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Autio J, Stenbäck V, Gagnon DD, Leppäluoto J, Herzig KH. (Neuro) Peptides, Physical Activity, and Cognition. J Clin Med 2020; 9:jcm9082592. [PMID: 32785144 PMCID: PMC7464334 DOI: 10.3390/jcm9082592] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
Regular physical activity (PA) improves cognitive functions, prevents brain atrophy, and delays the onset of cognitive decline, dementia, and Alzheimer’s disease. Presently, there are no specific recommendations for PA producing positive effects on brain health and little is known on its mediators. PA affects production and release of several peptides secreted from peripheral and central tissues, targeting receptors located in the central nervous system (CNS). This review will provide a summary of the current knowledge on the association between PA and cognition with a focus on the role of (neuro)peptides. For the review we define peptides as molecules with less than 100 amino acids and exclude myokines. Tachykinins, somatostatin, and opioid peptides were excluded from this review since they were not affected by PA. There is evidence suggesting that PA increases peripheral insulin growth factor 1 (IGF-1) levels and elevated serum IGF-1 levels are associated with improved cognitive performance. It is therefore likely that IGF-1 plays a role in PA induced improvement of cognition. Other neuropeptides such as neuropeptide Y (NPY), ghrelin, galanin, and vasoactive intestinal peptide (VIP) could mediate the beneficial effects of PA on cognition, but the current literature regarding these (neuro)peptides is limited.
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Affiliation(s)
- Juho Autio
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
| | - Ville Stenbäck
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Biocenter Oulu, 90220 Oulu, Finland
| | - Dominique D. Gagnon
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Laboratory of Environmental Exercise Physiology, School of Human Kinetics, Laurentian University, Sudbury, ON P3E 2C6, Canada
- Center of Research in Occupational Safety and Health, Laurentian University, Sudbury, ON P3E 2C6, Canada
| | - Juhani Leppäluoto
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
| | - Karl-Heinz Herzig
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Department of Gastroenterology and Metabolism, Poznan University of Medical Sciences, 60-572 Poznan, Poland
- Correspondence:
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Ihnatko R, Theodorsson E. Short N-terminal galanin fragments are occurring naturally in vivo. Neuropeptides 2017; 63:1-13. [PMID: 28434790 DOI: 10.1016/j.npep.2017.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/08/2017] [Accepted: 03/31/2017] [Indexed: 10/19/2022]
Abstract
UNLABELLED The galanin family currently consists of four peptides, namely galanin, galanin-message associated peptide, galanin-like peptide and alarin. Unlike galanin that signals through three different G protein-coupled receptors; GAL1, GAL2, and GAL3, binding at its N-terminal end, the cognate receptors for other members of the galanin family are currently unknown. Research using short N-terminal galanin fragments generated either by enzymatic cleavage or solid-phase synthesis has revealed differences in their receptor binding properties exerting numerous biological effects distinct from galanin(1-29) itself. Our studies on tissue extracts derived from rat small intestine and bovine gut using chromatographic techniques and sensitive galanin(1-16)-specific radioimmunoassay revealed the presence of immunoreactive compounds reacting with antiserum against galanin(1-16) distributed in distinct elution volumes. These results suggested a possible presence of short N-terminal galanin fragments also in vivo. Moreover, employing immunoaffinity chromatography and reverse-phase high performance liquid chromatography (HPLC) followed by mass spectrometry allowed specific enrichment of these immunoreactive compounds from rat tissues and identification of their molecular structure. Indeed, our study revealed presence of several distinct short N-terminal galanin sequences in rat tissue. To prove their receptor binding, four of the identified sequences were synthetized, namely, galanin(1-13), galanin(1-16), galanin(1-20), galanin(6-20), and tested on coronal rat brain sections competing with 125I-labeled galanin(1-29). Our autoradiographs confirmed that galanin(1-13), galanin(1-16), and galanin(1-20) comprehensively displaced 125I-galanin(1-29) but galanin(6-20) did not. Here we show, for the first time, that short N-terminal galanin fragments occur naturally in rat tissues and that similar or identical galanin sequences can be present also in tissues of other species. BIOLOGICAL SIGNIFICANCE This study is first to provide an evidence of the presence of short N-terminal galanin fragments in vivo in a biological system and provides further foundations for the previous studies using synthetized short N-terminal galanin fragments.
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Affiliation(s)
- Robert Ihnatko
- Department of Clinical Chemistry, Department of Clinical and Experimental Medicine, Linköping University, 58285 Linköping, Sweden.
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Department of Clinical and Experimental Medicine, Linköping University, 58285 Linköping, Sweden
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Abstract
Since the neuropeptide galanin’s discovery in 1983, information has accumulated that implicates it in a wide range of functions, including pain sensation, stress responses, appetite regulation, and learning and memory. This article reviews the evidence for specific functions of galanin in cognitive processes. Consistencies as well as gaps in the literature are organized around basic questions of methodology and theory. This review shows that although regularities are evident in the observed behavioral effects of galanin across several methods for measuring learning and memory, generalization from these findings is tempered with concerns about confounds and a restricted range of testing conditions. Furthermore, it is revealed that many noncognitive behavioral constructs that are relevant for assessing potential roles for galanin in cognition have not been thoroughly examined. The review concludes by laying out how future theory and experimental work can overcome these concerns and confidently define the nature of the association of galanin with particular cognitive constructs.
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Murtishaw AS, Heaney CF, Bolton MM, Sabbagh JJ, Langhardt MA, Kinney JW. Effect of acute lipopolysaccharide-induced inflammation in intracerebroventricular-streptozotocin injected rats. Neuropharmacology 2016; 101:110-22. [DOI: 10.1016/j.neuropharm.2015.08.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/03/2015] [Accepted: 08/26/2015] [Indexed: 12/25/2022]
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Barreda-Gómez G, Lombardero L, Giralt MT, Manuel I, Rodríguez-Puertas R. Effects of galanin subchronic treatment on memory and muscarinic receptors. Neuroscience 2015; 293:23-34. [PMID: 25732139 DOI: 10.1016/j.neuroscience.2015.02.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/13/2015] [Accepted: 02/20/2015] [Indexed: 11/28/2022]
Abstract
The cholinergic pathways, which originate in the basal forebrain and are responsible for the control of different cognitive processes including learning and memory, are also regulated by some neuropeptides. One of these neuropeptides, galanin (GAL), is involved in both neurotrophic and neuroprotective actions. The present study has evaluated in rats the effects on cognition induced by a subchronic treatment with GAL by analyzing the passive avoidance response, and the modulation of muscarinic cholinergic receptor densities and activities. [(3)H]-N-methyl-scopolamine, [(3)H]-oxotremorine, and [(3)H]-pirenzepine were used to quantify the density of muscarinic receptors (MRs) and the stimulation of the binding of guanosine 5'-(γ-[(35)S]thio)triphosphate by the muscarinic agonist, carbachol, to determine their functionality. Some cognitive deficits that were induced by the administration of artificial cerebrospinal fluid (aCSF) (i.c.v. aCSF 2 μl/min, once a day for 6 days) were not observed in the animals also treated with GAL (i.c.v. 1.5 mmol in aCSF, 2 μl/min, once a day for 6 days). GAL modulates the changes in M1 and M2 MR densities observed in the rats treated with aCSF, and also increased their activity mediated by G(i/o) proteins in specific areas of the dorsal and ventral hippocampus. The subchronic administration of the vehicle was also accompanied by an increased number of positive fibers and cells for GAL around the cortical tract of the cannula used, but that was not the case in GAL-treated rats. In addition, the increase of GAL receptor density in the ventral hippocampus and entorhinal cortex in the aCSF group was avoided when GAL was administered. The number of acetylcholinesterase (AChE)-positive neurons was decreased in the nucleus basalis of Meynert of both GAL- and aCSF-treated animals. In summary, GAL improves memory-related abilities probably through the modulation of MR density and/or efficacy in hippocampal areas.
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Affiliation(s)
- G Barreda-Gómez
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), E-48940 Leioa, Vizcaya, Spain
| | - L Lombardero
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), E-48940 Leioa, Vizcaya, Spain
| | - M T Giralt
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), E-48940 Leioa, Vizcaya, Spain
| | - I Manuel
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), E-48940 Leioa, Vizcaya, Spain
| | - R Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), E-48940 Leioa, Vizcaya, Spain.
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Beck B, Pourié G. Ghrelin, neuropeptide Y, and other feeding-regulatory peptides active in the hippocampus: role in learning and memory. Nutr Rev 2013; 71:541-61. [PMID: 23865799 DOI: 10.1111/nure.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The hippocampus is a brain region of primary importance for neurogenesis, which occurs during early developmental states as well as during adulthood. Increases in neuronal proliferation and in neuronal death with age have been associated with drastic changes in memory and learning. Numerous neurotransmitters are involved in these processes, and some neuropeptides that mediate neurogenesis also modulate feeding behavior. Concomitantly, feeding peptides, which act primarily in the hypothalamus, are also present in the hippocampus. This review aims to ascertain the role of several important feeding peptides in cognitive functions, either through their local synthesis in the hippocampus or through their actions via specific receptors in the hippocampus. A link between neurogenesis and the orexigenic or anorexigenic properties of feeding peptides is discussed.
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Affiliation(s)
- Bernard Beck
- INSERM U954, Nutrition, Génétique et Expositions aux Risques Environnementaux, Faculté de Médecine, Vandœuvre, France.
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Sabbagh JJ, Heaney CF, Bolton MM, Murtishaw AS, Ure JA, Kinney JW. Administration of Donepezil Does Not Rescue Galanin-Induced Spatial Learning Deficits. Int J Neurosci 2012; 122:742-7. [DOI: 10.3109/00207454.2012.721411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Sabbagh JJ, Kinney JW, Cummings JL. Animal systems in the development of treatments for Alzheimer's disease: challenges, methods, and implications. Neurobiol Aging 2012; 34:169-83. [PMID: 22464953 DOI: 10.1016/j.neurobiolaging.2012.02.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/25/2012] [Accepted: 02/26/2012] [Indexed: 11/18/2022]
Abstract
Substantial resources and effort have been invested into the development of therapeutic agents for Alzheimer's disease (AD) with mixed and limited success. Research into the etiology of AD with animal models mimicking aspects of the disorder has substantially contributed to the advancement of potential therapies. Although these models have shown utility in testing novel therapeutic candidates, large variability still exists in terms of methodology and how the models are utilized. No model has yet predicted a successful disease-modifying therapy for AD. This report reviews several of the widely accepted transgenic and nontransgenic animal models of AD, highlighting the pathological and behavioral characteristics of each. Methodological considerations for conducting preclinical animal research are discussed, such as which behavioral tasks and histological markers may be associated with the greatest insight into therapeutic benefit. An overview of previous and current therapeutic interventions being investigated in AD models is presented, with an emphasis on factors that may have contributed to failure in past clinical trials. Finally, we propose a multitiered approach for investigating candidate therapies for AD that may reduce the likelihood of inappropriate conclusions from models and failed trials in humans.
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Affiliation(s)
- Jonathan J Sabbagh
- Behavioral Neuroscience Laboratory, University of Nevada, Las Vegas, NV, USA
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Abbosh C, Lawkowski A, Zaben M, Gray W. GalR2/3 mediates proliferative and trophic effects of galanin on postnatal hippocampal precursors. J Neurochem 2011; 117:425-36. [PMID: 21281311 DOI: 10.1111/j.1471-4159.2011.07204.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: 01/11/2023]
Abstract
Understanding how neural activity is functionally linked to the stem cell niche, is assuming ever increasing importance as hippocampal neurogenesis is shown to be important for modulating the behavioural responses to stress and for certain forms of learning and memory. Neuropeptides such as neuropeptide Y and vasoactive intestinal peptide have emerged as important mediators for signalling local interneuron activity to subgranular zone precursors, however, little is known regarding the effects of neuropeptides that are extrinsic modulators of hippocampal information processing. Here, we show that the galanin GalR2/3 agonist Gal2-11 is both trophic and proliferative for postnatal subgranular precursors and proliferating neuroblasts at 10 nM and is purely trophic at doses as low as 100 pM. We found no effect mediated via GalR1. As galanin is co-released from noradrenergic and serotonergic projection neurons to the dentate gyrus, these findings support a direct effect of galanin on hippocampal neurogenesis, which may partly mediate its antidepressant effect via GalR2/3 receptors.
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Affiliation(s)
- Christopher Abbosh
- Division of Clinical Neurosciences, University of Southampton, Southampton, UK
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Shen PJ, Gundlach AL. Galanin systems and ischemia: peptide and receptor plasticity in neurons and oligodendroglial precursors. EXPERIENTIA SUPPLEMENTUM (2012) 2011; 102:209-21. [PMID: 21299071 DOI: 10.1007/978-3-0346-0228-0_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cerebral cortex contains few if any galanin neurons, but receives galanin-ergic inputs from subcortical areas. Apart from our earlier study on the response to cortical spreading depression, little is known about the presence and function of galanin in normal or injured cortex and to gain more insight into its possible roles, we investigated the temporal effects of focal ischemia on the expression of galanin and galanin receptors (GalRs). Focal ischemia induced in the rat by unilateral middle cerebral artery occlusion increased galanin and GalR1 mRNAs in penumbral/undamaged areas on the first and second day post-ischemia, while increased GalR2 mRNA was observed in the same regions only on the second day. Immunohistochemical studies revealed galanin immunoreactive neurons in the frontal/ cingulate cortex and abundant galanin-immunoreactivity in nerve axons/fibres within the penumbral areas, between the third and the seventh day after ischemia. Galanin mRNA and immunoreactivity was also increased in a population of small cells thought to be NG2-positive oligodendrocyte precursors. Up-regulation of galanin and GalRs in various cell populations following severe ischemic injury further demonstrates the marked plasticity of galanin and GalR1/2 expression after brain injury, and together with data reported elsewhere in this volume, suggests a functional role for galanin signalling in such pathophysiological conditions.
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Affiliation(s)
- Pei-Juan Shen
- Florey Neuroscience Institutes, The University of Melbourne, Melbourne, VIC 3010, Australia
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Ball ER, Caniglia MK, Wilcox JL, Overton KA, Burr MJ, Wolfe BD, Sanders BJ, Wisniewski AB, Wrenn CC. Effects of genistein in the maternal diet on reproductive development and spatial learning in male rats. Horm Behav 2010; 57:313-22. [PMID: 20053350 PMCID: PMC2834867 DOI: 10.1016/j.yhbeh.2009.12.013] [Citation(s) in RCA: 29] [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] [Received: 08/10/2009] [Revised: 12/27/2009] [Accepted: 12/29/2009] [Indexed: 10/20/2022]
Abstract
Endocrine disruptors, chemicals that disturb the actions of endogenous hormones, have been implicated in birth defects associated with hormone-dependent development. Phytoestrogens are a class of endocrine disruptors found in plants. In the current study we examined the effects of exposure at various perinatal time periods to genistein, a soy phytoestrogen, on reproductive development and learning in male rats. Dams were fed genistein-containing (5 mg/kg feed) food during both gestation and lactation, during gestation only, during lactation only, or during neither period. Measures of reproductive development and body mass were taken in the male offspring during postnatal development, and learning and memory performance was assessed in adulthood. Genistein exposure via the maternal diet decreased body mass in the male offspring of dams fed genistein during both gestation and lactation, during lactation only, but not during gestation only. Genistein decreased anogenital distance when exposure was during both gestation and lactation, but there was no effect when exposure was limited to one of these time periods. Similarly, spatial learning in the Morris water maze was impaired in male rats exposed to genistein during both gestation and lactation, but not in rats exposed during only one of these time periods. There was no effect of genistein on cued or contextual fear conditioning. In summary, the data indicate that exposure to genistein through the maternal diet significantly impacts growth in male offspring if exposure is during lactation. The effects of genistein on reproductive development and spatial learning required exposure throughout the pre- and postnatal periods.
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Affiliation(s)
- Evan R. Ball
- Department of Pharmaceutical, Biomedical & Administrative Sciences, College of Pharmacy and Health Sciences, Drake University, Des Moines, IA, 50311 USA
| | | | - Jenna L. Wilcox
- Neuroscience Program, Drake University, Des Moines, IA, 50311 USA
| | - Karla A. Overton
- Neuroscience Program, Drake University, Des Moines, IA, 50311 USA
| | - Marra J. Burr
- Department of Pharmaceutical, Biomedical & Administrative Sciences, College of Pharmacy and Health Sciences, Drake University, Des Moines, IA, 50311 USA
- Neuroscience Program, Drake University, Des Moines, IA, 50311 USA
| | - Brady D. Wolfe
- Department of Pharmaceutical, Biomedical & Administrative Sciences, College of Pharmacy and Health Sciences, Drake University, Des Moines, IA, 50311 USA
| | - Brian J. Sanders
- Neuroscience Program, Drake University, Des Moines, IA, 50311 USA
- Department of Psychology, Drake University, Des Moines, IA 50311 USA
| | - Amy B. Wisniewski
- Section of Pediatric Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73117 USA
| | - Craige C. Wrenn
- Department of Pharmaceutical, Biomedical & Administrative Sciences, College of Pharmacy and Health Sciences, Drake University, Des Moines, IA, 50311 USA
- Neuroscience Program, Drake University, Des Moines, IA, 50311 USA
- To whom correspondence should be addressed: Craige C. Wrenn, Ph.D., 109 Fitch Hall, 2507 University Avenue, College of Pharmacy and Health Sciences, Drake University, Des Moines, IA 50311, Voice: 515-271-3326, Fax: 515-271-1867,
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Galanin impairs cognitive abilities in rodents: relevance to Alzheimer's disease. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:133-41. [PMID: 21299066 DOI: 10.1007/978-3-0346-0228-0_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The neuropeptide galanin and its receptors are localized in brain pathways that mediate learning and memory. Central microinjection of galanin impairs performance of a variety of cognitive tasks in rats. Transgenic mice overexpressing galanin display deficits in some learning and memory tests. The inhibitory role of galanin in cognitive processes, taken together with the fact that overexpression of galanin occurs in Alzheimer's disease, suggests that galanin antagonists may offer a novel therapeutic approach to treat memory loss in patients suffering from Alzheimer's.
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Seigers R, Schagen SB, Coppens CM, van der Most PJ, van Dam FS, Koolhaas JM, Buwalda B. Methotrexate decreases hippocampal cell proliferation and induces memory deficits in rats. Behav Brain Res 2009; 201:279-84. [DOI: 10.1016/j.bbr.2009.02.025] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 02/18/2009] [Accepted: 02/24/2009] [Indexed: 11/30/2022]
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Kinney JW, Sanchez-Alavez M, Barr AM, Criado JR, Crawley JN, Behrens MM, Henriksen SJ, Bartfai T. Impairment of memory consolidation by galanin correlates with in vivo inhibition of both LTP and CREB phosphorylation. Neurobiol Learn Mem 2009; 92:429-38. [PMID: 19531380 DOI: 10.1016/j.nlm.2009.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 05/19/2009] [Accepted: 06/08/2009] [Indexed: 11/30/2022]
Abstract
Changes in the state of CREB phosphorylation and in LTP in the hippocampus have been associated with learning and memory. Here we show that galanin, the neuropeptide released in the hippocampal formation from cholinergic and noradrenergic fibers, that has been shown to produce impairments in memory consolidation in the Morris water maze task inhibits both LTP and CREB phosphorylation in the rat hippocampus in vivo. While there are many transmitters regulating CREB phosphorylation none has been shown to suppress behaviorally-induced hippocampal CREB phosphorylation as potently as galanin. The in vivo inhibition of dentate gyrus-LTP and of CREB phosphorylation by the agonist occupancy of GalR1 and GalR2-type galanin receptors provides strong in vivo cellular and molecular correlates to galanin-induced learning deficits and designates galanin as a major regulator of the memory consolidation process.
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Affiliation(s)
- Jefferson W Kinney
- Department of Psychology, University of Nevada, Las Vegas, NV 89154-5030, USA.
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Kozlovsky N, Matar MA, Kaplan Z, Zohar J, Cohen H. The role of the galaninergic system in modulating stress-related responses in an animal model of posttraumatic stress disorder. Biol Psychiatry 2009; 65:383-91. [PMID: 19095221 DOI: 10.1016/j.biopsych.2008.10.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 10/05/2008] [Accepted: 10/07/2008] [Indexed: 11/26/2022]
Abstract
BACKGROUND Converging evidence implicates the regulatory neuropeptide galanin in anxiety- and depression-related behaviors, through modulation of neuroendocrine, serotonergic, and noradrenergic systems. This study examined the relationship between stress-induced posttraumatic stress disorder (PTSD)-like behavioral response patterns in rats and galanin mRNA levels in key brain areas and the effects of acute phase pharmacologic manipulation using an agonist (galnon) on behavioral, physiologic, and response patterns of brain-derived neurotrophic factor (BDNF) and 5-hydroxytryptamine-1A (5HT-1A). METHOD Galanin mRNA expression was assessed in the frontal cortex and hippocampus in the short- and long-term (30 min and 7 days) after exposure to predator scent stress. The effects of intraperitoneal galnon .5 mg/kg versus saline 1 hour postexposure on behavioral tests (elevated plus maze and acoustic startle response) were evaluated 7 days later. Trauma-cue response, circulating corticosterone, and localized brain expression of 5HT-1A receptors and BDNF were subsequently assessed. All data were analyzed in relation to individual behavior patterns. RESULTS Whereas animals with minimal behavioral disruption displayed a lasting upregulation of galanin mRNA in the hippocampal CA1 area, those with extreme behavioral responses displayed downregulation in both CA1 and frontal cortex. Immediate postexposure treatment with galnon significantly reduced prevalence rates of extreme responders, reduced trauma-cue freezing responses, corrected the corticosterone response, and increased CA1 expression of 5HT-1A and BDNF mRNA compared with saline controls. CONCLUSIONS Galanin is actively involved in the neurobiological response to predator scent stress with resilience/recovery after stress exposure and thus warrants further study as a potential therapeutic avenue for the treatment of anxiety-related disorders.
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Affiliation(s)
- Nitsan Kozlovsky
- State of Israel Ministry of Health, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Abstract
The mechanisms underlying responses to drugs of abuse have been widely investigated; however, less is known about pathways normally protective against the development of drug reinforcement. These pathways are also important since they may regulate individual differences in vulnerability to addiction. The neuropeptide galanin and its binding sites are expressed in brain areas important for drug reward. Previous studies have shown that centrally infused galanin attenuates morphine place preference and peripheral injection of galnon, a galanin agonist, decreases opiate withdrawal signs. The current studies in galanin knockout (GKO) mice examined the hypothesis that galanin is an endogenous negative regulator of opiate reward and identified downstream signaling pathways regulated by galanin. We show that GKO mice demonstrate increased locomotor activation following morphine administration, which is inhibited by acute administration of galnon. GKO mice also show enhanced morphine place preference, supporting the idea that galanin normally antagonizes opiate reward. In addition, morphine-induced ERK1/2 phosphorylation was increased in the VTA of both wild-type and GKO mice, but only the GKO mice showed increases in ERK1/2 and CREB phosphorylation in the amygdala or nucleus accumbens. Furthermore, a single systemic injection of galnon in GKO mice was sufficient to reverse some of the biochemical changes brought about by morphine administration. These data suggest that galanin normally attenuates behavioral and neurochemical effects of opiates; thus, galanin agonists may represent a new class of therapeutic targets for opiate addiction.
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Abstract
The neuropeptide galanin and its receptors are localized in brain pathways mediating learning and memory. Central microinjection of galanin impairs performance of a variety of cognitive tasks in rats. Transgenic mice overexpressing galanin display deficits in some learning and memory tests. The inhibitory role of galanin in cognitive processes, taken together with the overexpression of galanin in Alzheimer's disease, suggests that galanin antagonists may offer a novel therapeutic approach to treat memory loss in Alzheimer's patients.
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Affiliation(s)
- J N Crawley
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Porter Neuroscience Research, Center Building 35, Room 1C-903, Mail Code 3730, Bethesda, Maryland 20892-3730, USA.
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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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Micale V, Leggio GM, Mazzola C, Drago F. Cognitive effects of SL65.0155, a serotonin 5-HT4 receptor partial agonist, in animal models of amnesia. Brain Res 2006; 1121:207-15. [PMID: 17011531 DOI: 10.1016/j.brainres.2006.08.108] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 08/27/2006] [Accepted: 08/29/2006] [Indexed: 11/19/2022]
Abstract
Given that several data suggest the involvement of serotonergic (5-HT) system, particularly the serotonin 5-HT(4) receptors, in memory processes; this study was undertaken to investigate the role of serotonin 5-HT(4) receptors in different experimental models of amnesia in male Swiss mice or in male Sprague-Dawley rats, tested in learning and memory tasks. Amnesia was induced in mice by intracerebroventricular (i.c.v.) injection of beta-amyloid 1-42 fragment (BAP 1-42; 400 pmol/mouse) or of galanin (GAL) 1-29 (3 microg/mouse). Another group of animals was exposed to carbon monoxide (CO). Treatments were made 14 days, 15 min or 8 days prior to the learning trial of a step-through passive avoidance paradigm, respectively. Latency to re-enter the dark box appeared to be reduced in all treatment groups. Intraperitoneal (i.p.) administration of SL65.0155 (5-(8-amino-7-chloro-2,3-dihydro-1,4-benzodioxin-5-yl)-3-[1-(2-phenylethyl)-4-piperidinyl]-1,3,4-oxadiazol-2(3H)-one-monohydrochloride), a serotonin 5-HT(4) receptor partial agonist (1 mg/kg/day), for 7 days prior to the learning trial, inhibited the amnesic effect of both peptides increasing the latency to re-enter the dark box also in mice exposed to CO. In rats with ibotenate-induced lesions of the nucleus basalis magnocellularis (NBM) or prenatally exposed to methylazoxymethanol (MAM), SL65.0155 (1 mg/kg/day, i.p.) administered for 7 days, improved the learning and memory capacity in animals tested in shuttle-box active avoidance and radial maze tests. These findings give further support to the hypothesis of SL65.0155 cognition-enhancing activity across a range of tasks.
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Affiliation(s)
- Vincenzo Micale
- Department of Experimental and Clinical Pharmacology, University of Catania, Viale A. Doria, 6, 95125 Catania, Italy
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Wrenn CC, Turchi JN, Schlosser S, Dreiling JL, Stephenson DA, Crawley JN. Performance of galanin transgenic mice in the 5-choice serial reaction time attentional task. Pharmacol Biochem Behav 2006; 83:428-40. [PMID: 16626795 DOI: 10.1016/j.pbb.2006.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Revised: 02/22/2006] [Accepted: 03/05/2006] [Indexed: 01/21/2023]
Abstract
The neuropeptide galanin impairs learning and memory in rodents. The mechanism underlying the cognitive effects of galanin may be related to inhibitory effects of galanin on cholinergic transmission. As cholinergic function is thought to modulate sustained attention, the present study examined whether galanin-overexpressing transgenic mice have impairments in sustained attention. Galanin transgenic (GAL-tg) mice and wild-type (WT) littermate controls were trained in a 5-choice serial reaction time task, modified to assess sustained attention. GAL-tg and WT mice performed similarly during acquisition with respect to accuracy, total omissions, and response speed. Attentional mechanisms were challenged by parametric changes including increased event rate, event asynchrony, or decreased stimulus duration. Singly, these challenges did not differentially affect performance between genotypes. Concurrent administration of these challenges, which represents an optimal test of sustained attention, also had similar effects on GAL-tg and WT mice. When stimulus discriminability was reduced by constant illumination of the house light, GAL-tg mice omitted more trials than WT mice, but other measures of performance did not differ by genotype. Moreover, intraventricular injection of galanin in WT mice did not affect sustained attention. These data indicate that previously reported learning and memory effects of galanin are not secondary to attentional dysfunction.
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Affiliation(s)
- Craige C Wrenn
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892, USA.
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21
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Wang JH, Fu Y, Wilson FAW, Ma YY. Ketamine affects memory consolidation: Differential effects in T-maze and passive avoidance paradigms in mice. Neuroscience 2006; 140:993-1002. [PMID: 16600517 DOI: 10.1016/j.neuroscience.2006.02.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 02/16/2006] [Accepted: 02/24/2006] [Indexed: 11/29/2022]
Abstract
The effects of ketamine, an N-methyl-D-aspartate (NMDA) antagonist, on memory in animals have been limited to the sub-anesthetic dose given prior to training in previous studies. We evaluated the effects of post-training anesthetic doses of ketamine to selectively manipulate memory consolidation, and the effect of pre-retention sub-anesthetic doses of ketamine on memory retrieval in passive avoidance and T-maze tasks in mice. Repeated post-training anesthetic doses of ketamine impaired the consolidation of memory in the T-maze but not in passive avoidance paradigms. This impairment was not permanent but diminished 1-2 days after ketamine withdrawal. Sub-anesthetic post-training doses of ketamine (5 mg/kg) had no effect on memory consolidation, and larger doses (10, 20 and 50 mg/kg) did not influence the retrieval of memory in the T-maze. The data suggest that repeated anesthetic doses of ketamine block NMDA receptors and affect memory consolidation. Moreover, NMDA mechanisms antagonized by ketamine appear to be selectively involved in spatial (T-maze) memory mechanisms but may not be necessary for non-spatial (passive avoidance) memory consolidation.
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Affiliation(s)
- J H Wang
- Section of Cognitive Brain Research and Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, PR China
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Zheng K, Kuteeva E, Xia S, Bartfai T, Hökfelt T, Xu ZQD. Age-related impairments of synaptic plasticity in the lateral perforant path input to the dentate gyrus of galanin overexpressing mice. Neuropeptides 2005; 39:259-67. [PMID: 15944020 DOI: 10.1016/j.npep.2005.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Accepted: 02/15/2005] [Indexed: 11/17/2022]
Abstract
In the present study, electrophysiological recordings were made from hippocampal slices obtained from mice overexpressing galanin under the promoter for the platelet-derived growth factor-B (GalOE mice). In these mice, a particularly strong galanin expression is seen in the granule cell layer/mossy fibers. Paired-pulse facilitation (PPF) of excitatory postsynaptic field potentials (fEPSPs) at the lateral perforant path (LPP)-dentate gyrus synapses was elicited in the dentate gyrus after stimulation with different interpulse intervals. Slices from young adult wild-type (WT) animals showed significant PPF of the 2nd EPSP evoked with paired-pulse stimuli, while PPF was reduced in slices from young adult GalOE mice, as well as aged WT mice, but were not observed at all in slices from aged GalOE animals. Application of the putative galanin antagonist M35 increased PPF in slices from aged WT mice as well as from adult and aged GalOE mice, but had no effect in slices taken from young adult WT mice. These data indicate that galanin is involved in hippocampal synaptic plasticity, in particular in age-related reduction of synaptic plasticity in the LPP input to the dentate gyrus. Galaninergic mechanisms may therefore represent therapeutic targets for treatment of age-related memory deficits and Alzheimer's disease.
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Affiliation(s)
- Kang Zheng
- Department of Neuroscience, Karolinska Institutet, S-171 71, Stockholm, Sweden
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Rustay NR, Wrenn CC, Kinney JW, Holmes A, Bailey KR, Sullivan TL, Harris AP, Long KC, Saavedra MC, Starosta G, Innerfield CE, Yang RJ, Dreiling JL, Crawley JN. Galanin impairs performance on learning and memory tasks: findings from galanin transgenic and GAL-R1 knockout mice. Neuropeptides 2005; 39:239-43. [PMID: 15944016 DOI: 10.1016/j.npep.2004.12.026] [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] [Received: 12/17/2004] [Accepted: 12/17/2004] [Indexed: 02/04/2023]
Abstract
Galanin (GAL) impairs performance on cognitive tasks when administered centrally to rats. GAL transgenic (GAL-tg) mice overexpressing endogenous GAL show deficits on the probe trial of the Morris water maze spatial learning task, on the social transmission of food preference olfactory memory task, and on the trace cued fear conditioning emotional learning and memory task. Knockout mice deficient in the GAL-R1 receptor subtype were normal on most memory tasks, while showing a small deficit in trace cued fear conditioning, suggesting a selective role for the GAL-R1 in aversive memories, and implicating other GAL receptor subtypes in spatial learning and olfactory social memory. The growing body of rodent literature implicating excess GAL in cognitive impairment is relevant to the overexpression of GAL in the basal forebrain during the progression of Alzheimer's disease.
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Affiliation(s)
- Nathan R Rustay
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD 20892, USA.
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Brewer A, Langel U, Robinson JK. Intracerebroventricularly administered galanin does not alter operant reaction time or differentially reinforced high rate schedule operant responding in rats. Neurosci Lett 2004; 369:245-9. [PMID: 15464273 DOI: 10.1016/j.neulet.2004.07.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 07/22/2004] [Accepted: 07/28/2004] [Indexed: 11/25/2022]
Abstract
Galanin (Gal) is a 29/30 amino acid neuroendocrine peptide that impairs learning and memory processes, stimulates feeding, and modulates somatosensory, sex, and stress responses. Anatomical markers for Gal are found throughout the brain, including in the caudate-putamen and substantia nigra motor regions. Many of the behavioral tests that have been used to study the involvement of Gal in complex behavioral processes are motorically demanding, but no research has specifically investigated the involvement of Gal in response initiation or the maintenance of fine motor action. Therefore, the present study examined the effects of intraventricularly administered Gal on two highly sensitive operant tasks designed to detect alteration of these response properties. Response initiation was studied using a light-dark discrimination reaction time task that required a correct response within 2.5s of a spatially and temporally uncertain stimulus onset. The ability to perform high local rates of responding was studied using an operant differential reinforcement of high rate (DRH) of responding task. Gal (10-20 microg, i.c.v.) did not alter reaction time or inter-response time distributions in either task, though did substantially reduce the total number of responses and reinforcers obtained on the DRH schedule. These results are consistent with a Gal-induced reduction of reinforcer efficacy rather than Gal-disruption of response initiation or response patterning.
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Affiliation(s)
- Ariel Brewer
- Department of Psychology, Biopsychology Program Area, Stony Brook University, Stony Brook, NY 11794-2500, USA
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Laplante F, Crawley JN, Quirion R. Selective reduction in ventral hippocampal acetylcholine release in awake galanin-treated rats and galanin-overexpressing transgenic mice. ACTA ACUST UNITED AC 2004; 122:91-8. [PMID: 15380926 DOI: 10.1016/j.regpep.2004.05.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 05/28/2004] [Accepted: 05/28/2004] [Indexed: 11/23/2022]
Abstract
The neuropeptide galanin is an inhibitory modulator of hippocampal acetylcholine (ACh) release and cognitive functions. Anatomical evidence demonstrated some differences between the dorsal and ventral hippocampi notably in the expression of galanin receptor subtypes, and the neuronal population on which galanin-like immunoreactivity is expressed. This is suggestive of a differential role for this peptide in these two areas of the hippocampal formation. Using in vivo microdialysis, we investigated the role of galanin on ACh release in the dorsal and ventral hippocampi. Two models were studied: galanin-administered rats and transgenic mice over-expressing galanin (GAL-tg). In rats, galanin (2.0 and 10.0 microM) infused locally through the dialysis probe induced a significant decrease in ACh release in the ventral hippocampus, confirming previous findings, while no effect was seen in the dorsal hippocampus. Using the no net flux method, a significant reduction in ACh levels was noted only in the ventral hippocampus of GAL-tg compared to wild-type littermates. These results suggest that excess endogenous galanin can suppress basal ACh release, with anatomical specificity, to the ventral hippocampus. These results are of interest in the context of galanin receptor subtypes in the dorsal and ventral hippocampus, and the differential alterations of hippocampal subregions in neurological diseases such as Alzheimer's dementia.
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Affiliation(s)
- François Laplante
- Douglas Hospital Research Centre, Department of Pharmacology/Therapeutics and Department of Psychiatry, McGill University, 6875 Boul. LaSalle Verdun, QC, Canada H4H 1R3
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Naftalin RJ, Cunningham P, Afzal-Ahmed I. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport. Br J Pharmacol 2004; 142:594-608. [PMID: 15148255 PMCID: PMC1574967 DOI: 10.1038/sj.bjp.0705798] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1 Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. 2 The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (P<0.01). Less potent nootropics, D-levetiracetam and D-pyroglutamate, have higher antagonist Ki's against pentobarbital inhibition of glucose transport than more potent L-stereoisomers (P<0.001). 3 Piracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. 4 There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. 5 Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis.
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Affiliation(s)
- Richard J Naftalin
- Physiology Division, Centre for Vascular Biology and Medicine, King's College London, Guy's Campus, New Hunt's House, London SE1 1UL.
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