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Saad K, Abdel-Rahman AA, Al-Atram AA, Abdallah AEM, Elhoufey A, Abdelsalam EMN, Nigm DA, Elshora O, Ahmad AR, El-Tellawy MM, Mahmoud KH. Serum Galanin in Children with Autism Spectrum Disorder. Child Psychiatry Hum Dev 2022; 53:300-306. [PMID: 33534034 DOI: 10.1007/s10578-021-01127-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/15/2021] [Indexed: 02/05/2023]
Abstract
Recent studies have attempted to measure several biomarkers to understand the complex interactions of the anatomic systems that may be involved in autism spectrum disorder (ASD). In CNS, galanin takes part in a variety of pathological and physiological processes. Prior research has indicated it is involved in several neuropsychiatric disorders and has a role in inhibiting the neuronal firing and release of serotonin, norepinephrine, and acetylcholine. To date, serum galanin levels have not been investigated in the context of ASD. This study aimed, therefore, to compare the serum galanin levels of children with ASD and healthy controls and to reveal any association between galanin level and the severity of ASD, as well as other psychological and demographic parameters. Serum galanin levels were measured by radioimmunoassay in 116 children with ASD and 98 healthy children. We observed significantly increased serum concentrations of galanin in children with ASD relative to healthy children. Moreover, children with severe ASD had significantly higher galanin levels than those with less severe disease. We also confirmed significant positive correlations between galanin and psychiatric parameters in children with ASD. For the first time, we suggest a possible correlation between serum galanin and the degree of ASD severity. Increased galanin levels may play a role in the pathogenesis of ASD.
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Affiliation(s)
- Khaled Saad
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, 71516, Egypt.
| | - Ahmed A Abdel-Rahman
- Department of Neuropsychiatry, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Abdulrahman A Al-Atram
- Department of Psychiatry, College of Medicine, Majmaah University, Al Majmaah, Kingdom of Saudi Arabia
| | - Alam-Eldin M Abdallah
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, 71516, Egypt
| | - Amira Elhoufey
- Department of Community Health Nursing, Faculty of Nursing, Assiut University, Assiut, Egypt
- Department of Community Health Nursing, Alddrab University College, Jazan University, Jazan, Kingdom of Saudi Arabia
| | | | - Dalia A Nigm
- Clinical Pathology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Ola Elshora
- Clinical Pathology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Ahmad Roshdy Ahmad
- Department of Pediatrics, College of Medicine, Jouf University, Sakakah, Kingdom of Saudi Arabia
| | - Mohamed M El-Tellawy
- Department of Pediatrics, College of Medicine, Jouf University, Sakakah, Kingdom of Saudi Arabia
| | - Khaled Hashim Mahmoud
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, 71516, Egypt
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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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Messanvi F, Perkins A, du Hoffmann J, Chudasama Y. Fronto-temporal galanin modulates impulse control. Psychopharmacology (Berl) 2020; 237:291-303. [PMID: 31705163 PMCID: PMC7024046 DOI: 10.1007/s00213-019-05365-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022]
Abstract
RATIONALE The neuropeptide galanin has been implicated in a wide range of pathological conditions in which frontal and temporal structures are compromised. It works through three subtypes of G-protein-coupled receptors. One of these, the galanin receptor 1 (Gal-R1) subtype, is densely expressed in the ventral hippocampus (vHC) and ventral prefrontal cortex (vPFC); two brain structures that have similar actions on behavioral control. We hypothesize that Gal-R1 contributes to cognitive-control mechanisms that require hippocampal-prefrontal cortical circuitry. OBJECTIVE To examine the effect of local vHC and vPFC infusions of M617, a Gal-R1 agonist, on inhibitory mechanisms of response control. METHODS Different cohorts of rats were implanted with bilateral guide cannulae targeting the vPFC or the vHC. Following infusion of the Gal-R1 agonist, we examined the animals' behavior using a touchscreen version of the 5-choice reaction time task (5-choice task). RESULTS The Gal-R1 agonist produced opposing behaviors in the vPFC and vHC, leading to disruption of impulse control when infused in the vPFC but high impulse control when infused into the vHC. This contrast between areas was accentuated when we added variability to the timing of the stimulus, which led to long decision times and reduced accuracy in the vPFC group but a general improvement in performance accuracy in the vHC group. CONCLUSIONS These results provide the first evidence of a selective mechanism of Gal-R1-mediated modulation of impulse control in prefrontal-hippocampal circuitry.
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Affiliation(s)
- F Messanvi
- Section on Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD, USA.
| | - A Perkins
- Section on Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD, USA
| | - J du Hoffmann
- Rodent Behavioral Core, National Institute of Mental Health, Bethesda, MD, USA
| | - Y Chudasama
- Section on Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD, USA
- Rodent Behavioral Core, National Institute of Mental Health, Bethesda, MD, USA
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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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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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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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Zhao X, Yun K, Seese RR, Wang Z. Galnon facilitates extinction of morphine-conditioned place preference but also potentiates the consolidation process. PLoS One 2013; 8:e76395. [PMID: 24146862 PMCID: PMC3795750 DOI: 10.1371/journal.pone.0076395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/30/2013] [Indexed: 12/17/2022] Open
Abstract
Learning and memory systems are intimately involved in drug addiction. Previous studies suggest that galanin, a neuropeptide that binds G-protein coupled receptors, plays essential roles in the encoding of memory. In the present study, we tested the function of galnon, a galanin receptor 1 and 2 agonist, in reward-associated memory, using conditioned place preference (CPP), a widely used paradigm in drug-associated memory. Either before or following CPP-inducing morphine administration, galnon was injected at four different time points to test the effects of galanin activation on different reward-associated memory processes: 15 min before CPP training (acquisition), immediately after CPP training (consolidation), 15 min before the post-conditioning test (retrieval), and multiple injection after post-tests (reconsolidation and extinction). Galnon enhanced consolidation and extinction processes of morphine-induced CPP memory, but the compound had no effect on acquisition, retrieval, or reconsolidation processes. Our findings demonstrate that a galanin receptor 1 and 2 agonist, galnon, may be used as a viable compound to treat drug addiction by facilitating memory extinction process.
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Affiliation(s)
- Xiaojie Zhao
- Department of Forensic Science, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi, PR China
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Keming Yun
- School of Forensic Medicine, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Ronald R. Seese
- Department of Anatomy & Neurobiology, University of California Irvine, School of Medicine, Irvine, California, United States of America
| | - Zhenyuan Wang
- Department of Forensic Science, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi, PR China
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Galanin differentially regulates acetylcholine release in ventral and dorsal hippocampus: a microdialysis study in awake rat. Neuroscience 2011; 197:172-80. [DOI: 10.1016/j.neuroscience.2011.09.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 11/21/2022]
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Elliott-Hunt CR, Holmes FE, Hartley DM, Perez S, Mufson EJ, Wynick D. Endogenous galanin protects mouse hippocampal neurons against amyloid toxicity in vitro via activation of galanin receptor-2. J Alzheimers Dis 2011; 25:455-62. [PMID: 21471641 PMCID: PMC3145121 DOI: 10.3233/jad-2011-110011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Expression of the neuropeptide galanin is known to be upregulated in the brain of patients with Alzheimer's disease (AD). We and others have shown that galanin plays a neuroprotective role in a number of excitotoxic injury paradigms, mediated by activation of the second galanin receptor subtype (GAL2). In the present study, we investigated whether galanin/GAL2 plays a similar protective role against amyloid-β(Aβ) toxicity. Here we report that galanin or the GAL2/3-specific peptide agonist Gal2-11, both equally protect primary dispersed mouse wildtype (WT) neonatal hippocampal neurons from 250 nM Aβ1-42 toxicity in a dose dependent manner. The amount of Aβ1-42 induced cell death was significantly greater in mice with loss-of-function mutations in galanin (Gal-KO) or GAL2 (GAL2-MUT) compared to strain-matched WT controls. Conversely, cell death was significantly reduced in galanin over-expressing (Gal-OE) transgenic mice compared to strain-matched WT controls. Exogenous galanin or Gal2-11 rescued the deficits in the Gal-KO but not the GAL2-MUT cultures, confirming that the protective effects of endogenous or exogenous galanin are mediated by activation of GAL2. Despite the high levels of endogenous galanin in the Gal-OE cultures, the addition of exogenous 100 nM or 50 nM galanin or 100 nM Gal2-11 further significantly reduced cell death, implying that GAL2-mediated neuroprotection is not at maximum in the Gal-OE mice. These data further support the hypothesis that galanin over-expression in AD is a neuroprotective response and imply that the development of a drug-like GAL2 agonist might reduce the progression of symptoms in patients with AD.
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Affiliation(s)
- Caroline R. Elliott-Hunt
- Schools of Physiology and Pharmacology and Clinical Sciences, University of Bristol, Bristol, UK
| | - Fiona E. Holmes
- Schools of Physiology and Pharmacology and Clinical Sciences, University of Bristol, Bristol, UK
| | - Dean M. Hartley
- Department of Neurological Sciences, Rush University Medical Center, Chicago University, Chicago, IL, USA
| | - Sylvia Perez
- Department of Neurological Sciences, Rush University Medical Center, Chicago University, Chicago, IL, USA
| | - Elliott J. Mufson
- Department of Neurological Sciences, Rush University Medical Center, Chicago University, Chicago, IL, USA
| | - David Wynick
- Schools of Physiology and Pharmacology and Clinical Sciences, University of Bristol, Bristol, UK
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Bolborea M, Ansel L, Weinert D, Steinlechner S, Pévet P, Klosen P. The bed nucleus of the stria terminalis in the Syrian hamster (Mesocricetus auratus): absence of vasopressin expression in standard and wild-derived hamsters and galanin regulation by seasonal changes in circulating sex steroids. Neuroscience 2009; 165:819-30. [PMID: 19909796 DOI: 10.1016/j.neuroscience.2009.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 11/02/2009] [Accepted: 11/04/2009] [Indexed: 11/26/2022]
Abstract
The bed nucleus of the stria terminalis (BNST) is a nucleus of the forebrain highly sensitive to sex steroids and containing vasopressin neurons implicated in several social- and reproduction-related behaviours such as scent-marking, aggression, pair bonding and parental behaviour. Sexually dimorphic vasopressin expression in BNST neurons has been reported in almost all rodents, with the notable exception of the Syrian hamster. In this species, vasopressin expression is completely absent in the BNST. Because almost all Syrian hamsters used in research are derived from a very small breeding stock captured in 1930, we compared commercially available Syrian hamsters with a recently captured, wild-derived breeding stock. We checked for vasopressin expression using in situ hybridization and immunohistochemistry. Vasopressin expression in BNST neurons was completely absent in both breeding stocks, confirming the absence of BNST vasopressin expression in Mesocricetus auratus and ruling out a breeding artefact. Because vasopressin expression in BNST neurons appears to be strictly dependent on circulating sex steroids, the absence of vasopressin expression in Syrian hamster BNST neurons might be due to an insensitivity of these neurons to sex steroids. BNST vasopressin neurons also express galanin. Although galanin expression in the BNST is not sexually dimorphic in the Syrian hamster, it appears to be regulated by sex steroids. In the Djungarian hamster, photoperiodically driven seasonal variations of circulating sex steroids result in a seasonal rhythm of galanin expression in BNST neurons. We analysed the sex steroid dependence of galanin expression in the Syrian hamster. Castration and short photoperiod-induced sexual quiescence both resulted in downregulation of galanin mRNA in cell bodies (BNST) and immunoreactivity in the fibres (lateral septum). Testosterone supplementation of short photoperiod-adapted animals was able to restore galanin expression. Thus Syrian hamster BNST neurons respond to circulating sex steroids and their seasonal variations as observed in other rodent species.
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Affiliation(s)
- M Bolborea
- Tierärztliche Hochschule, Institut für Zoologie, Bünteweg 17, 30559 Hannover, Germany
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Picciotto MR, Brabant C, Einstein EB, Kamens HM, Neugebauer NM. Effects of galanin on monoaminergic systems and HPA axis: Potential mechanisms underlying the effects of galanin on addiction- and stress-related behaviors. Brain Res 2009; 1314:206-18. [PMID: 19699187 DOI: 10.1016/j.brainres.2009.08.033] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/06/2009] [Accepted: 08/09/2009] [Indexed: 12/20/2022]
Abstract
Like a number of neuropeptides, galanin can alter neural activity in brain areas that are important for both stress-related behaviors and responses to drugs of abuse. Accordingly, drugs that target galanin receptors can alter behavioral responses to drugs of abuse and can modulate stress-related behaviors. Stress and drug-related behaviors are interrelated: stress can promote drug-seeking, and drug exposure and withdrawal can increase activity in brain circuits involved in the stress response. We review here what is known about the ability of galanin and galanin receptors to alter neuronal activity, and we discuss potential mechanisms that may underlie the effects of galanin on behaviors involved in responses to stress and addictive drugs. Understanding the mechanisms underlying galanin's effects on neuronal function in brain regions related to stress and addiction may be useful in developing novel therapeutics for the treatment of stress- and addiction-related disorders.
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Affiliation(s)
- Marina R Picciotto
- Division of Molecular Psychiatry, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, Yale University School of Medicine, New Haven, CT, USA.
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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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13
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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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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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Abstract
Aging is associated with a progressive decline in physical and cognitive functions. The impact of age-dependent endocrine changes regulated by the central nervous system on the dynamics of neuronal behavior, neurodegeneration, cognition, biological rhythms, sexual behavior, and metabolism are reviewed. We also briefly review how functional deficits associated with increases in glucocorticoids and cytokines and declining production of sex steroids, GH, and IGF are likely exacerbated by age-dependent molecular misreading and alterations in components of signal transduction pathways and transcription factors.
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Affiliation(s)
- Roy G Smith
- Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, M320, Houston, TX 77030, USA.
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Kinney JW, Starosta G, Crawley JN. Central galanin administration blocks consolidation of spatial learning. Neurobiol Learn Mem 2003; 80:42-54. [PMID: 12737933 DOI: 10.1016/s1074-7427(03)00023-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Galanin is a neuropeptide that inhibits the evoked release of several neurotransmitters, inhibits the activation of intracellular second messengers, and produces deficits in a variety of rodent learning and memory tasks. To evaluate the actions of galanin on encoding, consolidation, and storage/retrieval, galanin was acutely administered to Sprague-Dawley rats at time points before and after training trials in the Morris water maze. Intraventricular administration of galanin up to 3h after subjects had completed daily training trials in the Morris water task impaired performance on the probe trial, indicating that galanin-blocked consolidation. Pretreatment with an adenylate cyclase activator, forskolin, prevented the deficits in distal cue learning produced by galanin. Di-deoxyforskolin, an inactive analog of forskolin, had no effect. These results provide the first evidence that galanin interferes with long-term memory consolidation processes. A potential mechanism by which galanin produces this impairment may involve the inhibition of adenylate cyclase activity, leading to inhibition of downstream molecular events that are necessary for consolidation of long-term memory.
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Affiliation(s)
- Jefferson W Kinney
- Section on Behavioral Genomics, National Institute of Mental Health, Galanin Inhibits Consolidation, Building 10 Room 4011, Bethesda, MD 20892-1375, USA.
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18
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Yoshitake T, Reenilä I, Ogren SO, Hökfelt T, Kehr J. Galanin attenuates basal and antidepressant drug-induced increase of extracellular serotonin and noradrenaline levels in the rat hippocampus. Neurosci Lett 2003; 339:239-42. [PMID: 12633897 DOI: 10.1016/s0304-3940(03)00020-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Galanin is co-localized with classical neurotransmitters, such as acetylcholine, serotonin (5-HT) and noradrenaline (NA) in neurons or in brain regions implicated in cognitive and affective behaviour. In the present study, the effects of galanin on extracellular 5-HT and NA levels in the rat hippocampus were measured by in vivo microdialysis under basal conditions and following systemic administration of antidepressant drugs. Galanin (1.5 nmol i.c.v.) reduced basal 5-HT and NA levels to 65% and 86% of controls, respectively. Galanin (0.5 and 1.5 nmol i.c.v.) dose-dependently attenuated the elevation of 5-HT concentrations induced by imipramine and citalopram (10 mg/kg i.p., each) from 350% to 312% and from 230% to 160%, respectively. Galanin at 1.5 nmol transiently attenuated the effect of desipramine-induced (10 mg/kg i.p.) increase in extracellular NA levels from a maximal increase of 389-296% of the predrug levels. It is concluded that intraventricularly administered galanin attenuated both basal 5-HT and NA release and antidepressant drug-induced accumulation of extracellular 5-HT and NA levels most likely via a predominant inhibitory action on serotonergic and noradrenergic neurons in the raphe and locus coeruleus, respectively. These results further emphasize a possible role of galanin in regulation of 5-HT and NA neurotransmission in depressive states and during the course of antidepressant therapy.
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Affiliation(s)
- Takashi Yoshitake
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
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19
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Larm JA, Shen PJ, Gundlach AL. Differential galanin receptor-1 and galanin expression by 5-HT neurons in dorsal raphé nucleus of rat and mouse: evidence for species-dependent modulation of serotonin transmission. Eur J Neurosci 2003; 17:481-93. [PMID: 12581166 DOI: 10.1046/j.1460-9568.2003.02471.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Galanin and galanin receptors are widely expressed by neurons in rat brain that either synthesize/release and/or are responsive to, classical transmitters such as gamma-aminobutyric acid, acetylcholine, noradrenaline, histamine, dopamine and serotonin (5-hydroxytryptamine, 5-HT). The dorsal raphé nucleus (DRN) contains approximately 50% of the 5-HT neurons in the rat brain and a high percentage of these cells coexpress galanin and are responsive to exogenous galanin in vitro. However, the precise identity of the galanin receptor(s) present on these 5-HT neurons has not been previously established. Thus, the current study used a polyclonal antibody for the galanin receptor-1 (GalR1) to examine the possible expression of this receptor within the DRN of the rat and for comparative purposes also in the mouse. In the rat, intense GalR1-immunoreactivity (IR) was detected in a substantial population of 5-HT-immunoreactive neurons in the DRN, with prominent receptor immunostaining associated with soma and proximal dendrites. GalR1-IR was also observed in many cells within the adjacent median raphé nucleus. In mouse DRN, neurons exhibited similar levels and distribution of 5-HT-IR to that in the rat, but GalR1-IR was undetectable. Consistent with this, galanin and GalR1 mRNA were also undetectable in mouse DRN by in situ hybridization histochemistry, despite the detection of GalR1 mRNA (and GalR1-IR) in adjacent cells in the periaqueductal grey and other midbrain areas. 5-HT neuron activity in the DRN is primarily regulated via 5-HT1A autoreceptors, via inhibition of adenylate cyclase and activation of inward-rectifying K+ channels. Notably, the GalR1 receptor subtype signals via identical mechanisms and our findings establish that galanin modulates 5-HT neuron activity in the DRN of the rat via GalR1 (auto)receptors. However, these studies also identify important species differences in the relationship between midbrain galanin and 5-HT systems, which should prompt further investigations in relation to comparative human neurochemistry and which have implications for studies of animal models of relevant neurological conditions such as stress, anxiety and depression.
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Affiliation(s)
- Jari A Larm
- Howard Florey Institute of Experimental Physiology and Medicine, Austin & Repatriation Medical Centre, The University of Melbourne, Victoria, Australia
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Massey PV, Warburton EC, Wynick D, Brown MW, Bashir ZI. Galanin regulates spatial memory but not visual recognition memory or synaptic plasticity in perirhinal cortex. Neuropharmacology 2003; 44:40-8. [PMID: 12559120 DOI: 10.1016/s0028-3908(02)00297-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It has previously been shown that the neuropeptide galanin plays a role in the age-dependent regulation of hippocampal synaptic plasticity and spatial memory. Here, we further extend these studies by demonstrating that galanin knockout mice also have deficits in an object-in-place spatial memory task. In contrast however, there is no deficit in single item object recognition memory, a memory that depends on perirhinal cortex. Furthermore, in perirhinal cortex slices there are no differences in activity-dependent long-term potentiation or depotentiation, nor in muscarinic receptor-dependent long-term depression between galanin knockout mice and wild-type litter-mates. Therefore, these results suggest that galanin has a differential role in hippocampal-dependent and perirhinal cortex-dependent memory.
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Affiliation(s)
- P V Massey
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, BS8 1TD, Bristol, UK.
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21
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Abstract
The neuropeptide galanin has a widespread but no means ubiquitous expression pattern in the nervous and endocrine systems. Profound changes in the levels and distribution of the peptide occur in a range of path-physiological situations including nerve injury or damage and alterations in the circulating levels of a number of hormones. There is now a substantial body of work to indicate that galanin plays an important biological role as a regulator of neurotransmitter and hormone release in the adult. The recent generation of mice carrying a loss-of-function mutation within the galanin gene has allowed us new insights into the physiological actions of galanin. In this manuscript we detail three sets of data relating to the major phenotypic effects thus far delineated, putting them in the context of existing published data. These studies demonstrate that galanin acts as a developmental and trophic factor to subsets of neurons in the nervous and neuroendocrine systems.
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Affiliation(s)
- D Wynick
- University Research Centre for Neuroendocrinology, Bristol University, Marlborough Street, Bristol, BS2 8HW
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22
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Jhamandas JH, Harris KH, MacTavish D, Jassar BS. Novel excitatory actions of galanin on rat cholinergic basal forebrain neurons: implications for its role in Alzheimer's disease. J Neurophysiol 2002; 87:696-704. [PMID: 11826038 DOI: 10.1152/jn.00416.2001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Galanin, a 29-amino-acid neuropeptide, is generally viewed as an inhibitory neuromodulator in a variety of central systems. Galanin expression is upregulated in the cholinergic basal forebrain nuclei in Alzheimer's disease (AD) and is postulated to play an important role in memory and cognitive function. In this study, application of galanin to acutely dissociated rat neurons from the basal forebrain nucleus diagonal band of Broca (DBB), caused a decrease in whole cell voltage-activated currents in a majority of cells. Galanin reduces a suite of potassium currents, including calcium-activated potassium (I(C)), the delayed rectifier (I(K)), and transient outward potassium (I(A)) conductances, but not calcium or sodium currents. Under current-clamp conditions, application of galanin evoked an increase in excitability and a loss of accommodation in cholinergic DBB neurons. Using single-cell RT-PCR technique, we determined that galanin actions were specific to cholinergic, but not GABAergic DBB neurons The notion that galanin plays a deleterious role in AD is based, in part, on galanin hyperinnervation of cholinergic cells in the basal forebrain of AD patients, its ability to depress acetylcholine release and its inhibitory actions at other CNS sites. However, our results suggest that by virtue of its excitatory actions on cholinergic neurons, galanin may in fact play a compensatory role by augmenting the release of acetylcholine from remaining cholinergic basal forebrain neurons. This action might serve to delay the progression of AD pathology linked to a reduction in central cholinergic tone.
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Affiliation(s)
- Jack H Jhamandas
- Division of Neurology, Department of Medicine, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, Alberta T6G 2S2, Canada.
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Abstract
Galanin is a neuroendocrine peptide involved in the regulation of feeding, pain, sexual behavior, learning, and memory. The recent discovery, that galanin antagonized excitatory glutamatergic neurotransmission in the hippocampus, provided a rationale for its possible antiepileptic effects. Here we summarize the data on the effects of galanin on seizure activity in several animal models of epilepsy. Pharmacological and molecular biological evidence suggest potent anticonvulsant effects of galanin. Exogenous administration of galanin receptor agonists attenuated seizures, whereas application of galanin receptor antagonists potentiated seizure expression. Genetically engineered mice, with either deletion or overexpression of galanin gene, showed altered resistance to seizures, which was in direct correlation with galanin gene expression. Possible mechanisms of the anticonvulsant action of galanin include its effects on synaptic potentiation in hippocampal circuits and inhibition of the release of the excitatory neurotransmitter glutamate from principal hippocampal neurons.
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Affiliation(s)
- A Mazarati
- Department of Neurology, UCLA School of Medicine and West LA VA Medical Center, Los Angeles, CA 90073, USA.
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Adeghate E, Ponery AS. Large reduction in the number of galanin-immunoreactive cells in pancreatic islets of diabetic rats. J Neuroendocrinol 2001; 13:706-10. [PMID: 11489087 DOI: 10.1046/j.1365-2826.2001.00682.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although galanin has been shown to be present in pancreatic islet cells, there is no literature available on the pattern of distribution and the effect of galanin in the pancreas of diabetic animals or human models. The aim of this study was to examine whether galanin immunoreactivity changes after the onset of diabetes mellitus in the rat model. The present study used immunohistochemical techniques to examine the pattern of distribution of galanin-like immunoreactive cells in the pancreas of rats with streptozotocin-induced diabetes. The effect of galanin on insulin secretion from intact rat pancreatic tissue fragments was also investigated using a radioimmunoassay technique. Numerous galanin-like immunoreactive cells were observed in both the peripheral and central regions of the islet of Langerhans of normal rat pancreas. By contrast, the islets of diabetic rat pancreas contained significantly (P < 0.0001) fewer galanin-like immunoreactive cells than nondiabetic rats. Galanin was colocalized with insulin in the islets of normal and diabetic rats. Galanin had an inhibitory effect on insulin secretion from the isolated pancreatic tissue fragments of normal and diabetic rats at all concentrations (10(-12) to 10(-6) M) employed. Galanin at 10(-9) M caused a significant (P < 0.02) decrease in insulin secretion from normal rat pancreatic tissue fragments compared to basal. These observations indicate that galanin may play a significant role in the regulation of insulin secretion.
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Affiliation(s)
- E Adeghate
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
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Schött PA, Hökfelt T, Ogren SO. Galanin and spatial learning in the rat. Evidence for a differential role for galanin in subregions of the hippocampal formation. Neuropharmacology 2000; 39:1386-403. [PMID: 10818255 DOI: 10.1016/s0028-3908(00)00053-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Anatomical, neurochemical and behavioural evidence support a role for galanin in hippocampally mediated functions such as spatial learning and memory. To obtain more precise information on this role, galanin (3 nmol/rat) was infused via bilateral chronic cannulae into different areas of the hippocampal formation which are characterized by different galanin receptor subtypes and also by different galanin innervation patterns. The effects of infused galanin on spatial learning were examined in the Morris swim maze. Infusions of galanin into both the dorsal and ventral dentate gyrus, which mainly contain GAL-R2 receptor mRNA and a high degree of galanin-noradrenaline coexistence, significantly retarded spatial acquisition without affecting swim speed or performance in the visible platform test. This spatial learning deficit was fully blocked by pretreatment with the non-selective galanin antagonist M35. Analysis of retention performance suggested that the major effect of intrahippocampal galanin is mediated via a specific disruption of acquisition mechanisms of importance for performance in the probe trial. Galanin infused into the ventral CA1 (a mainly GAL-R1 receptor mRNA expressing region) or into anterior, ventral CA3 regions did not produce any deficits in spatial learning compared to control animals. These results suggest that galanin mediates its action on spatial learning mainly through the GAL-R2 receptor subtype in areas where most of the galanin is present in noradrenergic terminals. A possible role for the GAL-R1 receptor subtype in cognition in the dorsal and ventral hippocampus remains to be defined. The results suggest a differential functional role for galanin and galanin receptor subtypes within subregions of the hippocampal formation.
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Affiliation(s)
- P A Schött
- Department of Neuroscience, Karolinska Institutet, SE-171 77, Stockholm, Sweden
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