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Gimeno-Ferrer F, Eitner A, Bauer R, Lehmenkühler A, Schaible HG, Richter F. Cortical spreading depolarization is a potential target for rat brain excitability modulation by Galanin. Exp Neurol 2023; 370:114569. [PMID: 37827229 DOI: 10.1016/j.expneurol.2023.114569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 08/24/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
The inhibitory neuropeptide Galanin (Gal) has been shown to mediate anticonvulsion and neuroprotection. Here we investigated whether Gal affects cortical spreading depolarization (CSD). CSD is considered the pathophysiological neuronal mechanism of migraine aura, and a neuronal mechanism aggravating brain damage upon afflictions of the brain. Immunohistochemistry localized Gal and the Gal receptors 1-3 (GalR1-3) in native rat cortex and evaluated microglial morphology after exposure to Gal. In anesthetized rats, Gal was applied alone and together with the GalR antagonists M40, M871, or SNAP 37889 locally to the exposed cortex. The spontaneous electrocorticogram and CSDs evoked by remote KCl pressure microinjection were measured. In rat cortex, Gal was present in all neurons of all cortical layers, but not in astrocytes, microglia and vessels. GalR2 and GalR3 were expressed throughout all neurons, whereas GalR1 was preponderantly located at neurons in layers IV and V, but only in about half of the neurons. In susceptible rats, topical application of Gal on cortex decreased CSD amplitude, slowed CSD propagation velocity, and increased the threshold for KCl to ignite CSD. In some rats, washout of previously applied Gal induced periods of epileptiform patterns in the electrocorticogram. Blockade of GalR2 by M871 robustly prevented all Gal effects on CSD, whereas blockade of GalR1 or GalR3 was less effective. Although microglia did not express GalRs, topical application of Gal changed microglial morphology indicating microglial activation. This effect of Gal on microglia was prevented by blocking neuronal GalR2. In conclusion, Gal has the potential to ameliorate CSD thus reducing pathophysiological neuronal events caused by or associated with CSD.
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Affiliation(s)
- Fátima Gimeno-Ferrer
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany
| | - Annett Eitner
- Department of Trauma, Hand and Reconstructive Surgery, Experimental Trauma Surgery, Jena University Hospital, Jena D-07740, Germany
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, CMB-Center for Molecular Biomedicine, Jena University Hospital, Jena D-07740, Germany
| | | | - Hans-Georg Schaible
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany
| | - Frank Richter
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany.
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2
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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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3
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Devilbiss DM. Consequences of tuning network function by tonic and phasic locus coeruleus output and stress: Regulating detection and discrimination of peripheral stimuli. Brain Res 2018; 1709:16-27. [PMID: 29908165 DOI: 10.1016/j.brainres.2018.06.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/23/2018] [Accepted: 06/12/2018] [Indexed: 12/15/2022]
Abstract
Flexible and adaptive behaviors have evolved with increasing complexity and numbers of neuromodulator systems. The neuromodulatory locus coeruleus-norepinephrine (LC-NE) system is central to regulating cognitive function in a behaviorally-relevant and arousal-dependent manner. Through its nearly ubiquitous efferent projections, the LC-NE system acts to modulate neuron function on a cell-by-cell basis and exert a spectrum of actions across different brain regions to optimize target circuit function. As LC neuron activity, NE signaling, and arousal level increases, cognitive performance improves over an inverted-U shaped curve. Additionally, LC neurons burst phasically in relation to novel or salient sensory stimuli and top-down decision- or response-related processes. Together, the variety of LC activity patterns and complex actions of the LC-NE system indicate that the LC-NE system may dynamically regulate the function of target neural circuits. The manner in which neural networks encode, represent, and perform neurocomputations continue to be revealed. This has improved our ability to understand the optimization of neural circuits by NE and generation of flexible and adaptive goal-directed behaviors. In this review, the rat vibrissa somatosensory system is explored as a model neural circuit to bridge known modulatory actions of NE and changes in cognitive function. It is argued that fluid transitions between neural computational states reflect the ability of this sensory system to shift between two principal functions: detection of novel or salient sensory information and detailed descriptions of sensory information. Such flexibility in circuit function is likely critical for producing context-appropriate sensory signal processing. Nonetheless, many challenges remain including providing a causal link between NE mediated changes in sensory neural coding and perceptual changes, as well as extending these principles to higher cognitive functions including behavioral flexibility and decision making.
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Affiliation(s)
- David M Devilbiss
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, United States.
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4
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Galanin subtype 1 and subtype 2 receptors mediate opposite anxiety-like effects in the rat dorsal raphe nucleus. Behav Brain Res 2016; 314:125-33. [DOI: 10.1016/j.bbr.2016.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/01/2016] [Accepted: 08/03/2016] [Indexed: 01/09/2023]
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Petschner P, Juhasz G, Tamasi V, Adori C, Tothfalusi L, Hökfelt T, Bagdy G. Chronic venlafaxine treatment fails to alter the levels of galanin system transcripts in normal rats. Neuropeptides 2016; 57:65-70. [PMID: 26891823 DOI: 10.1016/j.npep.2016.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/22/2016] [Accepted: 01/31/2016] [Indexed: 11/16/2022]
Abstract
It is widely accepted that efficacy and speed of current antidepressants' therapeutic effect are far from optimal. Thus, there is a need for the development of antidepressants with new mechanisms of action. The neuropeptide galanin and its receptors (GalR1, GalR2 and GalR3) are among the promising targets. However, it is not clear whether or not the galanin system is involved in the antidepressant effect exerted by the currently much used inhibitors of the reuptake of serotonin and/or noradrenaline. To answer this question we administered the selective serotonin and noradrenaline reuptake inhibitor (SNRI) venlafaxine (40mg/kg/day via osmotic minipumps) to normal rats and examined the levels of the transcripts for galanin and GalR1-3 after a 3-week venlafaxine treatment in the dorsal raphe, hippocampus and frontal cortex. These areas are known to be involved in the effects of antidepressants and in depression itself. Venlafaxine failed to alter the expression of any of the galanin system genes in these areas. Our results show that one of the most efficient, currently used SNRIs does not alter transcript levels of galanin or its three receptors in normal rats. These findings suggest that the pro- and antidepressive-like effects of galanin reported in animal experiments may employ a novel mechanism(s).
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Affiliation(s)
- Peter Petschner
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Gabriella Juhasz
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE-NAP B Genetic Brain Imaging Migraine Research Group, Hungarian Academy of Sciences, Semmelweis University, Hungary
| | - Viola Tamasi
- Department of Genetics-, Cell and Immunobiology, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Csaba Adori
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Laszlo Tothfalusi
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Tomas Hökfelt
- Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary.
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6
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Kawa L, Barde S, Arborelius UP, Theodorsson E, Agoston D, Risling M, Hökfelt T. Expression of galanin and its receptors are perturbed in a rodent model of mild, blast-induced traumatic brain injury. Exp Neurol 2016; 279:159-167. [PMID: 26928087 DOI: 10.1016/j.expneurol.2016.02.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 02/22/2016] [Accepted: 02/24/2016] [Indexed: 01/05/2023]
Abstract
The symptomatology, mood and cognitive disturbances seen in post-traumatic stress disorder (PTSD) and mild blast-induced traumatic brain injury (mbTBI) overlap considerably. However the pathological mechanisms underlying the two conditions are currently unknown. The neuropeptide galanin has been suggested to play a role in the development of stress and mood disorders. Here we applied bio- and histochemical methods with the aim to elucidate the nature of any changes in the expression of galanin and its receptors in a rodent model of mbTBI. In situ hybridization and quantitative polymerase chain reaction studies revealed significant, injury-induced changes, in some cases lasting at least for one week, in the mRNA levels of galanin and/or its three receptors, galanin receptor 1-3 (GalR1-3). Such changes were seen in several forebrain regions, and the locus coeruleus. In the ventral periaqueductal gray GalR1 mRNA levels were increased, while GalR2 were decreased. Analysis of galanin peptide levels using radioimmunoassay demonstrated an increase in several brain regions including the locus coeruleus, dorsal hippocampal formation and amygdala. These findings suggest a role for the galanin system in the endogenous response to mbTBI, and that pharmacological studies of the effects of activation or inhibition of different galanin receptors in combination with functional assays of behavioral recovery may reveal promising targets for new therapeutic strategies in mbTBI.
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Affiliation(s)
- Lizan Kawa
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden.
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
| | - Ulf P Arborelius
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
| | - Denes Agoston
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden; Department of Anatomy, Physiology and Genetics, The Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, United States
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden.
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
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Holloway BB, Viar KE, Stornetta RL, Guyenet PG. The retrotrapezoid nucleus stimulates breathing by releasing glutamate in adult conscious mice. Eur J Neurosci 2015; 42:2271-82. [PMID: 26096172 DOI: 10.1111/ejn.12996] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/10/2015] [Accepted: 06/17/2015] [Indexed: 11/30/2022]
Abstract
The retrotrapezoid nucleus (RTN) is a bilateral cluster of neurons located at the ventral surface of the brainstem below the facial nucleus. The RTN is activated by hypercapnia and stabilises arterial Pco2 by adjusting lung ventilation in a feedback manner. RTN neurons contain vesicular glutamate transporter-2 (Vglut2) transcripts (Slc17a6), and their synaptic boutons are Vglut2-immunoreactive. Here, we used optogenetics to test whether the RTN increases ventilation in conscious adult mice by releasing glutamate. Neurons located below the facial motor nucleus were transduced unilaterally to express channelrhodopsin-2 (ChR2)-enhanced yellow fluorescent protein, with lentiviral vectors that employ the Phox2b-activated artificial promoter PRSx8. The targeted population consisted of two types of Phox2b-expressing neuron: non-catecholaminergic neurons (putative RTN chemoreceptors) and catecholaminergic (C1) neurons. Opto-activation of a mix of ChR2-expressing RTN and C1 neurons produced a powerful stimulus frequency-dependent (5-15 Hz) stimulation of breathing in control conscious mice. Respiratory stimulation was comparable in mice in which dopamine-β-hydroxylase (DβH)-positive neurons no longer expressed Vglut2 (DβH(C) (re/0);;Vglut2(fl/fl)). In a third group of mice, i.e. DβH(+/+);;Vglut2(fl/fl) mice, we injected a mixture of PRSx8-Cre lentiviral vector and Cre-dependent ChR2 adeno-associated virus 2 unilaterally into the RTN; this procedure deleted Vglut2 from ChR2-expressing neurons regardless of whether or not they were catecholaminergic. The ventilatory response elicited by photostimulation of ChR2-positive neurons was almost completely absent in these mice. Resting ventilatory parameters were identical in the three groups of mice, and their brains contained similar numbers of ChR2-positive catecholaminergic and non-catecholaminergic neurons. From these results, we conclude that RTN neurons increase breathing in conscious adult mice by releasing glutamate.
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Affiliation(s)
- Benjamin B Holloway
- Department of Pharmacology, University of Virginia Health System, P.O. Box 800735, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908-0735, USA
| | - Kenneth E Viar
- Department of Pharmacology, University of Virginia Health System, P.O. Box 800735, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908-0735, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia Health System, P.O. Box 800735, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908-0735, USA
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia Health System, P.O. Box 800735, 1340 Jefferson Park Avenue, Charlottesville, VA, 22908-0735, USA
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8
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Saar I, Runesson J, Järv J, Kurrikoff K, Langel Ü. Novel Galanin Receptor Subtype Specific Ligand in Depression Like Behavior. Neurochem Res 2012. [DOI: 10.1007/s11064-012-0933-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Corticotropin-releasing factor acting at the locus coeruleus disrupts thalamic and cortical sensory-evoked responses. Neuropsychopharmacology 2012; 37:2020-30. [PMID: 22510725 PMCID: PMC3398725 DOI: 10.1038/npp.2012.50] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Stress and stress-related psychiatric disorders, including post-traumatic stress disorder, are associated with disruptions in sensory information processing. The neuropeptide, corticotropin-releasing factor (CRF), coordinates the physiological and behavioral responses to stress, in part, by activating the locus coeruleus-norepinephrine (LC-NE) projection system. Although the LC-NE system is an important modulator of sensory information processing, to date, the consequences of CRF activation of this system on sensory signal processing are poorly understood. The current study examined the dose-dependent actions of CRF at the LC on spontaneous and sensory-evoked discharge of neurons within the thalamus and cortex of the vibrissa somatosensory system in the awake, freely moving rat. Peri-LC infusions of CRF resulted in a dose-dependent suppression of sensory-evoked discharge in ventral posterior medial thalamic and barrel field cortical neurons. A concurrent increase in spontaneous activity was observed. This latter action is generally not found with iontophoretic application of NE to target neurons or stimulation of the LC-NE pathway. Net decreases in signal-to-noise of sensory-evoked responses within both regions suggest that under conditions associated with CRF release at the LC, including stress, the transfer of afferent information within sensory systems is impaired. Acutely, a suppression of certain types of sensory information may represent an adaptive response to an immediate unexpected stressor. Persistence of such effects could contribute to abnormalities of information processing seen in sensorimotor gating associated with stress and stress-related psychopathology.
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Le Maître TW, Xia S, Le Maitre E, Dun XP, Lu J, Theodorsson E, Ogren SO, Hökfelt T, Xu ZQD. Galanin receptor 2 overexpressing mice display an antidepressive-like phenotype: possible involvement of the subiculum. Neuroscience 2011; 190:270-88. [PMID: 21672612 DOI: 10.1016/j.neuroscience.2011.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 04/21/2011] [Accepted: 05/04/2011] [Indexed: 01/13/2023]
Abstract
The behavioral phenotype of a transgenic mouse overexpressing a galanin receptor 2 (GalR2)-enhanced, green fluorescent protein (EGFP)-construct under the platelet-derived growth factor-B promoter, and of controls, was assessed in various behavioral tests, such as the Porsolt forced swim test, as well as the open field, elevated plus maze and passive avoidance tests. In addition, the distribution of GalR2-EGFP expressing cell bodies and processes was studied in the brain of these mice using histochemical methods. Three age groups of the transgenic mice demonstrated decreased levels of immobility in the forced swim test, indicative of antidepressive-like behavior and/or increased stress resistance. Anxiety-like behaviors, measured in two different tests, did not differ between the GalR2-overexpressing and the wild-type mice, nor did motor activity levels, emotional learning or memory behaviors. High levels of GalR2 mRNA and protein expression were observed in the presubiculum, subiculum, cingulate cortex, retrosplenial granular and agranular cortices, subregions of prefrontal cortex, and the olfactory bulb, regions which are directly or indirectly implicated in depression-like behavior. These results may contribute to the understanding of the pathophysiology of major depressive disorder and the role of GalR2 in the regulation of mood, and suggest a potential therapeutic effect by targeting the GalR2 for treatment of depressive disorders.
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Affiliation(s)
- T Wardi Le Maître
- Department of Neuroscience, Karolinska Institutet, Retzius Väg 8, S-17177 Stockholm, Sweden.
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Devilbiss DM, Waterhouse BD. Phasic and tonic patterns of locus coeruleus output differentially modulate sensory network function in the awake rat. J Neurophysiol 2010; 105:69-87. [PMID: 20980542 DOI: 10.1152/jn.00445.2010] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons of the nucleus locus coeruleus (LC) discharge with phasic bursts of activity superimposed on highly regular tonic discharge rates. Phasic bursts are elicited by bottom-up input mechanisms involving novel/salient sensory stimuli and top-down decision making processes; whereas tonic rates largely fluctuate according to arousal levels and behavioral states. Although it is generally believed that these two modes of activity differentially modulate information processing in LC targets, the unique role of phasic versus tonic LC output on signal processing in cells, circuits, and neural networks of waking animals is not well understood. In the current study, simultaneous recordings of individual neurons within ventral posterior medial thalamus and barrel field cortex of conscious rats provided evidence that each mode of LC output produces a unique modulatory impact on single neuron responsiveness to sensory-driven synaptic input and representations of sensory information across ensembles of simultaneously recorded cells. Each mode of LC activation specifically modulated the relationship between sensory-stimulus intensity and the subsequent responses of individual neurons and neural ensembles. Overall these results indicate that phasic versus tonic modes of LC discharge exert fundamentally different modulatory effects on target neuronal circuits within the rodent trigeminal somatosensory system. As such, each mode of LC output may differentially influence signal processing as a means of optimizing behaviorally relevant neural computations within this sensory network. Likely the ability of the LC system to differentially regulate neural responses and local circuit operations according to behavioral demands extends to other brain regions including those involved in higher cognitive functions.
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Affiliation(s)
- David M Devilbiss
- Department of Psychology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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12
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Izdebska K, Ciosek J. Galanin influences on vasopressin and oxytocin release: in vitro studies. Neuropeptides 2010; 44:341-8. [PMID: 20466422 DOI: 10.1016/j.npep.2010.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 03/17/2010] [Accepted: 04/17/2010] [Indexed: 10/19/2022]
Abstract
Galanin (Gal) acts in the central nervous system as the neuromodulator of the hypothalamo-neurohypophysial system function. Present investigations in vitro were undertaken to study the influence of Gal, added to the incubative media at the concentrations of 10(-10), 10(-9), 10(-8) or 10(-7) M, on AVP and OT release from isolated rat hypothalamus (Hth), neurohypophysis (NH) and hypothalamo-neurohypophysial system (Hth-NH). The present results showed that Gal at the concentrations of 10(-10), 10(-9) and 10(-8) M inhibited basal AVP secretion from the all incubated tissues as well as OT release from the NH and Hth-NH explant. On the contrary, 10(-10) M Gal was the reason of intensified basal hypothalamic OT secretion. The presence of Gal at the concentrations of 10(-10) and 10(-8) M in the incubative media enriched in potassium ions excess was the cause of diminished AVP release from the NH and from the Hth-NH explant, respectively. Any effect of Gal on AVP release from the Hth has been observed. All the concentrations of Gal did not exert any effect on OT release from the NH as well as Hth-NH explants. However, the K(+)-evoked OT release from the Hth was distinctly intensified under influence of 10(-10)M as well as 10(-8) M Gal. It may be concluded that: * Gal modifies AVP and OT release in vitro at every level of Hth-NH system. * Gal has been supposed to perform the role of central inhibitory neuromodulator for AVP release from the Hth-NH system. * Gal exerts inhibitory effect on OT release in vitro from NH as well intact Hth-NH system but stimulatory influence on OT secretion at the level of Hth.
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Affiliation(s)
- K Izdebska
- Department of Neuropeptides Research, Medical University of Lodz, Lodz, Poland
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13
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Lanni C, Govoni S, Lucchelli A, Boselli C. Depression and antidepressants: molecular and cellular aspects. Cell Mol Life Sci 2009; 66:2985-3008. [PMID: 19521663 PMCID: PMC11115917 DOI: 10.1007/s00018-009-0055-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 04/28/2009] [Accepted: 05/20/2009] [Indexed: 01/05/2023]
Abstract
Clinical depression is viewed as a physical and psychic disease process having a neuropathological basis, although a clear understanding of its ethiopathology is still missing. The observation that depressive symptoms are influenced by pharmacological manipulation of monoamines led to the hypothesis that depression results from reduced availability or functional deficiency of monoaminergic transmitters in some cerebral regions. However, there are limitations to current monoamine theories related to mood disorders. Recently, a growing body of experimental data has showed that other classes of endogenous compounds, such as neuropeptides and amino acids, may play a significant role in the pathophysiology of affective disorders. With the development of neuroscience, neuronal networks and intracellular pathways have been identified and characterized, describing the existence of the interaction between monoamines and receptors in turn able to modulate the expression of intracellular proteins and neurotrophic factors, suggesting that depression/antidepressants may be intermingled with neurogenesis/neurodegenerative processes.
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Affiliation(s)
- Cristina Lanni
- Department of Experimental and Applied Pharmacology, Centre of Excellence in Applied Biology, University of Pavia, Viale Taramelli 14, 27100 Pavia, Italy
| | - Stefano Govoni
- Department of Experimental and Applied Pharmacology, Centre of Excellence in Applied Biology, University of Pavia, Viale Taramelli 14, 27100 Pavia, Italy
| | - Adele Lucchelli
- Department of Experimental and Applied Pharmacology, Centre of Excellence in Applied Biology, University of Pavia, Viale Taramelli 14, 27100 Pavia, Italy
| | - Cinzia Boselli
- Department of Experimental and Applied Pharmacology, Centre of Excellence in Applied Biology, University of Pavia, Viale Taramelli 14, 27100 Pavia, Italy
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McCown TJ. Adeno-associated virus vector-mediated expression and constitutive secretion of galanin suppresses limbic seizure activity. Neurotherapeutics 2009; 6:307-11. [PMID: 19332324 PMCID: PMC3552295 DOI: 10.1016/j.nurt.2009.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 01/13/2009] [Indexed: 11/16/2022] Open
Abstract
Theoretically, gene therapy techniques offer an attractive alternative treatment option for intractable, focal epilepsies. Although logical gene therapy targets include excitatory and inhibitory receptors, variable viral vector tropism interjects an uncertainty as to the direction of change, seizure suppression, or seizure sensitization. To circumvent this therapeutic liability, adeno-associated virus (AAV) vectors have been constructed where the gene product is constitutively secreted from the transduced cell. Using AAV vectors, the fibronectin secretory signal sequence (FIB) was placed in front of the coding sequence for green fluorescent protein or the active portion of the neuroactive peptide galanin (GAL). Subsequent studies showed that these vectors supported expression and constitutive secretion of these gene products from transfected cells in vitro. More importantly, upon transduction in vivo, AAV-FIB-GAL vectors significantly attenuated focal seizure sensitivity, and this seizure attenuation could be controlled in vivo by using a tetracycline-regulated promoter. The expression and constitutive secretion of green fluorescent protein, or the expression of GAL alone, exerted no effect on focal seizure sensitivity. Moreover, unilateral infusion of the AAV-FIB-GAL vectors into the hippocampus prevented kainic acid-induced hilar cell death. With regard to limbic seizures, bilateral infusion of AAV-FIB-GAL vectors into the piriform cortex prevented both behavioral and localized electrographic seizure activity after the peripheral administration of kainic acid. Also, when rats were electrically kindled to class V seizure activity, subsequent infusion of AAV-FIB-GAL proved capable of significantly elevating the seizure initiation threshold. Thus, these studies clearly demonstrate the anti-seizure effectiveness of AAV vector-mediated expression and constitutive secretion of galanin.
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Affiliation(s)
- Thomas J McCown
- UNC Gene Therapy Center, Department of Psychiatry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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McCown TJ. Adeno-associated Virus-Mediated Expression and Constitutive Secretion of Galanin Suppresses Limbic Seizure Activity in Vivo. Mol Ther 2006; 14:63-8. [PMID: 16730475 DOI: 10.1016/j.ymthe.2006.04.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 03/17/2006] [Accepted: 04/10/2006] [Indexed: 10/24/2022] Open
Abstract
Intractable temporal lobe epilepsy presents an ideal target for gene therapy, but therapeutic success depends upon the ability to suppress limbic seizure activity. Adeno-associated virus vectors (AAV) were constructed in which the fibronectin secretory signal sequence (FIB) preceded the coding sequence for galanin (AAV-FIB-GAL) or green fluorescent protein (AAV-FIB-GFP), constructs that express and constitutively secrete the gene product. Bilateral AAV-FIB-GAL infusion into the rat piriform cortex (2 microl/side) significantly attenuated kainic acid-induced seizures (10 mg/kg, ip) such that 11/12 rats exhibited no limbic seizures, while the remaining rat exhibited only a brief, single class III seizure. This AAV-FIB-GAL infusion also prevented electrographic seizure activity. In contrast, bilateral AAV-FIB-GFP infusion did not alter either behavioral or electrographic seizure activity. Since prior seizure exposure could influence vector efficacy, another group of rats received daily electrical stimulation of the piriform cortex until three consecutive class V seizures were elicited. Subsequently, AAV-FIB-GAL or AAV-FIB-GFP (3 microl/30 min) was infused into the area of the electrode. One week later the AAV-FIB-GAL rats exhibited a significant increase in the stimulation current necessary to evoke limbic seizure activity, while AAV-FIB-GFP did not alter the seizure threshold. Thus, AAV-mediated galanin expression and secretion significantly suppress limbic seizure activity in vivo.
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Affiliation(s)
- Thomas J McCown
- Gene Therapy Center and Department of Psychiatry, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
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Echevarria DJ, Hernandez A, Diogenes A, Morilak DA. Administration of the galanin antagonist M40 into lateral septum attenuates shock probe defensive burying behavior in rats. Neuropeptides 2005; 39:445-51. [PMID: 16084587 DOI: 10.1016/j.npep.2005.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Accepted: 06/06/2005] [Indexed: 11/21/2022]
Abstract
Galanin (GAL) has been implicated in modulating anxiety, although a precise role remains unclear. Previous studies revealed anxiolytic effects, anxiogenic effects, or no effect, depending on the test, brain region, route of drug administration and context. We have shown previously that microinjection of the GAL antagonist M40 into central amygdala blocked an anxiolytic response to acute stress on the elevated plus maze when rats were pretreated with yohimbine, suggesting an anxiolytic effect of GAL. By contrast, we also showed that microinjection of M40 into the lateral bed nucleus of the stria terminalis attenuated anxiety-like behavioral responses to stress on the plus maze and social interaction tests, implying an anxiogenic effect for GAL. The behavioral response to stress on both these tests is a reduction of an ongoing behavior (open-arm exploration or social interaction, respectively). To better understand the anxiety-modulating role of GAL, it is also important to ascertain its effect on a response that represents an activation rather than suppression of behavior. Thus, in this study, we investigated an active behavioral response to acute stress in rats, the shock-probe defensive burying response. Bilateral microinjections of M40 into lateral septum (LS), a region important to this response and innervated by GAL, dose-dependently decreased burying without affecting immobility. No change was seen in hindpaw withdrawal latency on a thermosensitivity assay, suggesting that the reduction in burying behavior was not attributable to changes in cutaneous pain sensitivity. These results indicate that in LS, GAL facilitates the active anxiety-like behavioral response on the defensive burying test, similar to its facilitatory effect on anxiety-like stress-induced suppression of behavior in the lateral bed nucleus. These results highlight the fact that, rather than a unified system-like role in modulating anxiety, the effects of GAL can be either facilitating or attenuating, and are region-specific, context-specific and response-specific.
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Affiliation(s)
- David J Echevarria
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, United States
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Pirondi S, Kuteeva E, Giardino L, Ferraro L, Antonelli T, Bartfai T, Ogren SO, Hökfelt T, Calzà L. Behavioral and neurochemical studies on brain aging in galanin overexpressing mice. Neuropeptides 2005; 39:305-12. [PMID: 15944027 DOI: 10.1016/j.npep.2005.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [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: 01/20/2023]
Abstract
To study possible involvement of galanin in brain aging quality, we have investigated behavioral, neurochemical and morphological parameters in aged mice overexpressing galanin under the platelet-derived growth factor B promoter (GalOE mice) compared to wild-type littermates (WT mice). The behavioral analysis in the forced swim test showed that old GalOE animals spent more time in immobility compared to WT. In the activity cage test, galanin overexpression counteracted the age-induced decrease in exploratory behavior. The neurochemical analysis showed a 30% decrease in noradrenaline overflow in the cerebral cortex of WT old mice that was not present in age-matched GalOE mice. Our results indicate that overexpression of galanin can influence several behavioral and neurochemical parameters in old mice.
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Affiliation(s)
- S Pirondi
- Department of Veterinary Morphophysiology and Animal Production, University of Bologna, Bologna 40064, Italy
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Xu ZQD, Zheng K, Hökfelt T. Electrophysiological studies on galanin effects in brain--progress during the last six years. Neuropeptides 2005; 39:269-75. [PMID: 15944021 DOI: 10.1016/j.npep.2005.02.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 02/03/2005] [Indexed: 11/27/2022]
Abstract
The effects of galanin and galanin fragments have been studied on neurons in various brain regions of rodents using electrophysiological techniques. Here, we mainly review reports published during the last six years, that is after the second galanin symposium in 1998. These papers deal with locus coeruleus (LC), the hippocampal formation (HF), hypothalamus, the nucleus of the diagonal band of Broca (DBB) and the dorsal vagal complex (DVC). In most cases galanin has an inhibitory effect by increasing a potassium conductance or reducing a calcium conductance. In LC, beside a direct inhibitory effect, galanin exerts an indirect effect enhancing the noradrenaline-induced hyperpolarization. In the HF, galanin (1-15), but not galanin (1-29), induces hyperpolarization in CA3 pyramidal neurons. Inhibitory effects of galanin on several forms of synaptic plasticity including long-term potentiation, frequency facilitation and paired-pulse facilitation have also been demonstrated in normal and transgenic animals. In the hypothalamic arcuate nucleus galanin has a presynaptic action inhibiting glutamate release, as well as a postsynaptic effect via the galanin R1 receptor. In the DVC, galanin inhibits dorsal vagal motor neurons projecting to the stomach by activation of a postsynaptic galanin receptor. However, excitatory effects of galanin have also been reported in several regions, such as the DBB nucleus, where galanin increases excitability by decreasing a K+ conductance. Taken together, electrophysiological studies have further supported the role of galanin as a neurotransmitter/neuromodulator in the brain.
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Affiliation(s)
- Zhi-Qing David Xu
- Department of Neuroscience, Karolinska Institutet, S-171 71, Stockholm, Sweden.
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Abstract
Galanin plays an important role in the regulation of food intake, energy balance, and body weight. Many galanin-positive fibers as well as galanin-positive neurons were seen in the dorsal vagal complex, suggesting that galanin produces its effects by actions involving vagal neurons. In the present experiment, we used tract-tracing and neurophysiological techniques to evaluate the origin of the galaninergic fibers and the effect of galanin on neurons in the dorsal vagal complex. Our results reveal that the nucleus of the solitary tract is the major source of the galanin terminals in the dorsal vagal complex. In vivo experiments demonstrated that galanin inhibited the majority of gut-related neurons in the dorsal motor nucleus of the vagus. In vitro experiments demonstrated that galanin inhibited the majority of stomach-projecting neurons in the dorsal motor nucleus of the vagus by suppressing spontaneous activity and/or producing a fully reversible dose-dependent membrane hyperpolarization and outward current. The galanin-induced hyperpolarization and outward current persisted after synaptic input was blocked, suggesting that galanin acts directly on receptors of neurons in the dorsal motor nucleus of the vagus. The reversal potential induced by galanin was close to the potassium ion potentials of the Nernst equation and was prevented by the potassium channel blocker tetraethylammonium, indicating that the inhibitory effect of galanin was mediated by a potassium channel. These results indicate that the dorsal motor nucleus of the vagus is inhibited by galanin derived predominantly from neurons in the nucleus of the solitary tract projecting to the dorsal motor nucleus of the vagus nerve. Galanin is one of the neurotransmitters involved in the vago-vagal reflex.
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Affiliation(s)
- Zhenjun Tan
- Laboratory of Neurogastroenterology Research, Henry Ford Health System, Detroit, Michigan 48202, USA
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Holmes A, Heilig M, Rupniak NMJ, Steckler T, Griebel G. Neuropeptide systems as novel therapeutic targets for depression and anxiety disorders. Trends Pharmacol Sci 2003; 24:580-8. [PMID: 14607081 DOI: 10.1016/j.tips.2003.09.011] [Citation(s) in RCA: 303] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The health burden of stress-related diseases, including depression and anxiety disorders, is rapidly increasing, whereas the range of available pharmacotherapies to treat these disorders is limited and suboptimal with regard to efficacy and tolerability. Recent findings support a major role for neuropeptides in mediating the response to stress and thereby identify neuropeptide systems as potential novel therapeutic targets for the treatment of depression and anxiety disorders. In preclinical models, pharmacological and/or genetic manipulation of substance P, corticotropin-releasing factor (CRF), vasopressin, neuropeptide Y and galanin function alters anxiety- and depression-related responses. Recently, specific and highly potent small-molecule neuropeptide receptor agonists and antagonists have been developed that can readily cross the blood-brain barrier. Clinical assessment of several compounds is currently underway, with antidepressant efficacy confirmed in double-blind, placebo-controlled trials of tachykinin NK(1) (substance P) receptor antagonists, and preliminary evidence of antidepressant activity in an open-label trial of a CRF(1) receptor antagonist.
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MESH Headings
- Animals
- Antidiuretic Hormone Receptor Antagonists
- Anxiety Disorders/drug therapy
- Anxiety Disorders/metabolism
- Clinical Trials as Topic
- Depressive Disorder/drug therapy
- Depressive Disorder/metabolism
- Humans
- Neurokinin-1 Receptor Antagonists
- Receptors, Corticotropin-Releasing Hormone/agonists
- Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors
- Receptors, Corticotropin-Releasing Hormone/metabolism
- Receptors, Galanin/agonists
- Receptors, Galanin/antagonists & inhibitors
- Receptors, Galanin/metabolism
- Receptors, Neurokinin-1/agonists
- Receptors, Neurokinin-1/metabolism
- Receptors, Neuropeptide/agonists
- Receptors, Neuropeptide/antagonists & inhibitors
- Receptors, Neuropeptide/metabolism
- Receptors, Neuropeptide Y/agonists
- Receptors, Neuropeptide Y/antagonists & inhibitors
- Receptors, Neuropeptide Y/metabolism
- Receptors, Vasopressin/agonists
- Receptors, Vasopressin/metabolism
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Affiliation(s)
- Andrew Holmes
- Section on Behavioral Science and Genetics, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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Rodríguez MA, Anadón R, Rodríguez-Moldes I. Development of galanin-like immunoreactivity in the brain of the brown trout (Salmo trutta fario), with some observations on sexual dimorphism. J Comp Neurol 2003; 465:263-85. [PMID: 12949786 DOI: 10.1002/cne.10832] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The development of galanin-like immunoreactive (GAL-ir) cells and fibers was investigated in the brain of brown trout embryos, alevins, juveniles, and adults (some spontaneously releasing their gametes). The earliest GAL-ir neurons appeared in the preoptic region and the primordial hypothalamic lobe of 12-mm embryos. After hatching, new GAL-ir neurons appeared in the lateral, anterior, and posterior tuberal nuclei, and in late alevins, GAL-ir neurons appeared in the area postrema. In juveniles, further GAL-ir populations appeared in the nucleus subglomerulosus and magnocellular preoptic nucleus. The GAL-ir neuronal groups present in juveniles were also observed in sexually mature adults, although the area postrema of males lacked immunoreactive neurons. Moreover, spawning males exhibited GAL-ir somata in the olfactory bulb and habenula, which were never observed in adult females or in developing stages. In adults, numerous GAL-ir fibers were observed in the ventral telencephalon, preoptic area, hypothalamus, neurohypophysis, mesencephalic tegmentum, ventral rhombencephalon, and area postrema. Moderate to low GAL-ir innervation was seen in the olfactory bulbs, dorsomedial telencephalon, epithalamus, medial thalamus, optic tectum, cerebellum, and rhombencephalic alar plate. There were large differences among regions in the GAL-ir innervation establishment time. In embryos, GAL-ir fibers appeared in the preoptic area and hypothalamus, indicating early expression of galanin in hypophysiotrophic centers. The presence of galanin immunoreactivity in the olfactory, reproductive, visual, and sensory-motor centers of the brain suggest that galanin is involved in many other brain functions. Furthermore, the distribution of GAL-ir elements observed throughout trout development indicates that galaninergic system maturation continues until sexual maturity.
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Affiliation(s)
- Miguel Angel Rodríguez
- Department of Cell Biology and Ecology, Faculty of Biology, University of Santiago de Compostela, 15706 Santiago de Compostela, Spain
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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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Phelan KD, Newton BW. Sex differences in the response of postnatal rat lumbar lamina X neurons to exogenously applied galanin recorded in vitro. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 122:157-63. [PMID: 10960684 DOI: 10.1016/s0165-3806(00)00068-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Intracellular recording techniques were used in a horizontal slice preparation of postnatal rat lumbar spinal cord to compare the responses of male and female lamina X neurons to exogenously applied galanin. Although there was no significant sex difference in the resting membrane potential or input resistance of neurons, superfusion of galanin 1-16 (1 microM) produced a membrane hyperpolarization that averaged -5.3 mV in males and only -2.0 mV in females. The galanin-induced membrane hyperpolarization of lamina X neurons was accompanied by an inconsistent and varied change in input resistance. No depolarizing effect of galanin was detected in either sex. Galanin did not significantly alter the spike shape, amplitude, after hyperpolarization or locally evoked synaptic responses. The more than 2.5 fold significant sex difference in response to galanin occurred at a developmental timepoint at which lamina X expressed a comparably higher amount of galanin-like immunoreactivity in males compared to females. These results provide the first indication of a sex difference in the response of lamina X neurons to any neuropeptide. Given the antinociceptive role of galanin in the spinal cord, these results raise the possibility for the presence of distinct physiological and anatomical substrates for sex-dependent differences in nociceptive processing in lamina X of the lumbosacral spinal cord.
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Affiliation(s)
- K D Phelan
- Department of Anatomy/Slot 510, University of Arkansas for Medical Sciences, 4301 West Markham St., Little Rock, AR 72205, USA.
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Heppelmann B, Just S, Pawlak M. Galanin influences the mechanosensitivity of sensory endings in the rat knee joint. Eur J Neurosci 2000; 12:1567-72. [PMID: 10792434 DOI: 10.1046/j.1460-9568.2000.00045.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of the present study was to examine the effect of galanin on group III and IV afferent nerve fibres (n = 53) innervating normal and acutely inflamed knee joints in rats. They responded to local mechanical stimulation, movements of the joint and i.a. injections of KCl close to the joint. Single i.a. bolus injections of galanin (0.1 mM, 0.2 mL) caused no direct responses of the units. In normal and acutely inflamed joints, about half of the units did not change the responses to knee joint rotation. A significant reduction of the responses to noxious movements was found in approximately 40% of the units reaching a mean value of 57% in normal joints and 70% in inflamed joints compared with control movements. In approximately 10% the responses increased to 143% in normal joints and 120% in inflamed joints. Injection of a galanin receptor antagonist (M35) doubled the responses to noxious movements in 36% of the units in normal joints and reduced it in 18% to 86% of the control movements, indicating a tonic release and influence on the mechanosensitivity of a proportion of primary afferents by galanin. In conclusion, these data further support the hypothesis that the mechanosensitivity of fine afferent nerve fibres is regulated by a mixture of different substances being released into the innervated tissue. Besides the action of several pro-inflammatory peptides there seems to exist a tonic inhibitory system.
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Affiliation(s)
- B Heppelmann
- Physiologisches Institut, Universität Würzburg, Röntgenring 9, D-97070 Würzburg, Germany.
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