrogen.
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Affiliation(s)
- A Rökaeus
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, Stockholm, Sweden.
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