Galanin Immunoreactivity in Mouse Basal Forebrain: Sex Differences and Discrete Projections of Galanin-Containing Cells beyond the Blood-Brain Barrier

Rajendren, Gopalan; Levenkova, Nataliya; Gibson, M.E.

doi:10.1159/000054517

Cited by 22 publications

(17 citation statements)

References 38 publications

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“…of galanin mRNA expression in the hypothalamus of the mouse are in good agreement with a recent report of galanin immunoreactivity in the murine basal forebrain, 32 although the relative abundance of galanin peptide reported is at slight variance with our mRNA ®ndings in various regions. It is conceivable that this variance results from methodological differences between the two studies; alternatively, it is possible that it simply re¯ects the fact that levels of mRNA and peptide are regulated differentially in some brain regions, as has been reported in the hypothalamus for cells that are actively secreting peptides.…”

Section: Comparative Distribution and Intensity Of Galanin Expressionsupporting

confidence: 93%

Distribution of galanin messenger RNA-expressing cells in murine brain and their regulation by leptin in regions of the hypothalamus

et al. 2001

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AbstractÐGalanin is widely distributed throughout the mammalian brain and has been implicated in the regulation of food intake, metabolism and reproductionÐfunctions that are also thought to be under the control of leptin. To investigate the possible role of galanin in mediating the physiological effects of leptin in the mouse, we had three experimental objectives: ®rst, to map the distribution of galanin messenger RNA-expressing cells in the brain of the mouse; second, to assess the effects of leptin on galanin gene expression in areas of the brain thought to be involved in the regulation of body weight and reproduction; and third, to determine whether galanin neurons in these regions express leptin receptor messenger RNA. We found the pattern of galanin messenger RNA expression in the mouse brain to be similar, but not identical, to that in the rat. Leptin treatment (2 mg/g for six days) signi®cantly reduced cellular levels of galanin messenger RNA in the hypothalamic periventricular nucleus of leptin-de®cient obese (ob/ob) mice (P , 0.01) by approximately 30%; however, leptin did not appear to in¯uence the expression of galanin in the arcuate or dorsomedial nucleus of the hypothalamus. Galanin-producing neurons in the arcuate, dorsomedial and periventricular nuclei did not appear to express leptin receptor messenger RNA (P . 0.05).These results demonstrate that galanin distribution patterns in the mouse brain are comparable to other species and, yet, possess unique features. In addition, galanin-expressing neurons in the hypothalamic periventricular nucleus are targets for regulation by leptin; however, the effect of leptin on galanin gene expression is likely to be mediated indirectly, perhaps through either proopiomelanocortin-or neuropeptide Y-expressing cells in the hypothalamus. q 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.Key words: neuropeptide, gene regulation, neuroanatomy, in situ hybridization, leptin receptor.Galanin is a 29 amino acid neuropeptide that was originally isolated from the porcine gut. 42 In mammals, galanin is widely distributed throughout the central and peripheral nervous systems. 26 One curious observation about galanin's expression in the brain of mammals is its species speci®city, which is particularly evident in the rat and monkey. For example, in the rat there is little or no expression of galanin in the hippocampus but there are abundant galanin-containing cells in the dorsal raphe. 23,34 In the monkey, however, galanin producing cells are found throughout the hippocampus, yet are absent from the dorsal raphe. 17 To date, there has been no detailed mapping of the distribution of galanin in the mouse brain. Because of the growing importance of the mouse as a genetic model for understanding the brain, it is vital that we know the comparative anatomy of neuropeptide expression in the murine brain and use this information to shed light on the differences and similarities between species. The ®rst objective of this study was to complete a detailed map of the...

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Section: Comparative Distribution and Intensity Of Galanin Expressionsupporting

confidence: 93%

Distribution of galanin messenger RNA-expressing cells in murine brain and their regulation by leptin in regions of the hypothalamus

et al. 2001

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“…36,37 While some studies have reported no sex difference in galanin, 38 others have reported a relatively small sex difference in galanin in both rats 36 and mice. 39 In the present study, two-week-old males expressed more galanin mRNA than females in the amygdala; however, there was no sex difference detected in the number of galaninir cells in either the CMA or the BST in adulthood. Galanin is regulated by circulating testosterone levels, 40 and the adult animals in this study received testosterone-filled implants, whereas, the two-week-old animals did not.…”

Section: Discussioncontrasting

confidence: 62%

Neonatal MeCP2 is important for the organization of sex differences in vasopressin expression

et al. 2012

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“…It is of interest that each NPY receptor mutant also leads to a sexually dimorphic phenotype, as was the case with the GAL Ϫ/Ϫ and GAL Ϫ/Ϫ /NPY Ϫ/Ϫ mutants in the present study. This may not be unexpected, considering that the expression of both galanin and NPY is sexually dimorphic in brain regions involved in energy homeostasis, such as the arcuate nucleus (38,53).…”

Section: Vol 24 2004 Endocrine Deficits In Npy/galanin Knockout Micmentioning

confidence: 99%

Obesity and Endocrine Dysfunction in Mice with Deletions of both Neuropeptide Y and Galanin

Hohmann

Teklemichael

Wynick

et al. 2004

Molecular and Cellular Biology

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Neuropeptide Y (NPY) and galanin have both been implicated in the regulation of body weight, yet mice bearing deletions of either of these molecules have unremarkable metabolic phenotypes. To investigate whether galanin and NPY might compensate for one another, we produced mutants lacking both neuropeptides (GAL ؊/؊ /NPY ؊/؊ ). We found that male GAL ؊/؊ /NPY ؊/؊ mice ate significantly more and were much heavier (30%) than wild-type (WT) controls. GAL ؊/؊ /NPY ؊/؊ mice responded to a high-fat diet by gaining more weight than WT mice gain, and they were unable to regulate their weight normally after a change in diet. GAL ؊/؊ / NPY ؊/؊ mice had elevated levels of leptin, insulin, and glucose, and they lost more weight than WT mice during chronic leptin treatment. Galanin mRNA was increased in the hypothalamus of NPY ؊/؊ mice, providing evidence of compensatory regulation in single mutants. The disruption of energy balance observed in GAL ؊/؊ / NPY ؊/؊ double knockouts is not found in the phenotype of single knockouts of either molecule. The unexpected obesity phenotype may result from the dysregulation of the leptin and insulin systems that normally keep body weight within the homeostatic range.The control of feeding and metabolism in mammals is an exquisitely controlled physiological process, and neuropeptides that regulate energy balance circuits are potential targets for the treatment of obesity. In the brain, neuropeptide Y (NPY) and galanin are both thought to be important regulators of body weight (22). NPY is a potent orexigenic factor (51), and its expression is robustly upregulated during fasting (11). Repeated administration of NPY leads to obesity in rodents (5), perhaps by interaction with other regulatory molecules, such as leptin and insulin (39). Several NPY receptors, including Y1, Y2, Y4, and Y5, have been implicated as transducers of NPY's effects on feeding and body weight (25,28,32,36,44).Galanin is also an orexigenic molecule (10), although its effects in this regard are neither as robust nor as long lived as those of NPY (50). The actions of galanin on energy balance may be related more to either dietary preference or the initiation of hunger responses (1, 45). Galanin has many other roles in neuroendocrine regulation, including modulating the release of growth hormone and the gonadotropins (14, 34, 42). Galanin's role in metabolic homeostasis is unclear, but its robust regulation of (and by) pancreatic hormones implies an important functional role for this neuropeptide (27, 54). Galanin is expressed in various hypothalamic nuclei, including the arcuate (Arc), dorsomedial (DMN), paraventricular, and preoptic areas, which are nodal points in the regulation of energetics and reproduction (8, 30).Considerable evidence suggests roles for both galanin and NPY in the neuroendocrine regulation of energy metabolism and reproductive physiology; however, phenotypic analysis of single deletions of these molecules and their receptors in mice has been incongruous and confusing. For example, despite compel...

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Galanin Immunoreactivity in Mouse Basal Forebrain: Sex Differences and Discrete Projections of Galanin-Containing Cells beyond the Blood-Brain Barrier

Cited by 22 publications

References 38 publications

Distribution of galanin messenger RNA-expressing cells in murine brain and their regulation by leptin in regions of the hypothalamus

Distribution of galanin messenger RNA-expressing cells in murine brain and their regulation by leptin in regions of the hypothalamus

Neonatal MeCP2 is important for the organization of sex differences in vasopressin expression

Obesity and Endocrine Dysfunction in Mice with Deletions of both Neuropeptide Y and Galanin

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