1
|
Neuroanatomical characterization of the G protein-coupled receptor activity evoked by galanin-related ligands. J Chem Neuroanat 2023; 128:102226. [PMID: 36566994 DOI: 10.1016/j.jchemneu.2022.102226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Galanin neuropeptide is distributed throughout the mammalian nervous system modulating a plethora of diverse physiological functions, including nociception, cognition and neuroendocrine regulation. The regulation of the galaninergic system is an interesting approach for the treatment of different diseases associated to those systems. Nevertheless, the pharmacological selectivity and activities of some galanin receptor (GalR) ligands are still in discussion and seem to depend on the dose, the receptor subtype and the second messengers to which they are coupled at different brain areas. The activity of different GalR ligands on Gi/o proteins, was evaluated by the guanosine 5'-(γ-[35S]thio)triphosphate ([35S]GTPγS) autoradiography in vitro assay applied to rat brain tissue slices in the presence of galanin, M15, M35, M40, gal(2-11) or galnon. The enhancement of the [35S]GTPγS binding induced by the chimerical peptides M15, M35 and M40 was similar to that produced by Gal in those brain areas showing the highest stimulations, such as dorsal part of the olfactory nucleus and ventral subiculum. In contrast to these peptides, using gal(2-11) no effect was measured on Gi/o protein coupling in areas of the rat brain with high GalR1 density such as posterior hypothalamic nucleus and amygdala, indicating low selectivity for GalR1 receptors. The effects evoked by the non-peptide ligand, galnon, were different from those induced by galanin, behaving as agonist or antagonist depending on the brain area, but the stimulations were always blocked by M35. Thus, the activity of most used GalR ligands on Gi/o protein mediated signalling is complex and depends on the brain area. More selective and potent GalR ligands are necessary to develop new treatments aimed to modulate the galaninergic system.
Collapse
|
2
|
Dysfunctional Heteroreceptor Complexes as Novel Targets for the Treatment of Major Depressive and Anxiety Disorders. Cells 2022; 11:cells11111826. [PMID: 35681521 PMCID: PMC9180493 DOI: 10.3390/cells11111826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/10/2022] [Accepted: 05/20/2022] [Indexed: 02/01/2023] Open
Abstract
Among mental diseases, major depressive disorder (MDD) and anxiety deserve a special place due to their high prevalence and their negative impact both on society and patients suffering from these disorders. Consequently, the development of novel strategies designed to treat them quickly and efficiently, without or at least having limited side effects, is considered a highly important goal. Growing evidence indicates that emerging properties are developed on recognition, trafficking, and signaling of G-protein coupled receptors (GPCRs) upon their heteromerization with other types of GPCRs, receptor tyrosine kinases, and ionotropic receptors such as N-methyl-D-aspartate (NMDA) receptors. Therefore, to develop new treatments for MDD and anxiety, it will be important to identify the most vulnerable heteroreceptor complexes involved in MDD and anxiety. This review focuses on how GPCRs, especially serotonin, dopamine, galanin, and opioid heteroreceptor complexes, modulate synaptic and volume transmission in the limbic networks of the brain. We attempt to provide information showing how these emerging concepts can contribute to finding new ways to treat both MDD and anxiety disorders.
Collapse
|
3
|
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.
Collapse
|
4
|
Hökfelt T, Barde S, Xu ZQD, Kuteeva E, Rüegg J, Le Maitre E, Risling M, Kehr J, Ihnatko R, Theodorsson E, Palkovits M, Deakin W, Bagdy G, Juhasz G, Prud’homme HJ, Mechawar N, Diaz-Heijtz R, Ögren SO. Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness. Front Neural Circuits 2018; 12:106. [PMID: 30627087 PMCID: PMC6309708 DOI: 10.3389/fncir.2018.00106] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022] Open
Abstract
Neuropeptides are auxiliary messenger molecules that always co-exist in nerve cells with one or more small molecule (classic) neurotransmitters. Neuropeptides act both as transmitters and trophic factors, and play a role particularly when the nervous system is challenged, as by injury, pain or stress. Here neuropeptides and coexistence in mammals are reviewed, but with special focus on the 29/30 amino acid galanin and its three receptors GalR1, -R2 and -R3. In particular, galanin's role as a co-transmitter in both rodent and human noradrenergic locus coeruleus (LC) neurons is addressed. Extensive experimental animal data strongly suggest a role for the galanin system in depression-like behavior. The translational potential of these results was tested by studying the galanin system in postmortem human brains, first in normal brains, and then in a comparison of five regions of brains obtained from depressed people who committed suicide, and from matched controls. The distribution of galanin and the four galanin system transcripts in the normal human brain was determined, and selective and parallel changes in levels of transcripts and DNA methylation for galanin and its three receptors were assessed in depressed patients who committed suicide: upregulation of transcripts, e.g., for galanin and GalR3 in LC, paralleled by a decrease in DNA methylation, suggesting involvement of epigenetic mechanisms. It is hypothesized that, when exposed to severe stress, the noradrenergic LC neurons fire in bursts and release galanin from their soma/dendrites. Galanin then acts on somato-dendritic, inhibitory galanin autoreceptors, opening potassium channels and inhibiting firing. The purpose of these autoreceptors is to act as a 'brake' to prevent overexcitation, a brake that is also part of resilience to stress that protects against depression. Depression then arises when the inhibition is too strong and long lasting - a maladaption, allostatic load, leading to depletion of NA levels in the forebrain. It is suggested that disinhibition by a galanin antagonist may have antidepressant activity by restoring forebrain NA levels. A role of galanin in depression is also supported by a recent candidate gene study, showing that variants in genes for galanin and its three receptors confer increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events. In summary, galanin, a neuropeptide coexisting in LC neurons, may participate in the mechanism underlying resilience against a serious and common disorder, MDD. Existing and further results may lead to an increased understanding of how this illness develops, which in turn could provide a basis for its treatment.
Collapse
Affiliation(s)
- Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Zhi-Qing David Xu
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Eugenia Kuteeva
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Joelle Rüegg
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- The Center for Molecular Medicine, Stockholm, Sweden
- Swedish Toxicology Sciences Research Center, Swetox, Södertälje, Sweden
| | - Erwan Le Maitre
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jan Kehr
- Pronexus Analytical AB, Solna, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Robert Ihnatko
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Miklos Palkovits
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - William Deakin
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
- NAP 2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | - Gabriella Juhasz
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- SE-NAP2 Genetic Brain Imaging Migraine Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | | | - Naguib Mechawar
- Douglas Hospital Research Centre, Verdun, QC, Canada
- Department of Psychiatry, McGill University, Montreal, QC, Canada
| | | | - Sven Ove Ögren
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
5
|
Alterations in the neuropeptide galanin system in major depressive disorder involve levels of transcripts, methylation, and peptide. Proc Natl Acad Sci U S A 2016; 113:E8472-E8481. [PMID: 27940914 DOI: 10.1073/pnas.1617824113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Major depressive disorder (MDD) is a substantial burden to patients, families, and society, but many patients cannot be treated adequately. Rodent experiments suggest that the neuropeptide galanin (GAL) and its three G protein-coupled receptors, GAL1-3, are involved in mood regulation. To explore the translational potential of these results, we assessed the transcript levels (by quantitative PCR), DNA methylation status (by bisulfite pyrosequencing), and GAL peptide by RIA of the GAL system in postmortem brains from depressed persons who had committed suicide and controls. Transcripts for all four members were detected and showed marked regional variations, GAL and galanin receptor 1 (GALR1) being most abundant. Striking increases in GAL and GALR3 mRNA levels, especially in the noradrenergic locus coeruleus and the dorsal raphe nucleus, in parallel with decreased DNA methylation, were found in both male and female suicide subjects as compared with controls. In contrast, GAL and GALR3 transcript levels were decreased, GALR1 was increased, and DNA methylation was increased in the dorsolateral prefrontal cortex of male suicide subjects, however, there were no changes in the anterior cingulate cortex. Thus, GAL and its receptor GALR3 are differentially methylated and expressed in brains of MDD subjects in a region- and sex-specific manner. Such an epigenetic modification in GALR3, a hyperpolarizing receptor, might contribute to the dysregulation of noradrenergic and serotonergic neurons implicated in the pathogenesis of MDD. Thus, one may speculate that a GAL3 antagonist could have antidepressant properties by disinhibiting the firing of these neurons, resulting in increased release of noradrenaline and serotonin in forebrain areas involved in mood regulation.
Collapse
|
6
|
Wang P, Li H, Barde S, Zhang MD, Sun J, Wang T, Zhang P, Luo H, Wang Y, Yang Y, Wang C, Svenningsson P, Theodorsson E, Hökfelt TGM, Xu ZQD. Depression-like behavior in rat: Involvement of galanin receptor subtype 1 in the ventral periaqueductal gray. Proc Natl Acad Sci U S A 2016; 113:E4726-35. [PMID: 27457954 PMCID: PMC4987783 DOI: 10.1073/pnas.1609198113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The neuropeptide galanin coexists in rat brain with serotonin in the dorsal raphe nucleus and with noradrenaline in the locus coeruleus (LC), and it has been suggested to be involved in depression. We studied rats exposed to chronic mild stress (CMS), a rodent model of depression. As expected, these rats showed several endophenotypes relevant to depression-like behavior compared with controls. All these endophenotypes were normalized after administration of a selective serotonin reuptake inhibitor. The transcripts for galanin and two of its receptors, galanin receptor 1 (GALR1) and GALR2, were analyzed with quantitative real-time PCR using laser capture microdissection in the following brain regions: the hippocampal formation, LC, and ventral periaqueductal gray (vPAG). Only Galr1 mRNA levels were significantly increased, and only in the latter region. After knocking down Galr1 in the vPAG with an siRNA technique, all parameters of the depressive behavioral phenotype were similar to controls. Thus, the depression-like behavior in rats exposed to CMS is likely related to an elevated expression of Galr1 in the vPAG, suggesting that a GALR1 antagonist could have antidepressant effects.
Collapse
Affiliation(s)
- Peng Wang
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Hui Li
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Ming-Dong Zhang
- Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden; Division of Molecular Neurobiology, Department of Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Jing Sun
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Tong Wang
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Pan Zhang
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Hanjiang Luo
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Yongjun Wang
- Anding Hospital, Capital Medical University, Beijing 100088, China
| | - Yutao Yang
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Chuanyue Wang
- Anding Hospital, Capital Medical University, Beijing 100088, China
| | - Per Svenningsson
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linkoping University, SE-58183 Linkoping, Sweden
| | - Tomas G M Hökfelt
- Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden;
| | - Zhi-Qing David Xu
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China;
| |
Collapse
|
7
|
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).
Collapse
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.
| |
Collapse
|
8
|
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.
Collapse
|
9
|
Duan H, Zhang Y, Zhang XM, Xu HH, Shu J, Xu SL. Antinociceptive roles of galanin receptor 1 in nucleus accumbens of rats in a model of neuropathic pain. J Neurosci Res 2015; 93:1542-51. [DOI: 10.1002/jnr.23611] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 05/27/2015] [Accepted: 06/01/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Hao Duan
- Department of Physiology; School of Basic Medicine, Kunming Medical University; Chenggong Kunming Yunnan People's Republic of China
- Department of Orthopedics, Second Affiliated Hospital; Kunming Medical University; Xishan Kunming Yunnan People's Republic of China
| | - Ying Zhang
- Department of Pathophysiology; School of Basic Medicine, Kunming Medical University; Chenggong Kunming Yunnan People's Republic of China
| | - Xiao-Min Zhang
- Department of Physiology; School of Basic Medicine, Kunming Medical University; Chenggong Kunming Yunnan People's Republic of China
| | - Huan-Huan Xu
- Department of Pathophysiology; School of Basic Medicine, Kunming Medical University; Chenggong Kunming Yunnan People's Republic of China
| | - Jun Shu
- Department of Orthopedics, Second Affiliated Hospital; Kunming Medical University; Xishan Kunming Yunnan People's Republic of China
| | - Shi-Lian Xu
- Department of Physiology; School of Basic Medicine, Kunming Medical University; Chenggong Kunming Yunnan People's Republic of China
| |
Collapse
|
10
|
Lang R, Gundlach AL, Holmes FE, Hobson SA, Wynick D, Hökfelt T, Kofler B. Physiology, signaling, and pharmacology of galanin peptides and receptors: three decades of emerging diversity. Pharmacol Rev 2015; 67:118-75. [PMID: 25428932 DOI: 10.1124/pr.112.006536] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galanin was first identified 30 years ago as a "classic neuropeptide," with actions primarily as a modulator of neurotransmission in the brain and peripheral nervous system. Other structurally-related peptides-galanin-like peptide and alarin-with diverse biologic actions in brain and other tissues have since been identified, although, unlike galanin, their cognate receptors are currently unknown. Over the last two decades, in addition to many neuronal actions, a number of nonneuronal actions of galanin and other galanin family peptides have been described. These include actions associated with neural stem cells, nonneuronal cells in the brain such as glia, endocrine functions, effects on metabolism, energy homeostasis, and paracrine effects in bone. Substantial new data also indicate an emerging role for galanin in innate immunity, inflammation, and cancer. Galanin has been shown to regulate its numerous physiologic and pathophysiological processes through interactions with three G protein-coupled receptors, GAL1, GAL2, and GAL3, and signaling via multiple transduction pathways, including inhibition of cAMP/PKA (GAL1, GAL3) and stimulation of phospholipase C (GAL2). In this review, we emphasize the importance of novel galanin receptor-specific agonists and antagonists. Also, other approaches, including new transgenic mouse lines (such as a recently characterized GAL3 knockout mouse) represent, in combination with viral-based techniques, critical tools required to better evaluate galanin system physiology. These in turn will help identify potential targets of the galanin/galanin-receptor systems in a diverse range of human diseases, including pain, mood disorders, epilepsy, neurodegenerative conditions, diabetes, and cancer.
Collapse
Affiliation(s)
- Roland Lang
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Andrew L Gundlach
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Fiona E Holmes
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Sally A Hobson
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - David Wynick
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Tomas Hökfelt
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Barbara Kofler
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| |
Collapse
|
11
|
Liu S, Borgland S. Regulation of the mesolimbic dopamine circuit by feeding peptides. Neuroscience 2015; 289:19-42. [DOI: 10.1016/j.neuroscience.2014.12.046] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/27/2014] [Accepted: 12/31/2014] [Indexed: 12/30/2022]
|
12
|
Barreda-Gómez G, Giralt MT, Pazos A, Rodríguez-Puertas R. Galanin activated Gi/o-proteins in human and rat central nervous systems. Neuropeptides 2014; 48:295-304. [PMID: 25043784 DOI: 10.1016/j.npep.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 05/19/2014] [Accepted: 06/16/2014] [Indexed: 11/29/2022]
Abstract
The neuropeptide galanin (GAL) is involved in the control of hormone secretion, nociception, feeding behavior, attention, learning and memory. The anatomical localization of galanin receptors in the brain has been described using autoradiography and immunohistochemistry, but both techniques are limited by the availability of specific radioligands or antibodies. Functional autoradiography provides an alternative method by combining anatomical resolution and information of the activity mediated by G-protein coupled receptors. The present study analyzes the functional GAL receptors coupled to Gi/o-proteins in human and rat brain nuclei using [(35)S]GTPγS autoradiography. The results show the anatomical distribution of Gi/o-proteins activated by GAL receptors that trigger intracellular signaling mechanisms. The activity mediated by GAL receptors in human and rat brain showed a good correlation of the net stimulation in areas such as spinal cord, periaqueductal gray, putamen, CA3 layers of hippocampus, substantia nigra and diverse thalamic nuclei. The functional GAL receptors coupled to Gi/o-proteins showed a similar pattern for both species in most of the areas analyzed, but some discrete nuclei showed differences in the activity mediated by GAL, such as the ventroposteromedial thalamic nucleus, or areas that regulate learning and memory processes in the hippocampus. Taken into consideration the present results, the rat could be used as an experimental model for the study of the physiological role of GAL-mediated neurotransmission and the modulation of GAL receptors activity in the human CNS.
Collapse
Affiliation(s)
- G Barreda-Gómez
- Dept. Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, E-48940 Leioa, Vizcaya, Spain
| | - M T Giralt
- Dept. Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, E-48940 Leioa, Vizcaya, Spain
| | - A Pazos
- Dept. Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, 39011 Santander, Spain
| | - R Rodríguez-Puertas
- Dept. Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, E-48940 Leioa, Vizcaya, Spain.
| |
Collapse
|
13
|
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
| |
Collapse
|
14
|
Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
Collapse
Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| |
Collapse
|
15
|
Borbély E, Scheich B, Helyes Z. Neuropeptides in learning and memory. Neuropeptides 2013; 47:439-50. [PMID: 24210137 DOI: 10.1016/j.npep.2013.10.012] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/14/2013] [Accepted: 10/14/2013] [Indexed: 12/14/2022]
Abstract
Dementia conditions and memory deficits of different origins (vascular, metabolic and primary neurodegenerative such as Alzheimer's and Parkinson's diseases) are getting more common and greater clinical problems recently in the aging population. Since the presently available cognitive enhancers have very limited therapeutical applications, there is an emerging need to elucidate the complex pathophysiological mechanisms, identify key mediators and novel targets for future drug development. Neuropeptides are widely distributed in brain regions responsible for learning and memory processes with special emphasis on the hippocampus, amygdala and the basal forebrain. They form networks with each other, and also have complex interactions with the cholinergic, glutamatergic, dopaminergic and GABA-ergic pathways. This review summarizes the extensive experimental data in the well-established rat and mouse models, as well as the few clinical results regarding the expression and the roles of the tachykinin system, somatostatin and the closely related cortistatin, vasoactive intestinal polypeptide (VIP) and pituitary adenylate-cyclase activating polypeptide (PACAP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), opioid peptides and galanin. Furthermore, the main receptorial targets, mechanisms and interactions are described in order to highlight the possible therapeutical potentials. Agents not only symptomatically improving the functional impairments, but also inhibiting the progression of the neurodegenerative processes would be breakthroughs in this area. The most promising mechanisms determined at the level of exploratory investigations in animal models of cognitive disfunctions are somatostatin sst4, NPY Y2, PACAP-VIP VPAC1, tachykinin NK3 and galanin GALR2 receptor agonisms, as well as delta opioid receptor antagonism. Potent and selective non-peptide ligands with good CNS penetration are needed for further characterization of these molecular pathways to complete the preclinical studies and decide if any of the above described targets could be appropriate for clinical investigations.
Collapse
Affiliation(s)
- Eva Borbély
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Szigeti u. 12, H-7624 Pécs, Hungary; Molecular Pharmacology Research Group, János Szentágothai Research Center, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
| | | | | |
Collapse
|
16
|
Robinson J, Smith A, Sturchler E, Tabrizifard S, Kamenecka T, McDonald P. Development of a high-throughput screening-compatible cell-based functional assay to identify small molecule probes of the galanin 3 receptor (GalR3). Assay Drug Dev Technol 2013; 11:468-77. [PMID: 24116939 DOI: 10.1089/adt.2013.526] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The galanin 3 receptor (GalR3) belongs to the large G protein-coupled receptor (GPCR) family of proteins. GalR3 and two other closely related receptors, GalR1 and GalR2, together with their endogenous ligand galanin, are involved in a variety of physiological and pathophysiological processes. GalR3 in particular has been strongly implicated in addiction and mood-related disorders such as anxiety and depression. It has been the target of many drug discovery programs within the pharmaceutical industry, but despite the significant resources and effort devoted to discovery of galanin receptor subtype selective small molecule modulators, there have been very few reports for the discovery of such molecules. GalR3 has proven difficult to enable in cell-based functional assays due to its apparent poor cell surface expression in recombinant systems. Here, we describe the generation of a modified GalR3 that facilitates its cell surface expression while maintaining wild-type receptor pharmacology. The modified GalR3 has been used to develop a high-throughput screening-compatible, cell-based, cAMP biosensor assay to detect selective small molecule modulators of GalR3. The performance of the assay has been validated by challenging it against a test library of small molecules with known pharmacological activities (LOPAC; Sigma Aldrich). This approach will enable identification of GalR3 selective modulators (chemical probes) that will facilitate dissection of the biological role(s) that GalR3 plays in normal physiological processes as well as in disease states.
Collapse
Affiliation(s)
- James Robinson
- 1 Department of Molecular Therapeutics, The Scripps Research Institute , Jupiter, Florida
| | | | | | | | | | | |
Collapse
|
17
|
Beck B, Pourié G. Ghrelin, neuropeptide Y, and other feeding-regulatory peptides active in the hippocampus: role in learning and memory. Nutr Rev 2013; 71:541-61. [PMID: 23865799 DOI: 10.1111/nure.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The hippocampus is a brain region of primary importance for neurogenesis, which occurs during early developmental states as well as during adulthood. Increases in neuronal proliferation and in neuronal death with age have been associated with drastic changes in memory and learning. Numerous neurotransmitters are involved in these processes, and some neuropeptides that mediate neurogenesis also modulate feeding behavior. Concomitantly, feeding peptides, which act primarily in the hypothalamus, are also present in the hippocampus. This review aims to ascertain the role of several important feeding peptides in cognitive functions, either through their local synthesis in the hippocampus or through their actions via specific receptors in the hippocampus. A link between neurogenesis and the orexigenic or anorexigenic properties of feeding peptides is discussed.
Collapse
Affiliation(s)
- Bernard Beck
- INSERM U954, Nutrition, Génétique et Expositions aux Risques Environnementaux, Faculté de Médecine, Vandœuvre, France.
| | | |
Collapse
|
18
|
Strom JO, Nilsson T, Theodorsson E. Effects of 17β-estradiol on galanin(1-29)- and galanin(1-16)-like immunoreactivities. Peptides 2013; 43:1-7. [PMID: 23402789 DOI: 10.1016/j.peptides.2013.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 11/21/2022]
Abstract
There are reasons to believe that the galanin neuropeptide family could include more than the two hitherto known members (galanin(1-29) and galanin-like peptide), such as the existence of at least three galanin receptors and the fact that synthetic short-chain homologues have effects and binding sites that are distinct from those of galanin(1-29). The current study uses a radioimmunoassay based on a polyclonal rabbit antiserum raised against galanin(1-16) to study the concentrations of galanin(1-16) like immunoreactivity (LI) in the various parts of the brain and gut of ovariectomized female rats, and investigates the effects of different concentrations of estradiol on these concentrations in relation to galanin(1-29)-LI. Galanin(1-29) concentrations were increased by 17β-estradiol administration in almost all examined tissues whereas galanin(1-16)-LI was increased by 17β-estradiol treatment in most of the gut, but only in the pituitary of the brain. Furthermore, the relation between galanin(1-29)-LI and galanin(1-16)-LI varied substantially from tissue to tissue. The main hypothesis, that galanin(1-16)-LI would be affected by 17β-estradiol in brain and/or gut, was confirmed in addition to the secondary hypothesis, stating that the pattern of galanin(1-16)-LI changes would differ from that of galanin(1-29). The study indicates that galanin(1-16)-LI is estrogen-responsive but that its concentrations are regulated differently from that of galanin(1-29). This is strongly indicative of a biological relevance of this potentially new member of the galanin neuropeptide family.
Collapse
Affiliation(s)
- Jakob O Strom
- Clinical Chemistry, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
| | | | | |
Collapse
|
19
|
Distinct features of neurotransmitter systems in the human brain with focus on the galanin system in locus coeruleus and dorsal raphe. Proc Natl Acad Sci U S A 2013; 110:E536-45. [PMID: 23341594 DOI: 10.1073/pnas.1221378110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Using riboprobe in situ hybridization, we studied the localization of the transcripts for the neuropeptide galanin and its receptors (GalR1-R3), tryptophan hydroxylase 2, tyrosine hydroxylase, and nitric oxide synthase as well as the three vesicular glutamate transporters (VGLUT 1-3) in the locus coeruleus (LC) and the dorsal raphe nucleus (DRN) regions of postmortem human brains. Quantitative real-time PCR (qPCR) was used also. Galanin and GalR3 mRNA were found in many noradrenergic LC neurons, and GalR3 overlapped with serotonin neurons in the DRN. The qPCR analysis at the LC level ranked the transcripts in the following order in the LC: galanin >> GalR3 >> GalR1 > GalR2; in the DRN the ranking was galanin >> GalR3 >> GalR1 = GalR2. In forebrain regions the ranking was GalR1 > galanin > GalR2. VGLUT1 and -2 were strongly expressed in the pontine nuclei but could not be detected in LC or serotonin neurons. VGLUT2 transcripts were found in very small, nonpigmented cells in the LC and in the lateral and dorsal aspects of the periaqueductal central gray. Nitric oxide synthase was not detected in serotonin neurons. These findings show distinct differences between the human brain and rodents, especially rat, in the distribution of the galanin system and some other transmitter systems. For example, GalR3 seems to be the important galanin receptor in both the human LC and DRN versus GalR1 and -2 in the rodent brain. Such knowledge may be important when considering therapeutic principles and drug development.
Collapse
|
20
|
Anderson ME, Runesson J, Saar I, Langel U, Robinson JK. Galanin, through GalR1 but not GalR2 receptors, decreases motivation at times of high appetitive behavior. Behav Brain Res 2012; 239:90-3. [PMID: 23142608 DOI: 10.1016/j.bbr.2012.10.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 01/20/2023]
Abstract
Galanin is a 29/30-amino acid long neuropeptide that has been implicated in many physiological and behavioral functions. Previous research has shown that i.c.v. administration of galanin strongly stimulates food intake in sated rats when food is freely available, but fails to stimulate this consumption when an operant response requirement is present. Using fixed ratio (FR) schedules, we sought to further clarify galanin's role in motivated behavior by administering galanin i.c.v. to rats working on fixed ratio schedules requiring either a low work condition (FR1) or higher work conditions (FR>1) to obtain a 0.2% saccharin reward. Rats in the FR>1 group were assigned to either an FR3, FR5 or FR7 schedule of reinforcement. The rate of reinforcement decreased for only the FR>1 group as compared to saline controls. Furthermore, injections of GalR1 receptor agonist M617 led to a similar, marginally significant decrease in the number of reinforcers received in the FR>1 condition, but a decrease was not seen after injections of GalR2 receptor agonist M1153. Taken together, these results show that galanin may be playing a role in decreasing motivation at times of high appetitive behavior, and that this effect is likely mediated by the GalR1 receptor.
Collapse
Affiliation(s)
- Maria E Anderson
- Department of Psychology, Stony Brook University, Stony Brook, NY 11794, USA
| | | | | | | | | |
Collapse
|
21
|
Holmes FE, Armenaki A, Iismaa TP, Einstein EB, Shine J, Picciotto MR, Wynick D, Zachariou V. Galanin negatively modulates opiate withdrawal via galanin receptor 1. Psychopharmacology (Berl) 2012; 220:619-25. [PMID: 21969124 PMCID: PMC3324978 DOI: 10.1007/s00213-011-2515-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 09/15/2011] [Indexed: 12/15/2022]
Abstract
RATIONALE The neuropeptide galanin has been shown to modulate opiate dependence and withdrawal. These effects could be mediated via activation of one or more of the three distinct G protein-coupled receptors, namely galanin receptors 1 (GalR1), 2 (GalR2), and 3 (GalR3). OBJECTIVES In this study, we used several transgenic mouse lines to further define the mechanisms underlying the role played by galanin and its receptors in the modulation of morphine dependence. First, transgenic mice expressing β-galactosidase under the control of the galanin promoter were used to assess the regulation of galanin expression in response to chronic morphine administration and withdrawal. Next, the behavioral responses to chronic morphine administration and withdrawal were tested in mice that over-express galanin, lack the GalR1 gene, or lack the GalR2 gene. METHODS Transgenic and matched wild-type mice were given increasing doses of morphine followed by precipitation of withdrawal by naloxone and behavioral responses to withdrawal were assessed. RESULTS Both morphine administration and withdrawal increased galanin gene transcription in the locus coeruleus (LC). Increasing galanin levels in the brain reduced signs of opiate withdrawal. Mice lacking GalR1 undergo more severe opiate withdrawal, whereas mice lacking GalR2 show no significant difference in withdrawal signs, compare with matched wild-type controls. CONCLUSIONS Opiate administration and withdrawal increase galanin expression in the LC. Galanin opposes the actions of morphine which leads to opiate dependence and withdrawal, an effect that is mediated via GalR1.
Collapse
MESH Headings
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Brain/metabolism
- Galanin/metabolism
- Gene Expression Regulation
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Morphine/administration & dosage
- Morphine/adverse effects
- Naloxone/pharmacology
- Narcotic Antagonists/pharmacology
- Opioid-Related Disorders/physiopathology
- Receptor, Galanin, Type 1/genetics
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/genetics
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/genetics
- Receptor, Galanin, Type 3/metabolism
- Substance Withdrawal Syndrome/physiopathology
Collapse
Affiliation(s)
- Fiona E Holmes
- Schools of Physiology and Pharmacology and Clinical Sciences, University of Bristol, Bristol, UK
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Fuxe K, Borroto-Escuela DO, Romero-Fernandez W, Tarakanov AO, Calvo F, Garriga P, Tena M, Narvaez M, Millón C, Parrado C, Ciruela F, Agnati LF, Narvaez JA, Díaz-Cabiale Z. On the existence and function of galanin receptor heteromers in the central nervous system. Front Endocrinol (Lausanne) 2012; 3:127. [PMID: 23112793 PMCID: PMC3481144 DOI: 10.3389/fendo.2012.00127] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 10/05/2012] [Indexed: 12/04/2022] Open
Abstract
Galanin receptor (GalR) subtypes 1-3 linked to central galanin neurons may form heteromers with each other and other types of G protein-coupled receptors in the central nervous system (CNS). These heteromers may be one molecular mechanism for galanin peptides and their N-terminal fragments (gal 1-15) to modulate the function of different types of glia-neuronal networks in the CNS, especially the emotional and the cardiovascular networks. GalR-5-HT1A heteromers likely exist with antagonistic GalR-5-HT1A receptor-receptor interactions in the ascending midbrain raphe 5-HT neuron systems and their target regions. They represent a novel target for antidepressant drugs. Evidence is given for the existence of GalR1-5-HT1A heteromers in cellular models with trans-inhibition of the protomer signaling. A GalR1-GalR2 heteromer is proposed to be a galanin N-terminal fragment preferring receptor (1-15) in the CNS. Furthermore, a GalR1-GalR2-5-HT1A heterotrimer is postulated to explain why only galanin (1-15) but not galanin (1-29) can antagonistically modulate the 5-HT1A receptors in the dorsal hippocampus rich in gal fragment binding sites. The results underline a putative role of different types of GalR-5-HT1A heteroreceptor complexes in depression. GalR antagonists may also have therapeutic actions in depression by blocking the antagonistic GalR-NPYY1 receptor interactions in putative GalR-NPYY1 receptor heteromers in the CNS resulting in increases in NPYY1 transmission and antidepressant effects. In contrast the galanin fragment receptor (a postulated GalR1-GalR2 heteromer) appears to be linked to the NPYY2 receptor enhancing the affinity of the NPYY2 binding sites in a putative GalR1-GalR2-NPYY2 heterotrimer. Finally, putative GalR-α2-adrenoreceptor heteromers with antagonistic receptor-receptor interactions may be a widespread mechanism in the CNS for integration of galanin and noradrenaline signals also of likely relevance for depression.
Collapse
Affiliation(s)
- Kjell Fuxe
- Department of Neuroscience, Karolinska InstitutetStockholm, Sweden
- *Correspondence: Kjell Fuxe, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden. e-mail:
| | | | | | - Alexander O. Tarakanov
- St. Petersburg Institute for Informatics and Automation, Russian Academy of SciencesSaint Petersburg, Russia
| | - Feliciano Calvo
- Department of Neuroscience, Karolinska InstitutetStockholm, Sweden
| | - Pere Garriga
- Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politécnica de CatalunyaBarcelona, Spain
| | - Mercé Tena
- Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politécnica de CatalunyaBarcelona, Spain
| | - Manuel Narvaez
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| | - Carmelo Millón
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| | - Concepción Parrado
- Department of Histology, School of Medicine, University of MálagaMálaga, Spain
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Universitat de BarcelonaBarcelona, Spain
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio EmiliaModena, Italy
- Istituto di Ricovero e Cura a Carattere ScientificoLido Venice, Italy
| | - José A. Narvaez
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| | - Zaida Díaz-Cabiale
- Department of Physiology, School of Medicine, University of MálagaMálaga, Spain
| |
Collapse
|
23
|
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]
|
24
|
Weinberg MS, McCown TJ. Current prospects and challenges for epilepsy gene therapy. Exp Neurol 2011; 244:27-35. [PMID: 22008258 DOI: 10.1016/j.expneurol.2011.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/16/2011] [Accepted: 10/03/2011] [Indexed: 12/25/2022]
Abstract
This review addresses the state of gene therapy research for the treatment of epilepsy. Preclinical studies have demonstrated the anti-seizure efficacy of viral vector-based gene transfer through the use of a variety of strategies - from modulating classic neurotransmitter systems to targeting or overexpressing of neuropeptide receptors in seizure-specific brain regions. While these studies provide substantive proof of principle for viral vector gene therapy, future studies must address the challenges of vector immunity, cellular specificity and effective global delivery. As these issues are resolved, viral vector gene therapy should significantly impact the treatment of intractable epilepsy.
Collapse
Affiliation(s)
- Marc S Weinberg
- University of North Carolina Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | | |
Collapse
|
25
|
Galanin receptor/Neuropeptide Y receptor interactions in the dorsal raphe nucleus of the rat. Neuropharmacology 2011; 61:80-6. [DOI: 10.1016/j.neuropharm.2011.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 02/28/2011] [Accepted: 03/01/2011] [Indexed: 12/22/2022]
|
26
|
Holm L, Theodorsson E, Hökfelt T, Theodorsson A. Effects of intracerebroventricular galanin or a galanin receptor 2/3 agonist on the lesion induced by transient occlusion of the middle cerebral artery in female rats. Neuropeptides 2011; 45:17-23. [PMID: 20974494 DOI: 10.1016/j.npep.2010.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 09/27/2010] [Accepted: 09/28/2010] [Indexed: 11/25/2022]
Abstract
Several studies have shown that injury to the central and peripheral nervous system can increase expression of galanin, a 29 amino acid neuropeptide. Moreover, there is evidence that galanin, especially through its galanin receptor 2 (GalR2) receptor, plays a neuroprotective role in different injury models. However, direct studies of a possible neuroprotective effect of galanin in experimental stroke models are lacking. Galanin, a GalR2/3 agonist or artificial CSF was continuously infused intracerebroventricularly (i.c.v.) in naïve female rats after a 60min transient and focal occlusion of the middle cerebral artery. The animals were sacrificed, and the ischemic lesion was visualized using 2,3,5-triphenyltetrazolium hydrochloride (TTC) staining. The lesion was 98% larger after i.c.v. administration of the GalR2/3 agonist (2.4nmol/day) seven days after occlusion compared to artificial CSF (p=0.023). No statistically significant differences were found after seven days in the groups treated with galanin in three different concentrations (0.24, 2.4 and 24nmol/day; p=0.939, 0.715 and 0.977, respectively). There was no difference in the size of the ischemic lesions measured after three days in the galanin-treated group (2.4nmol/d) compared to artificial CSF (p=0.925). The present results show, surprisingly, that a GalR2/3 agonist doubled the size of the ischemic lesion. Whether this effect primarily reflects the properties of the current model, species, gender and/or the mode of galanin administration, e.g. causing desensitization, or whether galanin indeed lacks neuroprotective effect of its own, remains to be corroborated.
Collapse
Affiliation(s)
- Lovisa Holm
- Department of Clinical and Experimental Medicine/Division of Clinical Chemistry, Linköping University, Linköping, Sweden
| | | | | | | |
Collapse
|
27
|
Pirondi S, Giuliani A, Del Vecchio G, Giardino L, Hökfelt T, Calzà L. The galanin receptor 2/3 agonist Gal2-11 protects the SN56 cells against beta-amyloid 25-35 toxicity. J Neurosci Res 2010; 88:1064-73. [PMID: 19885864 DOI: 10.1002/jnr.22278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The neuropeptide galanin is a modulator of cholinergic function and may play a role in A beta peptide-induced degeneration of cholinergic forebrain neurons. We have studied the effect of galanin and its galanin receptor subtype 2/3 agonist Gal2-11on toxicity induced by freshly-prepared beta-amyloid(25-35) in the cholinergic cell line SN56. Both nuclear fragmentation and caspase-3 expression were analysed. beta-amyloid(25-35)-exposure induced a significant increase in caspase-3 mRNA expression after 30, 60, 90 or 150 min of beta-amyloid(25-35) exposure. These effects were abolished in the presence of Gal2-11 (10 nM). Similarly, beta-amyloid(25-35)-induced nuclear fragmentation was prevented by the galanin agonist at all time points studied. These findings indicate that the galanin 2/3 agonist Gal2-11 protects SN56 cholinergic cells from beta-amyloid(25-35)-induced cell death and that this action is mediated by an early reduction of caspase-3 expression.
Collapse
Affiliation(s)
- S Pirondi
- DIMORFIPA, University of Bologna, Bologna, Italy
| | | | | | | | | | | |
Collapse
|
28
|
Galanin and consummatory behavior: special relationship with dietary fat, alcohol and circulating lipids. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:87-111. [PMID: 21299064 DOI: 10.1007/978-3-0346-0228-0_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Galanin (GAL) plays an integral role in consummatory behavior. In particular, hypothalamic GAL has a positive, reciprocal relationship with dietary fat and alcohol. In this relationship, GAL increases the consumption of fat or alcohol which, in turn, stimulates the expression of GAL, ultimately leading to overconsumption. Through actions in the amygdala, this relationship may become especially important in stress-induced food or drug intake. These effects of GAL in promoting overconsumption may involve various neurotransmitters, with GAL facilitating intake by stimulating norepinephrine and dopamine and reducing satiety by decreasing serotonin and acetylcholine. In addition, GAL in the hypothalamus stimulates the opioid, enkephalin, throughout the brain, which also promotes overconsumption. The relationship between GAL, fat, and alcohol may involve triglycerides, circulating lipids that are released by fat or alcohol and that correlate positively with hypothalamic GAL expression. In females, levels of endogenous GAL also fluctuate across the reproductive cycle, driven by a rise in the ovarian steroids, estrogen, and progesterone. They peak during the proestrous phase and also at puberty, simultaneous to a sharp increase in preference for fat to meet energy demands. Prenatal exposure to a high-fat diet also enhances hypothalamic expression of GAL into adulthood because of an increase in neurogenesis and proliferation of GAL-expressing neurons in this region. This organizational change may reflect the role of GAL in neuronal development, including neurite growth in adulthood, cell survival in aging, and cell stability in the disease state. By responding positively to fat and alcohol and guiding further neuronal development, GAL potentiates a long-term propensity to overconsume fat and alcohol.
Collapse
|
29
|
|
30
|
|
31
|
Dendritic synthesis and release of the neuropeptide galanin: Morphological evidence from studies on rat locus coeruleus neurons. J Comp Neurol 2009; 516:199-212. [DOI: 10.1002/cne.22105] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
32
|
Nagyéri G, Gálfi M, Radács M, Molnár AH, László F, Varga C, László FA. Effects of galanin-monoaminergic interactions on vasopressin secretion in rat neurohypophyseal cell cultures. ACTA ACUST UNITED AC 2009; 155:76-80. [PMID: 19289145 DOI: 10.1016/j.regpep.2009.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 03/04/2009] [Accepted: 03/07/2009] [Indexed: 11/28/2022]
Abstract
The effects of dopamine (DA), serotonin (5-HT), histamine (HA), adrenaline (ADR), noradrenaline (NADR) and K(+) administration on vasopressin (VP) secretion were studied in 13-14-day cultures of rat neurohypophyseal (NH) cells, and it was examined whether galanin (GAL) can modify the VP release enhancement induced by these monoaminergic compounds. An enzymatic dissociation technique was used to make the rat NH cell cultures. The VP contents of the supernatants of 14-day cultures were determined by radioimmunoassay. Following the administration of 10(-6) M GAL, the VP secretion into the supernatant media decreased. DA, 5-HT, ADR or NADR treatment increased the VP level substantially, while the enhancing effect of HA was more moderate. GAL administration before DA, ADR and NADR treatment prevented the VP concentration increase induced by DA, ADR or NADR. Preincubation with GAL reduced the 5-HT- or HA-induced VP level increases; the VP concentrations of the supernatant media remained above the control level. The GAL blocking effect was prevented by previous treatment with the GAL receptor antagonist galantid (M15). GAL had no effect on the VP level increase induced by K(+), which causes a non-specific hormone secretion. The results indicate that the changes in VP secretion induced by the monoaminergic system can be directly influenced by the GAL-ergic system. The interactions between the monoaminergic and GAL-ergic systems regarding VP secretion occur at the level of the posterior pituitary.
Collapse
Affiliation(s)
- Gy Nagyéri
- Department of Biology, Faculty of Juhász Gyula Teachers Training College, University of Szeged, Szeged, Hungary
| | | | | | | | | | | | | |
Collapse
|
33
|
Fuxe K, Marcellino D, Rivera A, Diaz-Cabiale Z, Filip M, Gago B, Roberts D, Langel U, Genedani S, Ferraro L, de la Calle A, Narvaez J, Tanganelli S, Woods A, Agnati L. Receptor–receptor interactions within receptor mosaics. Impact on neuropsychopharmacology. ACTA ACUST UNITED AC 2008; 58:415-52. [DOI: 10.1016/j.brainresrev.2007.11.007] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/26/2007] [Accepted: 11/29/2007] [Indexed: 01/01/2023]
|
34
|
Sanford SD, Gatlin JC, Hkfelt T, Pfenninger KH. Growth cone responses to growth and chemotropic factors. Eur J Neurosci 2008; 28:268-78. [DOI: 10.1111/j.1460-9568.2008.06327.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
35
|
Galanin: a potential role in mesolimbic dopamine-mediated instrumental behavior. Neurosci Biobehav Rev 2008; 32:1485-93. [PMID: 18632153 DOI: 10.1016/j.neubiorev.2008.05.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 05/20/2008] [Accepted: 05/27/2008] [Indexed: 11/21/2022]
Abstract
The involvement of the neuropeptide galanin in the consumption of the primary "commodities" of food and water is well established. However, the present review describes anatomical and behavioral evidence that suggests that galanin may also modulate ascending mesolimbic dopamine function and thereby play an inhibitory role in the systems by which instrumental behavior is energized toward acquiring primary commodities. General anatomical frameworks for this interaction are presented and future studies that could evaluate it are discussed.
Collapse
|
36
|
Rajarao SJR, Platt B, Sukoff SJ, Lin Q, Bender CN, Nieuwenhuijsen BW, Ring RH, Schechter LE, Rosenzweig-Lipson S, Beyer CE. Anxiolytic-like activity of the non-selective galanin receptor agonist, galnon. Neuropeptides 2007; 41:307-20. [PMID: 17637475 DOI: 10.1016/j.npep.2007.05.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 05/09/2007] [Accepted: 05/10/2007] [Indexed: 01/22/2023]
Abstract
Galanin's influence on monoaminergic neurotransmission, together with its discrete CNS distribution in corticolimbic brain areas, points to a potential role for this neuropeptide in mediating anxiety- and depression-like responses. To evaluate this hypothesis, the non-selective galanin receptor agonist, galnon, was tested in multiple preclinical models of anxiolytic- and antidepressive-like activity. Acute administration of galnon (0.03-1mg/kg, i.p.) dose-dependently increased punished crossings in the four plate test, with magnitude similar to the effects of the endogenous ligand, galanin (0.1-1.0 microg, i.c.v.). Moreover, the effects of galnon and galanin were blocked by central administration of the non-selective galanin receptor antagonist, M35 (10 microg, i.c.v.). Interestingly, the benzodiazepine receptor antagonist, flumazenil (1mg/kg, i.p.), reversed galnon's effect in the four plate test, implicating GABAergic neurotransmission as a potential mechanism underlying this anxiolytic-like response. In the elevated zero maze, galnon (0.3-3.0mg/kg, i.p.) and galanin (0.03-0.3 microg, i.c.v.) increased the time spent in the open arms, while in the stress-induced hyperthermia model, galnon (0.3-30 mg/kg, i.p.) attenuated stress-induced changes in body temperature. Consistent with these anxiolytic-like effects, in vivo microdialysis showed that acute galnon (3mg/kg, i.p.) treatment preferentially elevated levels of GABA in the rat amygdala, a brain area linked to fear and anxiety behaviors. In contrast to the effects in anxiety models, neither galnon (1-5.6 mg/kg, i.p.) nor galanin (0.3-3.0 microg, i.c.v.) demonstrated antidepressant-like effects in the mouse tail suspension test. Galnon (1-10mg/kg, i.p.) also failed to reduce immobility time in the rat forced swim test. In vitro, galnon and galanin showed affinity for human galanin receptors expressed in Bowes melanoma cells (K(i)=5.5 microM and 0.2 nM, respectively). Galanin displayed high affinity and functional potency for membranes expressing rat GALR1 receptors (K(i)=0.85 nM; EC(50)=0.6 nM), while galnon (10 microM) failed to displace radiolabeled galanin or inhibit cAMP production in the same GALR1 cell line. Galnon (10 microM) showed affinity for NPY1, NK2, M5, and somatostatin receptors but no affinity for galanin receptors expressed in rat hippocampal membranes. Taken together, the present series of studies demonstrate novel effects of galnon in various preclinical models of anxiety and highlight the galaninergic system as a novel therapeutic target for the treatment of anxiety-related disorders. Moreover, these data indicate rodent GALR1 receptors do not mediate galnon's in vivo activity.
Collapse
Affiliation(s)
- S Johannes R Rajarao
- Depression and Anxiety Research, Discovery Neuroscience, Wyeth Research, CN8000, Princeton, NJ 08543, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Eisenstein SA, Holmes PV. Chronic and voluntary exercise enhances learning of conditioned place preference to morphine in rats. Pharmacol Biochem Behav 2007; 86:607-15. [PMID: 17368736 DOI: 10.1016/j.pbb.2007.02.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 01/19/2007] [Accepted: 02/01/2007] [Indexed: 01/09/2023]
Abstract
Previous research has shown that brief and intermittent activity wheel running attenuates conditioned place preference (CPP) to morphine in rats, which suggests that exercise may produce a cross-tolerance to opiates. On the other hand, a different exercise paradigm, chronic and voluntary wheel running, enhances learning in contextual conditioning tasks. The present experiments tested CPP to 2.5, 5, and 7.5 mg/kg morphine in sedentary rats and rats provided free access to running wheels for three weeks. Sucrose preference was also tested to determine exercise's influence on appetitive processes. Levels of mRNA encoding brain-derived neurotrophic factor and preprogalanin mRNA were quantified using in situ hybridization. In rats that exhibited CPP to morphine, exercising rats spent significantly more time per entry in the morphine-paired chamber during the CPP test. CPP to morphine was dose-dependent. The expression of hippocampal brain-derived neurotrophic factor (BDNF) was greater in exercising rats compared to the sedentary group. Preprogalanin (GAL) mRNA expression in the locus coeruleus (LC) was positively correlated with mean distance run. These results suggest that while chronic exercise may produce cross-tolerance to opioids, exercise-induced enhancement of associative learning caused by exercise may override this effect in the conditioned place preference procedure.
Collapse
Affiliation(s)
- Sarah A Eisenstein
- Neuroscience and Behavior Program, Psychology Department, The University of Georgia, Athens, GA 30602, USA
| | | |
Collapse
|
38
|
Díaz-Cabiale Z, Parrado C, Fuxe K, Agnati L, Narváez JA. Receptor–receptor interactions in central cardiovascular regulation. Focus on neuropeptide/α2-adrenoreceptor interactions in the nucleus tractus solitarius. J Neural Transm (Vienna) 2006; 114:115-25. [PMID: 16988794 DOI: 10.1007/s00702-006-0559-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 07/11/2006] [Indexed: 02/02/2023]
Abstract
The nucleus tractus solitarii (NTS) is a key nucleus in central cardiovascular control. In this mechanism it is well known the role of the alpha(2)-adrenoreceptors for the modulation of the autonomic pathways. Moreover a number of neuropeptides described in the NTS, including Neuropeptide Y (NPY), Galanin (GAL) and Angiotensin II (Ang II), have different roles in regulating the cardiovascular function within this nucleus. We show in this review several data which help to understand how these neuropeptides (NPY, GAL and Ang II) could modulate the cardiovascular responses mediated through alpha(2)-adrenoreceptors in the NTS. Also we show for the first time the interactions between neuropeptides in the brain, specifically the interactions between NPY, GAL, and Ang II, and its functional relevance for central cardiovascular regulation. These data strength the role of neuropeptides on central autonomic control and provide some evidences to understand the neurochemical mechanisms involved in the cardiovascular responses from the NTS.
Collapse
|
39
|
Ogren SO, Kuteeva E, Hökfelt T, Kehr J. Galanin receptor antagonists : a potential novel pharmacological treatment for mood disorders. CNS Drugs 2006; 20:633-54. [PMID: 16863269 DOI: 10.2165/00023210-200620080-00003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The pathophysiology of mood disorders involves several genetic and social predisposing factors, as well as a dysregulated response to chronic stress. Accumulated evidence during the last two decades has implicated disturbances in brain serotonin and/or noradrenaline (norepinephrine) neurotransmission in the aetiology of depression. In fact, current pharmacological treatment for mood disorders is based on the use of drugs that act mainly by enhancing brain serotonin and noradrenaline neurotransmission by blockade of the active reuptake mechanism for these neurotransmitters. However, current antidepressant drugs have a delayed onset of therapeutic action, and a substantial number of patients do not respond adequately to them. In addition, these drugs have a number of adverse effects that limit patient compliance. In view of this, there is an intense search to identify novel (receptor) targets for antidepressant therapy. Recent studies have indicated that several neuropeptides and their receptors are potential candidates for the development of novel antidepressant treatment. In this context, galanin is of particular interest, since it is co-localised with serotonin in the dorsal raphe nucleus and with noradrenaline in the locus coeruleus, nuclei known to play a major role in affective disorders and in the action of antidepressant drugs. The actions of galanin are mediated by three receptor subtypes (GAL1, GAL2 and GAL3), which are coupled to different intracellular effector systems. Studies in rats have shown that galanin administered intracerebroventricularly is a potent inhibitor of mesencephalic serotonergic neurotransmission, as indicated by a long-lasting reduction in the release of serotonin in the hippocampus. This inhibitory effect is related to activation of the galanin receptors located on the dorsal raphe neurons. Moreover, intracerebroventricular galanin alters the gene expression of serotonin 5-HT1A autoreceptors in the dorsal raphe and also changes their functional activity. In addition, galanin produces a functional blockade of postsynaptic 5-HT1A receptor-mediated responses. Both pharmacological and genetic studies suggest a role for galanin in depression-like behaviour in rodent models. Transgenic mice overexpressing galanin under the control of the platelet-derived growth factor-beta promoter display increased immobility in the forced swim test. Intracerebroventricular administration of galanin in the rat increases depression-like behaviour, and this is fully blocked by the nonselective peptide galanin receptor antagonist M35. Importantly, M35 alone administered intracerebroventricularly produces an antidepressant-like effect. Recently, newly developed receptor-specific nonpeptidergic galanin GAL3 receptor antagonists (SNAP-37889 and SNAP-398299), which cross the blood-brain barrier after systemic administration, have shown antidepressant-like activity in several animal models. On the other hand, stimulation of the GAL2 receptor at the raphe level by local application of the GAL2 receptor agonist galanin (2-11) has been shown to increase serotonin levels in the hippocampus and dorsal raphe. These results indicate an important (mainly inhibitory) role of galanin as a regulator of brain serotonin and 5-HT1A receptor-mediated transmission, which may be of potential importance for understanding mood disorders and for the development of antidepressant drugs. Taken together, the present evidence suggests that antidepressant efficacy may be associated with compounds acting as antagonists at the GAL3 and/or possibly GAL1 receptors, and/or agonists at the GAL2 receptor.
Collapse
Affiliation(s)
- Sven Ove Ogren
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | |
Collapse
|
40
|
Díaz-Cabiale Z, Parrado C, Rivera A, de la Calle A, Agnati L, Fuxe K, Narváez JA. Galanin-neuropeptide Y (NPY) interactions in central cardiovascular control: involvement of the NPY Y1receptor subtype. Eur J Neurosci 2006; 24:499-508. [PMID: 16903855 DOI: 10.1111/j.1460-9568.2006.04937.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The interactions between neuropeptide Y (NPY), specifically through NPY Y(1) and Y(2) receptor subtypes, and galanin [GAL(1-29)] have been analysed at the cardiovascular level. The cardiovascular effects of intracisternal coinjections of GAL(1-29) with NPY or NPY Y(1) or Y(2) agonists, as well as quantitative receptor autoradiography of the binding characteristics of NPY Y(1) and Y(2) receptor subtypes in the nucleus of the solitary tract (NTS), in the presence or absence of GAL(1-29), have been investigated. The effects of coinjections of GAL(1-29) and the NPY Y(1) agonist on the expression of c-FOS immunoreactivity in the NTS were also studied. The coinjection of NPY with GAL(1-29) induced a significant vasopressor and tachycardic action with a maximum 40% increase (P < 0.001). The coinjection of the NPY Y(1) agonist and GAL(1-29) induced a similar increase in mean arterial pressure and heart rate as did NPY plus GAL(1-29), actions that were not observed with the NPY Y(2) agonist plus GAL(1-29). GAL(1-29), 3 nm, significantly and substantially (by approximately 40%) decreased NPY Y(1) agonist binding in the NTS. This effect was significantly blocked (P < 0.01) in the presence of the specific galanin antagonist M35. The NPY Y(2) agonist binding was not modified in the presence of GAL(1-29). At the c-FOS level, the coinjection of NPY Y(1) and GAL(1-29) significantly reduced the c-FOS-immunoreactive response induced by either of the two peptides. The present findings suggest the existence of a modulatory antagonistic effect of GAL(1-29) mediated via galanin receptors on the NPY Y(1) receptor subtype and its signalling within the NTS.
Collapse
Affiliation(s)
- Zaida Díaz-Cabiale
- Departamento de Fisiología, Facultad de Medicina, Campus de Teatinos s/n. 29080 Málaga, Spain
| | | | | | | | | | | | | |
Collapse
|
41
|
Wu X, Yu LC. Alternation of galanin in nociceptive modulation in the central nervous system of rats during morphine tolerance: A behavioral and immunohistochemical study. Brain Res 2006; 1086:85-91. [PMID: 16626663 DOI: 10.1016/j.brainres.2005.12.132] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 12/24/2005] [Accepted: 12/27/2005] [Indexed: 11/22/2022]
Abstract
The present study was performed to investigate the alternation of galanin in nociceptive modulation and galanin-like immunoreactivity in the central nervous system of rats after morphine tolerance. The hindpaw withdrawal latencies to both thermal and mechanical stimulation increased significantly after intracerebroventricular injection of 3 nmol of galanin in opioid-naive rats. The antinociceptive effect induced by galanin was attenuated remarkably at the same dose in morphine-tolerant rats. Furthermore, an up-regulation of galanin-like immunoreactivity in the arcuate nucleus of hypothalamus of morphine-tolerant rat was observed by immunohistochemical methods, whereas no significant changes were detected in periaqueductal gray. The present study demonstrated that there are alternations in both galanin-induced antinociception and galanin-like immunoreactivity in the brain of rat after morphine tolerance. The results suggest an involvement of galanin in the central nervous system in morphine tolerance.
Collapse
Affiliation(s)
- Xia Wu
- Neurobiology Laboratory and National Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing, 100871, PR China
| | | |
Collapse
|
42
|
Hilke S, Hökfelt T, Theodorsson E. A Short Estrogen-responsive N-terminal Galanin Homologue Found in Rat Brain and Gut with Antiserum Raised Against Rat Galanin(1-16). Neurochem Res 2006; 31:177-88. [PMID: 16586031 DOI: 10.1007/s11064-005-9007-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2005] [Indexed: 11/25/2022]
Abstract
Galanin-like peptide (GALP) is currently the only known galanin(1-29) homologue. However, three different galanin receptors, of which GalR3 exhibits comparatively low affinity for galanin(1-29), and molecular heterogeneity of immunoreactive galanin are arguments for presence of other endogenous galanin homologues. Since antibodies recognize three-dimensional structures of 3-5 amino acids in a peptide, we raised antibodies in rabbits against galanin(1-16) conjugated to bovine serum albumin, looking for the presence of endogenous N-terminal galanin homologues in rat tissues. The antiserum selected had 7,830 times higher avidity for galanin(1-16) compared to galanin(1-29). A single immunoreactive component with a Stokes radius of about 8 amino acids was found. Immunohistochemistry strongly suggested that this immunoreactivity is localised in the same neurons as galanin(1-29). Furthermore, its concentration was increased in response to estrogen treatment in the same brain regions as galanin(1-29), although not as rapidly. The present results indicate the presence of a novel endogenous N-terminal galanin homologue.
Collapse
Affiliation(s)
- Susanne Hilke
- Department of Biomedicine and Surgery, Division of Clinical Chemistry, Faculty of Health Sciences, University Hospital, SE-581 82 Linköping, Sweden.
| | | | | |
Collapse
|
43
|
Alexander SPH, Mathie A, Peters JA. Galanin. Br J Pharmacol 2006. [DOI: 10.1038/sj.bjp.0706615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
44
|
Xia CY, Yuan CX, Yuan CG. Galanin inhibits the proliferation of glial olfactory ensheathing cells. Neuropeptides 2005; 39:453-9. [PMID: 16143396 DOI: 10.1016/j.npep.2005.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 07/14/2005] [Indexed: 11/22/2022]
Abstract
The effect of galanin (GAL) on neural proliferation was studied in this article using olfactory ensheathing cells (OECs). OECs were isolated from newborn rat olfactory bulb and cultured in vitro. RT-PCR was used to determine the expression of GAL and its receptors in these cells. MTT analysis and LDH assay were used to detect the effects of GAL and the agonist, antagonist of GAL receptors on the proliferation of OECs. Results show that OECs express mRNAs for GAL and GAL receptor2 (GalR2) but not for the two other GAL receptors, GalR1 and GalR3. In addition, GAL and two receptor agonists, GAL1-11 and GAL2-11, can inhibit the proliferation of OECs significantly, but cause no cytotoxicity in the OECs population. Moreover, the influence can be blocked by M35, a nonspecific antagonist of GAL receptors. It is suggested that GAL is an inhibitory factor in regulating OECs proliferation.
Collapse
Affiliation(s)
- Chen-Yi Xia
- Department of Biology, School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | | | | |
Collapse
|
45
|
Pirondi S, Fernandez M, Schmidt R, Hökfelt T, Giardino L, Calzà L. The galanin-R2 agonist AR-M1896 reduces glutamate toxicity in primary neural hippocampal cells. J Neurochem 2005; 95:821-33. [PMID: 16248891 DOI: 10.1111/j.1471-4159.2005.03437.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Galanin is a neuropeptide involved in a variety of biological functions, including having a strong anticonvulsant activity. To assess a possible role of galanin in modulation of glutamatergic synapses and excitotoxicity, we studied effects of a galanin receptor 2(3) agonist (AR-M1896) on several molecular events induced by glutamate administration in primary neural hippocampal cells. Exposure of cells, after 5 days in vitro, to glutamate 0.5 mM for 10 min caused morphological alterations, including disaggregation of beta-tubulin and MAP-2 cytoskeletal protein assembly, loss of neurites and cell shrinkage. When present in culture medium together with glutamate, 1 and 10 nM of AR-M1896 reduced these alterations. Moreover, AR-M1896 counteracted glutamate-induced c-fos mRNA and c-Fos protein up-regulation after 30-150 min, and 24 h, respectively. Massive nuclear alterations (Hoechst 33258 staining), observed 24 h after glutamate exposure, were also antagonized by AR-M1896 (0.1-100 nM) in a dose-dependent manner. These findings indicate that galanin, probably mainly through its type 2 receptor, interferes with events associated with glutamate toxicity.
Collapse
Affiliation(s)
- Stefania Pirondi
- Department of Veterinary Morphophysiology and Animal Production, University of Bologna, Bologna, Italy
| | | | | | | | | | | |
Collapse
|
46
|
Kuteeva E, Hökfelt T, Ogren SO. Behavioural characterisation of transgenic mice overexpressing galanin under the PDGF-B promoter. Neuropeptides 2005; 39:299-304. [PMID: 15944026 DOI: 10.1016/j.npep.2005.01.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 01/05/2005] [Indexed: 01/22/2023]
Abstract
The behavioural phenotype of transgenic mice (3-5-months old) overexpressing galanin (GalOE mice) under the platelet-derived growth factor B (PDGF-B) promoter was evaluated in a battery of tests, including locomotor cages, light-dark exploration test, elevated plus-maze and the Porsolt forced swim test. Learning and memory were assessed in the Morris water maze task. GalOE mice showed a slight increase in spontaneous locomotor activity assessed in the locomotor cages, but the amphetamine-induced increase in locomotor activity was somewhat lower in GalOE mice. Anxiety-like behaviour in light-dark exploration and elevated plus-maze tests did not differ between genotypes. In the Porsolt forced swim test, GalOE mice displayed an increased time of immobility, indicative of increased learned helplessness possibly reflecting increased stress-susceptibility and/or depression-like behaviour. GalOE mice showed normal learning and memory retention in the Morris water maze tasks. These data support the hypothesis that galanin may have a role in functions related to mood states, including affective disorders.
Collapse
Affiliation(s)
- Eugenia Kuteeva
- Department of Neuroscience, Karolinska Institutet, Division of Behavioral Neuroscience, Retzius väg 8, S-171 77 Stockholm, Sweden
| | | | | |
Collapse
|
47
|
Barreda-Gómez G, Giralt MT, Rodríguez-Puertas R. G protein-coupled galanin receptor distribution in the rat central nervous system. Neuropeptides 2005; 39:153-6. [PMID: 15944004 DOI: 10.1016/j.npep.2004.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Accepted: 12/02/2004] [Indexed: 11/15/2022]
Abstract
The action of galanin in the central nervous system is mediated by at least three galanin receptor subtypes (GalR1, GalR2 and GalR3) which belong to the family of G protein-coupled receptors. GalR1 and GalR2 are coupled to G(i/o) proteins, although the latter may also be coupled to G(q/11) proteins. The aim of the present study was to identify the anatomical distribution and quantify the density of GalRs coupled to G proteins. The galanin (10(-6) M) stimulated guanosine 5'-(gamma-[35S] thio)triphosphate binding assay was used in tissue sections from the rat brain. Maximal percentages of stimulation over basal levels were found in the anterior olfactory nucleus and in the lateral olfactory tract nucleus ( approximately 54%). High levels of stimulation were recorded in diverse hypothalamic nuclei (16-28%), in the amygdala (central amygdaloid nucleus, 40%), in the spinal trigeminal tract (23%) and in layers 1-2 of the spinal cord (26%). Moderate binding stimulation (5-13%) was observed in thalamus, substantia nigra pars compacta, parabrachial nucleus, locus coeruleus and dorsal raphe nucleus. The lowest stimulation induced by galanin was recorded in diverse areas of the cortex, striatum, hippocampus and substantia nigra pars reticulata. The results show an anatomical distribution similar to that described for GalR1. However, in diverse brain areas, in which a high density of these receptors has previously been reported, only a moderate coupling to G proteins was found. These findings would suggest that the efficacy of galanin to induce an effective coupling of its receptors to G proteins could be different depending on the brain area.
Collapse
MESH Headings
- Amygdala/metabolism
- Animals
- Central Nervous System/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology
- Hypothalamus/metabolism
- Male
- Olfactory Pathways/metabolism
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Galanin/metabolism
- Spinal Cord/metabolism
- Sulfur Radioisotopes
- Trigeminal Nucleus, Spinal/metabolism
Collapse
Affiliation(s)
- G Barreda-Gómez
- Department of Pharmacology, Faculty of Medicine and Odontology, University of Basque Country, E-48940-Leioa, Vizcaya, Spain
| | | | | |
Collapse
|
48
|
Díaz-Cabiale Z, Parrado C, Vela C, Razani H, Coveñas R, Fuxe K, Narváez JA. Role of galanin and galanin(1-15) on central cardiovascular control. Neuropeptides 2005; 39:185-90. [PMID: 15944010 DOI: 10.1016/j.npep.2004.12.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Accepted: 12/02/2004] [Indexed: 11/18/2022]
Abstract
Galanin and the N-terminal fragment Galanin(1-15) are involved in central cardiovascular regulation. The present paper reviews the recent cardiovascular results obtained by intracisternal injections of Galanin and Galanin(1-15) showing that: (A) the Galanin antagonist M40 blocks the central cardiovascular responses induced by Galanin(1-15) but not those elicited by Galanin; (B) both Galanin and Galanin(1-15) induce the expression of c-Fos in cardiovascular nuclei of the medulla oblongata with different temporal and spatial profiles; (C) the cardiovascular action of Galanin(1-15), but not Galanin, is mediated by peripheral beta-receptor stimulation; (D) and it is demonstrated an antagonistic Galanin/alpha2-adrenoceptors interaction as well as a differential modulation of central cardiovascular responses of Angiotensin II by Galanin or Galanin(1-15). All these data strengthen the involvement of both Galanin molecules as neuromodulators on central cardiovascular regulation.
Collapse
Affiliation(s)
- Z Díaz-Cabiale
- Department of Physiology, Faculty of Medicine, University of Málaga, Campus de Teatinos s/n. 29080, Malaga, Spain
| | | | | | | | | | | | | |
Collapse
|
49
|
Hökfelt T. Galanin and its receptors: introduction to the Third International Symposium, San Diego, California, USA, 21-22 October 2004. Neuropeptides 2005; 39:125-42. [PMID: 15908000 DOI: 10.1016/j.npep.2005.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Third Galanin Symposium presented many different and exciting results on galanin research reflecting a major progress since the previous symposium in 1998. A major impression was the many possible relationships of galaninergic mechanisms to important brain functions such as development, cognition and ageing as well as many aspects related to a wide spectrum of diseases, including Alzheimer's disease, anxiety/depression, addiction, obesity, pain and tumour growth. These studies were based on an extensive armament of methodologies including various strains of transgenic mice. Unfortunately, the pharmaceutical industry had only a minor participation. Nevertheless, exciting developments in the generation of agonists and antagonists are emerging, providing hope that we at the next symposium will be able to validitate many of the challenging hypotheses concerning galanin and disease with the help of pharmacological tools.
Collapse
Affiliation(s)
- Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, S-171 77 Stockholm, Sweden.
| |
Collapse
|
50
|
Elvander E, Ogren SO. Medial septal galanin and acetylcholine: influence on hippocampal acetylcholine and spatial learning. Neuropeptides 2005; 39:245-8. [PMID: 15944017 DOI: 10.1016/j.npep.2004.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 12/07/2004] [Indexed: 11/24/2022]
Abstract
Neurochemical and behavioral studies in the rat have provided evidence for the view that galanin impairs learning via an inhibitory modulation of cholinergic neurons in the septohippocampal projection, believed to be important for learning and memory. To test this hypothesis, galanin was microinjected via a unilateral chronic cannula located in MS/dBB of rats. Infusion of galanin in the MS/dBB, which contains a high number of 125I-galanin binding sites, did not impair spatial acquisition or memory. On the contrary, spatial acquisition tended to be facilitated by 1 and 3 nmoles of galanin, while the 0.3 nmol dose had no effect. Intraseptal injections of scopolamine (10 microg/rat), a non-specific muscarinic antagonist, also failed to alter learning performance. In contrast, co-injections of galanin (3 nmol) and scopolamine (10 microg) resulted in a marked impairment of spatial acquisition. The effect of intraseptal galanin on basal acetylcholine release in the ventral hippocampus was examined by in vivo microdialysis and high-performance liquid chromatography. Both galanin (3 nmol/rat) and scopolamine (10 microg/rat) infused into the MS/dBB increased basal acetylcholine release in the ventral hippocampus. The combined injections of galanin and scopolamine resulted in an excessive increase in acetylcholine release. These results indicate, that galanin activates septohippocampal cholinergic neurons, suggesting that septal galanin may have a facilitatory role in spatial learning. Moreover, the level of muscarinic activity within the septal area appears to be critical for the effects of galanin on cognitive functions, since the combination of galanin and scopolamine produced a marked impairment in spatial learning, despite a marked increase in hippocampal acetylcholine release. In summary, a limited range of cholinergic muscarinic transmission may contribute to optimal hippocampal function, a finding that has important implications for therapeutic approaches in the treatment of disorders of memory function.
Collapse
Affiliation(s)
- E Elvander
- Department of Neuroscience, Division of Behavioral Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | | |
Collapse
|