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Bale R, Doshi G. Deciphering the Role of siRNA in Anxiety and Depression. Eur J Pharmacol 2024:176868. [PMID: 39128805 DOI: 10.1016/j.ejphar.2024.176868] [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: 01/04/2024] [Revised: 07/02/2024] [Accepted: 08/05/2024] [Indexed: 08/13/2024]
Abstract
Anxiety and depression are central nervous system illnesses that are among the most prevalent medical concerns of the twenty-first century. Patients with this condition and their families bear psychological, financial, and societal hardship. There are currently restrictions when utilizing the conventional course of treatment. RNA interference is expected to become an essential approach in anxiety and depression due to its potent and targeted gene silencing. Silencing of genes by post-transcriptional modification is the mechanism of action of small interfering RNA (siRNA). The suppression of genes linked to disease is typically accomplished by siRNA molecules in an efficient and targeted manner. Unfavourable immune responses, off-target effects, naked siRNA instability, nuclease vulnerability, and the requirement to create an appropriate delivery method are some of the challenges facing the clinical application of siRNA. This review focuses on the use of siRNA in the treatment of anxiety and depression.
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Affiliation(s)
- Rajeshwari Bale
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, V L M Road, Vile Parle (w), Mumbai, 400056, India
| | - Gaurav Doshi
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, V L M Road, Vile Parle (w), Mumbai, 400056, India.
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2
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Kojima R, Paslawski W, Lyu G, Arenas E, Zhang X, Svenningsson P. Secretome Analyses Identify FKBP4 as a GBA1-Associated Protein in CSF and iPS Cells from Parkinson's Disease Patients with GBA1 Mutations. Int J Mol Sci 2024; 25:683. [PMID: 38203854 PMCID: PMC10779269 DOI: 10.3390/ijms25010683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/12/2024] Open
Abstract
Mutations in the GBA1 gene increase the risk of developing Parkinson's disease (PD). However, most carriers of GBA1 mutations do not develop PD throughout their lives. The mechanisms of how GBA1 mutations contribute to PD pathogenesis remain unclear. Cerebrospinal fluid (CSF) is used for detecting pathological conditions of diseases, providing insights into the molecular mechanisms underlying neurodegenerative disorders. In this study, we utilized the proximity extension assay to examine the levels of metabolism-linked protein in the CSF from 17 PD patients carrying GBA1 mutations (GBA1-PD) and 17 idiopathic PD (iPD). The analysis of CSF secretome in GBA1-PD identified 11 significantly altered proteins, namely FKBP4, THOP1, GLRX, TXNDC5, GAL, SEMA3F, CRKL, APLP1, LRP11, CD164, and NPTXR. To investigate GBA1-associated CSF changes attributed to specific neuronal subtypes responsible for PD, we analyzed the cell culture supernatant from GBA1-PD-induced pluripotent stem cell (iPSC)-derived midbrain dopaminergic (mDA) neurons. The secretome analysis of GBA1-PD iPSC-derived mDA neurons revealed that five differently regulated proteins overlapped with those identified in the CSF analysis: FKBP4, THOP1, GLRX, GAL, and CRKL. Reduced intracellular level of the top hit, FKPB4, was confirmed via Western Blot. In conclusion, our findings identify significantly altered CSF GBA1-PD-associated proteins with FKPB4 being firmly attributed to mDA neurons.
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Affiliation(s)
- Rika Kojima
- Department of Clinical Neuroscience, Karolinska Institutet, 171 76 Stockholm, Sweden; (R.K.)
| | - Wojciech Paslawski
- Department of Clinical Neuroscience, Karolinska Institutet, 171 76 Stockholm, Sweden; (R.K.)
| | - Guochang Lyu
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Ernest Arenas
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Xiaoqun Zhang
- Department of Clinical Neuroscience, Karolinska Institutet, 171 76 Stockholm, Sweden; (R.K.)
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska Institutet, 171 76 Stockholm, Sweden; (R.K.)
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Involvement of Scratch2 in GalR1-mediated depression-like behaviors in the rat ventral periaqueductal gray. Proc Natl Acad Sci U S A 2021; 118:1922586118. [PMID: 34108238 DOI: 10.1073/pnas.1922586118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Galanin receptor1 (GalR1) transcript levels are elevated in the rat ventral periaqueductal gray (vPAG) after chronic mild stress (CMS) and are related to depression-like behavior. To explore the mechanisms underlying the elevated GalR1 expression, we carried out molecular biological experiments in vitro and in animal behavioral experiments in vivo. It was found that a restricted upstream region of the GalR1 gene, from -250 to -220, harbors an E-box and plays a negative role in the GalR1 promoter activity. The transcription factor Scratch2 bound to the E-box to down-regulate GalR1 promoter activity and lower expression levels of the GalR1 gene. The expression of Scratch2 was significantly decreased in the vPAG of CMS rats. Importantly, local knockdown of Scratch2 in the vPAG caused elevated expression of GalR1 in the same region, as well as depression-like behaviors. RNAscope analysis revealed that GalR1 mRNA is expressed together with Scratch2 in both GABA and glutamate neurons. Taking these data together, our study further supports the involvement of GalR1 in mood control and suggests a role for Scratch2 as a regulator of depression-like behavior by repressing the GalR1 gene in the vPAG.
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Mills EG, Izzi-Engbeaya C, Abbara A, Comninos AN, Dhillo WS. Functions of galanin, spexin and kisspeptin in metabolism, mood and behaviour. Nat Rev Endocrinol 2021; 17:97-113. [PMID: 33273729 DOI: 10.1038/s41574-020-00438-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The bioactive peptides galanin, spexin and kisspeptin have a common ancestral origin and their pathophysiological roles are increasingly the subject of investigation. Evidence suggests that these bioactive peptides play a role in the regulation of metabolism, pancreatic β-cell function, energy homeostasis, mood and behaviour in several species, including zebrafish, rodents and humans. Galanin signalling suppresses insulin secretion in animal models (but not in humans), is potently obesogenic and plays putative roles governing certain evolutionary behaviours and mood modulation. Spexin decreases insulin secretion and has potent anorectic, analgesic, anxiolytic and antidepressive-like effects in animal models. Kisspeptin modulates glucose-stimulated insulin secretion, food intake and/or energy expenditure in animal models and humans. Furthermore, kisspeptin is implicated in the control of reproductive behaviour in animals, modulation of human sexual and emotional brain processing, and has antidepressive and fear-suppressing effects. In addition, galanin-like peptide is a further member of the galaninergic family that plays emerging key roles in metabolism and behaviour. Therapeutic interventions targeting galanin, spexin and/or kisspeptin signalling pathways could therefore contribute to the treatment of conditions ranging from obesity to mood disorders. However, many gaps and controversies exist, which must be addressed before the therapeutic potential of these bioactive peptides can be established.
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Affiliation(s)
- Edouard G Mills
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Chioma Izzi-Engbeaya
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
- Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Ali Abbara
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
- Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Alexander N Comninos
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
- Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Waljit S Dhillo
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK.
- Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK.
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Yu M, Fang P, Wang H, Shen G, Zhang Z, Tang Z. Beneficial effects of galanin system on diabetic peripheral neuropathic pain and its complications. Peptides 2020; 134:170404. [PMID: 32898581 DOI: 10.1016/j.peptides.2020.170404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 11/16/2022]
Abstract
Diabetic peripheral neuropathic pain (DPNP) is a distal spontaneous pain, caused by lesion of sensory neurons and accompanied by depression and anxiety frequently, which reduce life quality of patients and increase society expenditure. To date, antidepressants, serotonin-noradrenaline reuptake inhibitors and anticonvulsants are addressed as first-line therapy to DPNP, alone or jointly. It is urgently necessary to develop novel agents to treat DPNP and its complications. Evidences indicate that neuropeptide galanin can regulate multiple physiologic and pathophysiological processes. Pain, depression and anxiety may upregulate galanin expression. In return, galanin can modulate depression, anxiety, pain threshold and pain behaviors. This article provides a new insight into regulative effects of galanin and its subtype receptors on antidepressant, antianxiety and against DPNP. Through activating GALR1, galanin reinforces depression-like and anxiogenic-like behaviors, but exerts antinociceptive roles. While via activating GALR2, galanin is referred to as anti-depressive and anti-anxiotropic compounds, and at low and high concentration facilitates and inhibits nociceptor activity, respectively. The mechanism of the galanin roles is relative to increase in K+ currents and decrease in Ca2+ currents, as well as neurotrophic and neuroprotective roles. These data are helpful to develop novel drugs to treat DPNP and its complications.
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Affiliation(s)
- Mei Yu
- Department of Physiology, School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, China; Department of Pharmacy, Taizhou Hospital of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Taizhou, Jiangsu, 225300, China
| | - Penghua Fang
- Department of Physiology, School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, China
| | - Hua Wang
- Department of Pharmacy, Taizhou Hospital of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Taizhou, Jiangsu, 225300, China
| | - Guiqin Shen
- Department of Pharmacy, Taizhou Hospital of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Taizhou, Jiangsu, 225300, China
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, 225001, China.
| | - Zongxiang Tang
- Department of Physiology, School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, China.
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Diet, Stress and Mental Health. Nutrients 2020; 12:nu12082428. [PMID: 32823562 PMCID: PMC7468813 DOI: 10.3390/nu12082428] [Citation(s) in RCA: 133] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/25/2020] [Accepted: 08/04/2020] [Indexed: 12/14/2022] Open
Abstract
Introduction: There has long been an interest in the effects of diet on mental health, and the interaction of the two with stress; however, the nature of these relationships is not well understood. Although associations between diet, obesity and the related metabolic syndrome (MetS), stress, and mental disorders exist, causal pathways have not been established. Methods: We reviewed the literature on the relationship between diet, stress, obesity and psychiatric disorders related to stress. Results: Diet and obesity can affect mood through direct effects, or stress-related mental disorders could lead to changes in diet habits that affect weight. Alternatively, common factors such as stress or predisposition could lead to both obesity and stress-related mental disorders, such as depression and posttraumatic stress disorder (PTSD). Specific aspects of diet can lead to acute changes in mood as well as stimulate inflammation, which has led to efforts to assess polyunsaturated fats (PUFA) as a treatment for depression. Bidirectional relationships between these different factors are also likely. Finally, there has been increased attention recently on the relationship between the gut and the brain, with the realization that the gut microbiome has an influence on brain function and probably also mood and behavior, introducing another way diet can influence mental health and disorders. Brain areas and neurotransmitters and neuropeptides that are involved in both mood and appetite likely play a role in mediating this relationship. Conclusions: Understanding the relationship between diet, stress and mood and behavior could have important implications for the treatment of both stress-related mental disorders and obesity.
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Demsie DG, Altaye BM, Weldekidan E, Gebremedhin H, Alema NM, Tefera MM, Bantie AT. Galanin Receptors as Drug Target for Novel Antidepressants: Review. Biologics 2020; 14:37-45. [PMID: 32368008 PMCID: PMC7183331 DOI: 10.2147/btt.s240715] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 03/19/2020] [Indexed: 11/23/2022]
Abstract
Galanin (GAL) is a 29-amino-acid neuropeptide that serves multiple physiological functions throughout the central and peripheral nervous system. Its role involves in a range of physiological and pathological functions including control of food intake, neuro-protection, neuronal regeneration, energy expenditure, reproduction, water balance, mood, nociception and various neuroendocrine functions. The use of currently available antidepressant drugs raises concerns regarding efficacy and onset of action; therefore, the need for antidepressants with novel mechanisms is increasing. Presently, various studies revealed the link between GAL and depression. Attenuation of depressive symptoms is achieved through inhibition of GalR1 and GalR3 and activation of GalR2. However, lack of receptor selectivity of ligands has limited the complete elucidation of effects of different receptors in depression-like behavior. Studies have suggested that GAL enhances the action of selective serotonin reuptake inhibitors (SSRIs) and promotes availability of transcription proteins. This review addresses the role of GAL, GAL receptors (GALRs) ligands including selective peptides, and the mechanism of ligand receptor interaction in attenuating depressive symptoms.
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Affiliation(s)
- Desalegn Getnet Demsie
- College of Medicine and Health Sciences, Department of Pharmacy, Adigrat University, Adigrat, Ethiopia
| | | | - Etsay Weldekidan
- College of Medicine and Health Sciences, Department of Pharmacy, Adigrat University, Adigrat, Ethiopia
| | - Hagazi Gebremedhin
- College of Medicine and Health Sciences, Department of Pharmacy, Adigrat University, Adigrat, Ethiopia
| | | | | | - Abere Tilahun Bantie
- College of Medicine and Health Sciences, Department of Anesthesia, Adigrat University, Adigrat, Ethiopia
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Tillage RP, Sciolino NR, Plummer NW, Lustberg D, Liles LC, Hsiang M, Powell JM, Smith KG, Jensen P, Weinshenker D. Elimination of galanin synthesis in noradrenergic neurons reduces galanin in select brain areas and promotes active coping behaviors. Brain Struct Funct 2020; 225:785-803. [PMID: 32065256 DOI: 10.1007/s00429-020-02035-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 01/27/2020] [Indexed: 01/08/2023]
Abstract
Accumulating evidence indicates that disruption of galanin signaling is associated with neuropsychiatric disease, but the precise functions of this neuropeptide remain largely unresolved due to lack of tools for experimentally disrupting its transmission in a cell type-specific manner. To examine the function of galanin in the noradrenergic system, we generated and crossed two novel knock-in mouse lines to create animals lacking galanin specifically in noradrenergic neurons (GalcKO-Dbh). We observed reduced levels of galanin peptide in pons, hippocampus, and prefrontal cortex of GalcKO-Dbh mice, indicating that noradrenergic neurons are a significant source of galanin to those brain regions, while midbrain and hypothalamic galanin levels were comparable to littermate controls. In these same brain regions, we observed no change in levels of norepinephrine or its major metabolite at baseline or after an acute stressor, suggesting that loss of galanin does not affect noradrenergic synthesis or turnover. GalcKO-Dbh mice had normal performance in tests of depression, learning, and motor-related behavior, but had an altered response in some anxiety-related tasks. Specifically, GalcKO-Dbh mice showed increased marble and shock probe burying and had a reduced latency to eat in a novel environment, indicative of a more proactive coping strategy. Together, these findings indicate that noradrenergic neurons provide a significant source of galanin to discrete brain areas, and noradrenergic-specific galanin opposes adaptive coping responses.
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Affiliation(s)
- Rachel P Tillage
- Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St., Atlanta, GA, 30322, USA
| | - Natale R Sciolino
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Nicholas W Plummer
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Daniel Lustberg
- Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St., Atlanta, GA, 30322, USA
| | - L Cameron Liles
- Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St., Atlanta, GA, 30322, USA
| | - Madeline Hsiang
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Jeanne M Powell
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Kathleen G Smith
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Patricia Jensen
- Neurobiology Laboratory, Developmental Neurobiology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA.
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St., Atlanta, GA, 30322, USA.
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Li Y, Gao M, Zeng K, Xing JX, Xu FL, Xuan JF, Xia X, Liu YP, Yao J, Wang BJ. Association Between Polymorphisms in the 5' Region of the GALR1 Gene and Schizophrenia in the Northern Chinese Han Population: A Case-Control Study. Neuropsychiatr Dis Treat 2020; 16:1519-1532. [PMID: 32606704 PMCID: PMC7306470 DOI: 10.2147/ndt.s256644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/22/2020] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Epidemiological studies have shown that genetic factors are among the causes of schizophrenia. Galanin receptor 1 is an inhibitory receptor of galanin that is widely distributed in the central nervous system. This study mainly explored the relationship between polymorphisms of the 5' region of the GALR1 gene and schizophrenia in the northern Chinese Han population. METHODS A 1545 bp fragment of the 5' regulatory region of the GALR1 gene was amplified and sequenced in 289 schizophrenia patients and 347 healthy controls. RESULTS Among the haplotypes composed of the 16 detected SNPs, the haplotype H3 was identified as conferring a risk of schizophrenia (p=0.011, OR=1.430, 95% CI=1.084-1.886). In addition, the haplotypes H4 and H7 were both protective against schizophrenia (p=0.024, OR=0.526, 95% CI=0.298-0.927; p=0.037, OR=0.197, 95% CI=0.044-0.885, respectively). In the subgroup analysis by sex, it was found that seven SNP alleles (rs72978691, rs11662010, rs11151014, rs11151015, rs13306374, rs5373, rs13306375) conferred a risk of schizophrenia in females (p<0.05), while allele G of rs7242919 (p=0.007) was protective against schizophrenia in females. Moreover, the rs72978691 AA+AC genotype (p=0.006, OR=1.874, 95% CI=1.196-2.937, power=0.780), rs7242919 CC+CG genotype (p=0.002, OR=2.027, 95% CI=1.292-3.180, power=0.861), rs11151014 GG+GT genotype (p=0.008, OR=1.834, 95% CI=1.168-2.879, power=0.735), rs11151015 GG+AG genotype (p=0.002, OR=2.013, 95% CI =1.291-3.137, power=0.843), rs13306374 CC+AC genotype (p=0.006, OR=1.881, 95% CI=1.198-2.953, power=0.788), and rs13306375 GG+AG genotype (p=0.006, OR=1.868, 95% CI=1.194-2.921, power=0.770) increased the risk of schizophrenia in females. The haplotype FH2 consisting of rs72978691, rs11662010, rs7242919, rs11151014, rs11151015, rs13306374, rs5373, and rs13306375 may also be associated with the risk of schizophrenia in females (p=0.024). CONCLUSION This study identified an association between polymorphisms in the 5' region of the GALR1 gene and schizophrenia, especially in females.
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Affiliation(s)
- Ya Li
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Meng Gao
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Kuo Zeng
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Jia-Xin Xing
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Feng-Ling Xu
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Jin-Feng Xuan
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Xi Xia
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Yong-Ping Liu
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Jun Yao
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
| | - Bao-Jie Wang
- School of Forensic Medicine, China Medical University, Shenyang 110122, People's Republic of China
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Flores-Burgess A, Millón C, Gago B, García-Durán L, Cantero-García N, Coveñas R, Narváez JA, Fuxe K, Santín L, Díaz-Cabiale Z. Galanin (1–15)-fluoxetine interaction in the novel object recognition test. Involvement of 5-HT1A receptors in the prefrontal cortex of the rats. Neuropharmacology 2019; 155:104-112. [DOI: 10.1016/j.neuropharm.2019.05.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 04/07/2019] [Accepted: 05/18/2019] [Indexed: 10/26/2022]
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Gołyszny M, Obuchowicz E. Are neuropeptides relevant for the mechanism of action of SSRIs? Neuropeptides 2019; 75:1-17. [PMID: 30824124 DOI: 10.1016/j.npep.2019.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 01/08/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are drugs of first choice in the therapy of moderate to severe depression and anxiety disorders. Their primary mechanism of action is via influence of the serotonergic (5-HT) system, but a growing amount of data provides evidence for other non-monoaminergic players in SSRI effects. It is assumed that neuropeptides, which play a role as neuromodulators in the CNS, are involved in their mechanism of action. In this review we focus on six neuropeptides: corticotropin-releasing factor - CRF, galanin - GAL, oxytocin - OT, vasopressin - AVP, neuropeptide Y - NPY, and orexins - OXs. First, information about their roles in depression and anxiety disorders are presented. Then, findings describing their interactions with the 5-HT system are summarized. These data provide background for analysis of the results of published preclinical and clinical studies related to SSRI effects on the neuropeptide systems. We also report findings showing how modulation of neuropeptide transmission influences behavioral and neurochemical effects of SSRIs. Finally, future research necessary for enriching our knowledge of SSRI mechanisms of action is proposed. Recognition of new molecular targets for antidepressants will have a significant effect on the development of novel therapeutic strategies for mood-related disorders.
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Affiliation(s)
- Miłosz Gołyszny
- Department of Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Poniatowskiego 15, 40-055 Katowice, Poland
| | - Ewa Obuchowicz
- Department of Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Poniatowskiego 15, 40-055 Katowice, Poland.
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12
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Millón C, Flores-Burgess A, Gago B, Alén F, Orio L, García-Durán L, Narváez JA, Fuxe K, Santín L, Díaz-Cabiale Z. Role of the galanin N-terminal fragment (1-15) in anhedonia: Involvement of the dopaminergic mesolimbic system. J Psychopharmacol 2019; 33:737-747. [PMID: 31081442 DOI: 10.1177/0269881119844188] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Anhedonia is a core feature of depressive disorders. The galanin N-terminal fragment (1-15) plays a role in mood regulation since it induces depression and anxiogenic-like effects in rats. In this study, we analysed galanin N-terminal fragment (1-15) actions in anhedonic-like behaviours in rats using operant and non-operant tests and the areas involved with these effects. METHODS Galanin N-terminal fragment (1-15) effects were analysed in saccharin self-administration, sucrose preference, novelty-suppressed feeding and female urine sniffing tests. The areas involved in galanin N-terminal fragment (1-15)-mediated effects were studied with positron emission tomography for in vivo imaging, and we analysed the ventral tegmental area and nucleus accumbens. Galanin N-terminal fragment (1-15) had effects on the mRNA expression of the dopamine transporters Dat and Vmat2; the C-Fos gene; the dopamine receptors D1, D2, D3, D5; and the galanin receptors 1 and 2. RESULTS Galanin N-terminal fragment (1-15) at a concentration of 3 nmol induced a strong anhedonia-like phenotype in all tests. The involvement of galanin receptor 2 was demonstrated with the galanin receptor 2 antagonist M871 (3 nmol). The 18F-fluorodeoxyglucose positron emission tomography images indicated the action of galanin N-terminal fragment (1-15) over several nuclei of the limbic system. Galanin N-terminal fragment (1-15)-mediated effects also involved changes in the expression of Dat, Vmat2, D3 and galanin receptors in the ventral tegmental area as well as the expression of C-Fos, D1, D2 and D3 and TH immunoreactivity in the nucleus accumbens. CONCLUSIONS Our results indicated that galanin N-terminal fragment (1-15) exerts strong anhedonic-like effects and that this effect was accompanied by changes in the dopaminergic mesolimbic system. These results may provide a basis for the development of novel therapeutic strategies using galanin N-terminal fragment (1-15) analogues for the treatment of depression and reward-related diseases.
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Affiliation(s)
- Carmelo Millón
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain.,2 Departamento de Psicobiología y Metodología en Ciencias del Comportamiento, Facultad de Psicología, Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio Flores-Burgess
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Belén Gago
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Francisco Alén
- 2 Departamento de Psicobiología y Metodología en Ciencias del Comportamiento, Facultad de Psicología, Universidad Complutense de Madrid, Madrid, Spain
| | - Laura Orio
- 2 Departamento de Psicobiología y Metodología en Ciencias del Comportamiento, Facultad de Psicología, Universidad Complutense de Madrid, Madrid, Spain
| | - Laura García-Durán
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - José A Narváez
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Kjell Fuxe
- 3 Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Luis Santín
- 4 Universidad de Málaga, Facultad de Psicología, Instituto de Investigación Biomédica de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
| | - Zaida Díaz-Cabiale
- 1 Universidad de Málaga, Facultad de Medicina, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga, Campus de Teatinos s/n, 29071, Málaga, Spain
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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.
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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
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de Souza MM, Silote GP, Herbst LS, Funck VR, Joca SRL, Beijamini V. The antidepressant-like effect of galanin in the dorsal raphe nucleus of rats involves GAL 2 receptors. Neurosci Lett 2018; 681:26-30. [PMID: 29787787 DOI: 10.1016/j.neulet.2018.05.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/18/2018] [Indexed: 01/27/2023]
Abstract
Galanin is a neuropeptide distributed in human and rat brain regions that are involved with emotional regulation, such as the dorsal raphe nucleus (DRN). Galanin effects in the DRN are mediated by GAL1 and GAL2 receptors. Intracerebral infusion of a GAL2 (AR-M1896) or a GAL1 (M617) agonist induced either antidepressant or depressive-like effect, respectively, in rats exposed to the forced swimming test (FST). However, it is not clear if GAL1 and/or GAL2 receptors present in the DRN would be involved in such effects. Therefore, we investigated the effects induced by intra-DRN infusion of galanin (0.3 nmol), AR-M1896 (1 nmol, GAL2 agonist), or M617 (GAL1 agonist) in rats exposed to the FST. Galanin and AR-M1896 intra-DRN administration induced antidepressant-like effect in the FST. However, M617 did not induce any change in the FST. Neither M617 nor AR-M1896 changed the locomotor activity of rats in the open field test. Intra-DRN pre-treatment with M871 (1 nmol), a selective GAL2 antagonist, counteracted the antidepressant-like effect induced by galanin. These results suggest that galanin signaling through GAL2 receptors in the DRN produces triggers antidepressant-like effect.
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Affiliation(s)
- Mayara Machado de Souza
- Department of Pharmaceutical Sciences, Health Science Centre, Federal University of Espirito Santo, Vitoria, ES, 29043-900, Brazil
| | - Gabriela Pandini Silote
- Department of Physics and Chemistry, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, SP, Brazil; Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES, 29043-900, Brazil
| | - Leticia Santos Herbst
- Department of Pharmaceutical Sciences, Health Science Centre, Federal University of Espirito Santo, Vitoria, ES, 29043-900, Brazil
| | - Vinicius Rafael Funck
- Biochemistry and Pharmacology Postgraduate Program, Health Science Center, Federal University of Espirito Santo, Vitoria, ES, 29043-900, Brazil
| | - Samia Regiane Lourenço Joca
- Department of Physics and Chemistry, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, SP, Brazil; Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
| | - Vanessa Beijamini
- Department of Pharmaceutical Sciences, Health Science Centre, Federal University of Espirito Santo, Vitoria, ES, 29043-900, Brazil.
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Chalermpalanupap T, Weinshenker D, Rorabaugh JM. Down but Not Out: The Consequences of Pretangle Tau in the Locus Coeruleus. Neural Plast 2017; 2017:7829507. [PMID: 29038736 PMCID: PMC5605916 DOI: 10.1155/2017/7829507] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/20/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
Degeneration of locus coeruleus (LC) is an underappreciated hallmark of Alzheimer's disease (AD). The LC is the main source of norepinephrine (NE) in the forebrain, and its degeneration is highly correlated with cognitive impairment and amyloid-beta (Aβ) and tangle pathology. Hyperphosphorylated tau in the LC is among the first detectable AD-like neuropathology in the brain, and while the LC/NE system impacts multiple aspects of AD (e.g., cognition, neuropathology, and neuroinflammation), the functional consequences of hyperphosphorylated tau accrual on LC neurons are not known. Recent evidence suggests that LC neurons accumulate aberrant tau species for decades before frank LC cell body degeneration occurs in AD, suggesting that a therapeutic window exists. In this review, we combine the literature on how pathogenic tau affects forebrain neurons with the known properties and degeneration patterns of LC neurons to synthesize hypotheses on hyperphosphorylated tau-induced dysfunction of LC neurons and the prion-like spread of pretangle tau from the LC to the forebrain. We also propose novel experiments using both in vitro and in vivo models to address the many questions surrounding the impact of hyperphosphorylated tau on LC neurons in AD and its role in disease progression.
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Affiliation(s)
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jacki M. Rorabaugh
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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16
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Fang P, Yu M, Wan D, Zhang L, Han L, Shen Z, Shi M, Zhu Y, Zhang Z, Bo P. Regulatory effects of galanin system on development of several age-related chronic diseases. Exp Gerontol 2017; 95:88-97. [DOI: 10.1016/j.exger.2017.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/21/2017] [Accepted: 04/24/2017] [Indexed: 02/07/2023]
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Millón C, Flores-Burgess A, Narváez M, Borroto-Escuela DO, Gago B, Santín L, Castilla-Ortega E, Narváez JÁ, Fuxe K, Díaz-Cabiale Z. The neuropeptides Galanin and Galanin(1-15) in depression-like behaviours. Neuropeptides 2017; 64:39-45. [PMID: 28196617 DOI: 10.1016/j.npep.2017.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/11/2022]
Abstract
Galanin is a 29 amino acid neuropeptide widely distributed in neurons within the central nervous system. Galanin exerts its biological activities through three different G protein-receptors and participates in a number of functions, including mood regulation. Not only Galanin but also Galanin N-terminal fragments like Galanin(1-15) are active at the central level. In this work, we review the latest findings in studies on Galanin and Galanin(1-15) in depression-related behaviours. Our focus is on animal models for depression, and we pay some attention to research data obtained in human studies. Since Serotonin (5-HT), especially through 5-HT1A, and Galanin receptors interact at both pre-and postsynaptic level, the development of drugs targeting potential GAL1-GAL2-5-HT1A heteroreceptor complexes linked to the raphe-hippocampal 5-HT neurons may represent new treatment strategies in depression.
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Affiliation(s)
- Carmelo Millón
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain.
| | - Antonio Flores-Burgess
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Manuel Narváez
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | | | - Belén Gago
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Luis Santín
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Psicología, Departamento de Psicobiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Estela Castilla-Ortega
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Psicología, Departamento de Psicobiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - José Ángel Narváez
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Zaida Díaz-Cabiale
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Departamento de Fisiología, Campus de Teatinos s/n, 29071 Málaga, Spain
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18
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Flores-Burgess A, Millón C, Gago B, Narváez M, Borroto-Escuela DO, Mengod G, Narváez JA, Fuxe K, Santín L, Díaz-Cabiale Z. Galanin (1-15) enhancement of the behavioral effects of Fluoxetine in the forced swimming test gives a new therapeutic strategy against depression. Neuropharmacology 2017; 118:233-241. [PMID: 28288814 DOI: 10.1016/j.neuropharm.2017.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/17/2017] [Accepted: 03/07/2017] [Indexed: 11/16/2022]
Abstract
The pharmacological treatment of major depression is mainly based on drugs elevating serotonergic (5-HT) activity. Specifically, selective 5-HT reuptake inhibitors, including Fluoxetine (FLX), are the most commonly used for treatment of major depression. However, the understanding of the mechanism of action of FLX beyond its effect of elevating 5-HT is limited. The interaction between serotoninergic system and neuropeptides signaling could be a key aspect. We examined the ability of the neuropeptide Galanin(1-15) [GAL(1-15)] to modulate the behavioral effects of FLX in the forced swimming test (FST) and studied feasible molecular mechanisms. The data show that GAL(1-15) enhances the antidepressant-like effects induced by FLX in the FST, and we demonstrate the involvement of GALR1/GALR2 heteroreceptor complex in the GAL(1-15)-mediated effect using in vivo rat models for siRNA GALR1 or GALR2 knockdown. Importantly, 5-HT1A receptors (5HT1A-R) also participate in the GAL(1-15)/FLX interactions since the 5HT1AR antagonist WAY100635 blocked the behavioral effects in the FST induced by the coadministration of GAL(1-15) and FLX. The mechanism underlying GAL(1-15)/FLX interactions affected the binding characteristics as well as the mRNA levels of 5-HT1A-R specifically in the dorsal hippocampus while leaving unaffected mRNA levels and affinity and binding sites of this receptor in the dorsal raphe. The results open up the possibility to use GAL(1-15) as for a combination therapy with FLX as a novel strategy for treatment of depression.
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Affiliation(s)
- Antonio Flores-Burgess
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Carmelo Millón
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Belén Gago
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Manuel Narváez
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain
| | | | - Guadalupe Mengod
- Department of Neurochemistry and Neuropharmacology, IIBB-CSIC,IDIBAPS,CIBERNED, Barcelona 08036, Spain
| | - José Angel Narváez
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Luis Santín
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Psicología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Zaida Díaz-Cabiale
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, Spain.
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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.
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20
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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.
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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;
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21
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Petschner P, Juhasz G, Tamasi V, Adori C, Tothfalusi L, Hökfelt T, Bagdy G. Chronic venlafaxine treatment fails to alter the levels of galanin system transcripts in normal rats. Neuropeptides 2016; 57:65-70. [PMID: 26891823 DOI: 10.1016/j.npep.2016.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/22/2016] [Accepted: 01/31/2016] [Indexed: 11/16/2022]
Abstract
It is widely accepted that efficacy and speed of current antidepressants' therapeutic effect are far from optimal. Thus, there is a need for the development of antidepressants with new mechanisms of action. The neuropeptide galanin and its receptors (GalR1, GalR2 and GalR3) are among the promising targets. However, it is not clear whether or not the galanin system is involved in the antidepressant effect exerted by the currently much used inhibitors of the reuptake of serotonin and/or noradrenaline. To answer this question we administered the selective serotonin and noradrenaline reuptake inhibitor (SNRI) venlafaxine (40mg/kg/day via osmotic minipumps) to normal rats and examined the levels of the transcripts for galanin and GalR1-3 after a 3-week venlafaxine treatment in the dorsal raphe, hippocampus and frontal cortex. These areas are known to be involved in the effects of antidepressants and in depression itself. Venlafaxine failed to alter the expression of any of the galanin system genes in these areas. Our results show that one of the most efficient, currently used SNRIs does not alter transcript levels of galanin or its three receptors in normal rats. These findings suggest that the pro- and antidepressive-like effects of galanin reported in animal experiments may employ a novel mechanism(s).
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Affiliation(s)
- Peter Petschner
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Gabriella Juhasz
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE-NAP B Genetic Brain Imaging Migraine Research Group, Hungarian Academy of Sciences, Semmelweis University, Hungary
| | - Viola Tamasi
- Department of Genetics-, Cell and Immunobiology, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Csaba Adori
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Laszlo Tothfalusi
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary
| | - Tomas Hökfelt
- Retzius Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177, Stockholm, Sweden
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, H-1089, Nagyvarad ter 4., Budapest, Hungary; MTA-SE Neuropsychopharmacology & Neurochemistry Research Group, H-1089, Nagyvarad ter 4., Budapest, Hungary.
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22
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Kawa L, Barde S, Arborelius UP, Theodorsson E, Agoston D, Risling M, Hökfelt T. Expression of galanin and its receptors are perturbed in a rodent model of mild, blast-induced traumatic brain injury. Exp Neurol 2016; 279:159-167. [PMID: 26928087 DOI: 10.1016/j.expneurol.2016.02.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 02/22/2016] [Accepted: 02/24/2016] [Indexed: 01/05/2023]
Abstract
The symptomatology, mood and cognitive disturbances seen in post-traumatic stress disorder (PTSD) and mild blast-induced traumatic brain injury (mbTBI) overlap considerably. However the pathological mechanisms underlying the two conditions are currently unknown. The neuropeptide galanin has been suggested to play a role in the development of stress and mood disorders. Here we applied bio- and histochemical methods with the aim to elucidate the nature of any changes in the expression of galanin and its receptors in a rodent model of mbTBI. In situ hybridization and quantitative polymerase chain reaction studies revealed significant, injury-induced changes, in some cases lasting at least for one week, in the mRNA levels of galanin and/or its three receptors, galanin receptor 1-3 (GalR1-3). Such changes were seen in several forebrain regions, and the locus coeruleus. In the ventral periaqueductal gray GalR1 mRNA levels were increased, while GalR2 were decreased. Analysis of galanin peptide levels using radioimmunoassay demonstrated an increase in several brain regions including the locus coeruleus, dorsal hippocampal formation and amygdala. These findings suggest a role for the galanin system in the endogenous response to mbTBI, and that pharmacological studies of the effects of activation or inhibition of different galanin receptors in combination with functional assays of behavioral recovery may reveal promising targets for new therapeutic strategies in mbTBI.
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Affiliation(s)
- Lizan Kawa
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden.
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
| | - Ulf P Arborelius
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
| | - Denes Agoston
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden; Department of Anatomy, Physiology and Genetics, The Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, United States
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden.
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE 171 77 Stockholm, Sweden
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23
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West CHK, Boss-Williams KA, Ritchie JC, Weiss JM. Reprint of: Locus coeruleus neuronal activity determines proclivity to consume alcohol in a selectively-bred line of rats that readily consumes alcohol. Alcohol 2016; 50:91-105. [PMID: 26873226 DOI: 10.1016/j.alcohol.2016.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 07/21/2015] [Accepted: 08/18/2015] [Indexed: 11/18/2022]
Abstract
Sprague-Dawley rats selectively-bred for susceptibility to stress in our laboratory (Susceptible, or SUS rats) voluntarily consume large amounts of alcohol, and amounts that have, as shown here, pharmacological effects, which normal rats will not do. In this paper, we explore neural events in the brain that underlie this propensity to readily consume alcohol. Activity of locus coeruleus neurons (LC), the major noradrenergic cell body concentration in the brain, influences firing of ventral tegmentum dopaminergic cell bodies of the mesocorticolimbic system (VTA-DA neurons), which mediate rewarding aspects of alcohol. We tested the hypothesis that in SUS rats alcohol potently suppresses LC activity to markedly diminish LC-mediated inhibition of VTA-DA neurons, which permits alcohol to greatly increase VTA-DA activity and rewarding aspects of alcohol. Electrophysiological single-unit recording of LC and VTA-DA activity showed that in SUS rats alcohol decreased LC burst firing much more than in normal rats and as a result markedly increased VTA-DA activity in SUS rats while having no such effect in normal rats. Consistent with this, in a behavioral test for reward using conditioned place preference (CPP), SUS rats showed alcohol, given by intraperitoneal (i.p.) injection, to be rewarding. Next, manipulation of LC activity by microinfusion of drugs into the LC region of SUS rats showed that (a) decreasing LC activity increased alcohol intake and increasing LC activity decreased alcohol intake in accord with the formulation described above, and (b) increasing LC activity blocked both the rewarding effect of alcohol in the CPP test and the usual alcohol-induced increase in VTA-DA single-unit activity seen in SUS rats. An important ancillary finding in the CPP test was that an increase in LC activity was rewarding by itself, while a decrease in LC activity was aversive; consequently, effects of LC manipulations on alcohol-related reward in the CPP test were perhaps even larger than evident in the test. Finally, when increased LC activity was associated with (i.e., conditioned to) i.p. alcohol, subsequent alcohol consumption by SUS rats was markedly reduced, indicating that SUS rats consume large amounts of alcohol because of rewarding physiological consequences requiring increased VTA-DA activity. The findings reported here are consistent with the view that the influence of alcohol on LC activity leading to changes in VTA-DA activity strongly affects alcohol-mediated reward, and may well be the basis of the proclivity of SUS rats to avidly consume alcohol.
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Affiliation(s)
- Charles H K West
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Katherine A Boss-Williams
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - James C Ritchie
- Department of Pathology, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Jay M Weiss
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA.
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Galanin (1-15) enhances the antidepressant effects of the 5-HT1A receptor agonist 8-OH-DPAT: involvement of the raphe-hippocampal 5-HT neuron system. Brain Struct Funct 2016; 221:4491-4504. [PMID: 26792005 DOI: 10.1007/s00429-015-1180-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/23/2015] [Indexed: 10/22/2022]
Abstract
Galanin N-terminal fragment (1-15) [GAL(1-15)] is associated with depression-related and anxiogenic-like effects in rats. In this study, we analyzed the ability of GAL(1-15) to modulate 5-HT1A receptors (5-HT1AR), a key receptor in depression. GAL(1-15) enhanced the antidepressant effects induced by the 5-HT1AR agonist 8-OH-DPAT in the forced swimming test. These effects were stronger than the ones induced by Galanin (GAL). This action involved interactions at receptor level since GAL(1-15) affected the binding characteristics and the mRNA levels of 5-HT1AR in the dorsal hippocampus and dorsal raphe. The involvement of the GALR2 was demonstrated with the GALR2 antagonist M871. Proximity ligation assay experiments indicated that 5-HT1AR are in close proximity with GALR1 and GALR2 in both regions and in raphe RN33B cells. The current results indicate that GAL(1-15) enhances the antidepressant effects induced by 8-OH-DPAT acting on 5-HT1AR operating as postjunctional or as autoreceptors. These results may give the basis for the development of drugs targeting potential GALR1-GALR2-5-HT1AR heteroreceptor complexes linked to the raphe-hippocampal 5-HT neurons for the treatment of depression.
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25
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Weinshenker D, Holmes PV. Regulation of neurological and neuropsychiatric phenotypes by locus coeruleus-derived galanin. Brain Res 2015; 1641:320-37. [PMID: 26607256 DOI: 10.1016/j.brainres.2015.11.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/27/2015] [Accepted: 11/12/2015] [Indexed: 12/28/2022]
Abstract
Decades of research confirm that noradrenergic locus coeruleus (LC) neurons are essential for arousal, attention, motivation, and stress responses. While most studies on LC transmission focused unsurprisingly on norepinephrine (NE), adrenergic signaling cannot account for all the consequences of LC activation. Galanin coexists with NE in the vast majority of LC neurons, yet the precise function of this neuropeptide has proved to be surprisingly elusive given our solid understanding of the LC system. To elucidate the contribution of galanin to LC physiology, here we briefly summarize the nature of stimuli that drive LC activity from a neuroanatomical perspective. We go on to describe the LC pathways in which galanin most likely exerts its effects on behavior, with a focus on addiction, depression, epilepsy, stress, and Alzheimer׳s disease. We propose a model in which LC-derived galanin has two distinct functions: as a neuromodulator, primarily acting via the galanin 1 receptor (GAL1), and as a trophic factor, primarily acting via galanin receptor 2 (GAL2). Finally, we discuss how the recent advances in neuropeptide detection, optogenetics and chemical genetics, and galanin receptor pharmacology can be harnessed to identify the roles of LC-derived galanin definitively. This article is part of a Special Issue entitled SI: Noradrenergic System.
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Affiliation(s)
- David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, 615 Michael St., Whitehead 301, Atlanta, GA 30322, USA.
| | - Philip V Holmes
- Neuroscience Program, Biomedical and Health Sciences Institute and Psychology Department, University of Georgia, Athens, GA 30602, USA.
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26
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West CHK, Boss-Williams KA, Ritchie JC, Weiss JM. Locus coeruleus neuronal activity determines proclivity to consume alcohol in a selectively-bred line of rats that readily consumes alcohol. Alcohol 2015; 49:691-705. [PMID: 26496795 DOI: 10.1016/j.alcohol.2015.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 07/21/2015] [Accepted: 08/18/2015] [Indexed: 02/02/2023]
Abstract
Sprague-Dawley rats selectively-bred for susceptibility to stress in our laboratory (Susceptible, or SUS rats) voluntarily consume large amounts of alcohol, and amounts that have, as shown here, pharmacological effects, which normal rats will not do. In this paper, we explore neural events in the brain that underlie this propensity to readily consume alcohol. Activity of locus coeruleus neurons (LC), the major noradrenergic cell body concentration in the brain, influences firing of ventral tegmentum dopaminergic cell bodies of the mesocorticolimbic system (VTA-DA neurons), which mediate rewarding aspects of alcohol. We tested the hypothesis that in SUS rats alcohol potently suppresses LC activity to markedly diminish LC-mediated inhibition of VTA-DA neurons, which permits alcohol to greatly increase VTA-DA activity and rewarding aspects of alcohol. Electrophysiological single-unit recording of LC and VTA-DA activity showed that in SUS rats alcohol decreased LC burst firing much more than in normal rats and as a result markedly increased VTA-DA activity in SUS rats while having no such effect in normal rats. Consistent with this, in a behavioral test for reward using conditioned place preference (CPP), SUS rats showed alcohol, given by intraperitoneal (i.p.) injection, to be rewarding. Next, manipulation of LC activity by microinfusion of drugs into the LC region of SUS rats showed that (a) decreasing LC activity increased alcohol intake and increasing LC activity decreased alcohol intake in accord with the formulation described above, and (b) increasing LC activity blocked both the rewarding effect of alcohol in the CPP test and the usual alcohol-induced increase in VTA-DA single-unit activity seen in SUS rats. An important ancillary finding in the CPP test was that an increase in LC activity was rewarding by itself, while a decrease in LC activity was aversive; consequently, effects of LC manipulations on alcohol-related reward in the CPP test were perhaps even larger than evident in the test. Finally, when increased LC activity was associated with (i.e., conditioned to) i.p. alcohol, subsequent alcohol consumption by SUS rats was markedly reduced, indicating that SUS rats consume large amounts of alcohol because of rewarding physiological consequences requiring increased VTA-DA activity. The findings reported here are consistent with the view that the influence of alcohol on LC activity leading to changes in VTA-DA activity strongly affects alcohol-mediated reward, and may well be the basis of the proclivity of SUS rats to avidly consume alcohol.
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Affiliation(s)
- Charles H K West
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Katherine A Boss-Williams
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - James C Ritchie
- Department of Pathology, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Jay M Weiss
- Department of Psychiatry and Behavioral Sciences, Emory University, School of Medicine, Woodruff Memorial Research Building (WMB), 4th Floor, 101 Woodruff Circle, Atlanta, GA 30322, USA.
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27
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Freimann K, Kurrikoff K, Langel Ü. Galanin receptors as a potential target for neurological disease. Expert Opin Ther Targets 2015. [PMID: 26220265 DOI: 10.1517/14728222.2015.1072513] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Galanin is a 29/30 amino acid long neuropeptide that is widely expressed in the brains of many mammals. Galanin exerts its biological activities through three different G protein-coupled receptors, GalR1, GalR2 and GalR3. The widespread distribution of galanin and its receptors in the CNS and the various physiological and pharmacological effects of galanin make the galanin receptors attractive drug targets. AREAS COVERED This review provides an overview of the role of galanin and its receptors in the CNS, the involvement of the galaninergic system in various neurological diseases and the development of new galanin receptor-specific ligands. EXPERT OPINION Recent advances and novel approaches in migrating the directions of subtype-selective ligand development and chemical modifications of the peptide backbone highlight the importance of the galanin neurochemical system as a potential target for drug development.
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Affiliation(s)
- Krista Freimann
- a 1 University of Tartu, Institute of Technology , Tartu, Estonia +372 737 4871 ;
| | - Kaido Kurrikoff
- b 2 University of Tartu, Institute of Technology , Tartu, Estonia
| | - Ülo Langel
- c 3 University of Tartu, Institute of Technology , Tartu, Estonia.,d 4 Stockholm University, Arrhenius Laboratories for Natural Science, Department of Neurochemistry , Stockholm, Sweden
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28
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Millón C, Flores-Burgess A, Narváez M, Borroto-Escuela DO, Santín L, Parrado C, Narváez JA, Fuxe K, Díaz-Cabiale Z. A role for galanin N-terminal fragment (1-15) in anxiety- and depression-related behaviors in rats. Int J Neuropsychopharmacol 2015; 18:pyu064. [PMID: 25522404 PMCID: PMC4360234 DOI: 10.1093/ijnp/pyu064] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Galanin (GAL) plays a role in mood regulation. In this study we analyzed the action of the active N-terminal fragment [GAL(1-15)] in anxiety- and depression-related behavioral tests in rats. METHODS The effect of GAL(1-15) was analyzed in the forced swimming test, tail suspension test, open field test, and light/dark test. The proximity of GAL1 and GAL2 receptors was examined with the proximity ligation assay (PLA). We tested the GAL receptors involved in GAL(1-15) effects with the GAL2 receptor antagonist M871 and with an in vivo model of siRNA GAL2 receptor knockdown or siRNA GAL1 receptor knockdown rats. The effects of GAL(1-15) were also studied in the cell line RN33B. RESULTS GAL(1-15) induced strong depression-like and anxiogenic-like effects in all the tests. These effects were stronger than the ones induced by GAL. The involvement of the GAL2 receptor was demonstrated with M871 and with the siRNA GAL2 receptor knockdown rats. The PLA indicated the possible existence of GAL1 and GAL2 heteroreceptor complexes in the dorsal hippocampus and especially in the dorsal raphe nucleus. In the siRNA GAL1 receptor knockdown rats the behavioral actions of GAL(1-15) disappeared, and in the siRNA GAL2 receptor knockdown rats the reductions of the behavioral actions of GAL(1-15) was linked to a disappearance of PLA. In the cell line RN33B, GAL(1-15) decreased 5-HT immunoreactivity more strongly than GAL. CONCLUSIONS Our results indicate that GAL(1-15) exerts strong depression-related and anxiogenic-like effects and may give the basis for the development of drugs targeting GAL1 and GAL2 heteroreceptor complexes in the raphe-limbic system for the treatment of depression and anxiety.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Zaida Díaz-Cabiale
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Campus de Teatinos s/n, 29071 Málaga, España (PhD Millón, Flores-Burgess, M Narváez, Parrado, JA Narváez, and Díaz-Cabiale); Department of Neuroscience, Karolinska Institute, Stockholm, Sweden (PhD Borroto-Escuela and Fuxe); Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Facultad de Psicología, Campus de Teatinos s/n, 29071 Málaga, España (PhD Santín).
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29
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Sciolino NR, Smith JM, Stranahan AM, Freeman KG, Edwards GL, Weinshenker D, Holmes PV. Galanin mediates features of neural and behavioral stress resilience afforded by exercise. Neuropharmacology 2015; 89:255-64. [PMID: 25301278 PMCID: PMC4250306 DOI: 10.1016/j.neuropharm.2014.09.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/23/2014] [Accepted: 09/28/2014] [Indexed: 12/15/2022]
Abstract
Exercise promotes resilience to stress and increases galanin in the locus coeruleus (LC), but the question of whether changes in galanin signaling mediate the stress-buffering effects of exercise has never been addressed. To test the contributions of galanin to stress resilience, male Sprague Dawley rats received intracerebroventricular (ICV) cannulation for drug delivery and frontocortical cannulation for microdialysis, and were housed with or without a running wheel for 21d. Rats were acutely injected with vehicle or the galanin receptor antagonist M40 and exposed to a single session of either footshock or no stress. Other groups received galanin, the galanin receptor antagonist M40, or vehicle chronically for 21d prior to the stress session. Microdialysis sampling occurred during stress exposure and anxiety-related behavior was measured on the following day in the elevated plus maze. Dendritic spines were visualized by Golgi impregnation in medial prefrontal cortex (mPFC) pyramidal neurons and quantified. Exercise increased galanin levels in the LC. Under non-stressed conditions, anxiety-related behavior and dopamine levels were comparable between exercised and sedentary rats. In contrast, exposure to stress reduced open arm exploration in sedentary rats but not in exercise rats or those treated chronically with ICV galanin, indicating improved resilience. Both exercise and chronic, ICV galanin prevented the increased dopamine overflow and loss of dendritic spines observed after stress in sedentary rats. Chronic, but not acute M40 administration blocked the resilience-promoting effects of exercise. The results indicate that increased galanin levels promote features of resilience at both behavioral and neural levels.
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Affiliation(s)
- N R Sciolino
- Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, USA.
| | - J M Smith
- Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, USA.
| | - A M Stranahan
- Physiology Department, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA.
| | - K G Freeman
- Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA.
| | - G L Edwards
- Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, USA; Physiology and Pharmacology, University of Georgia, Athens, GA 30602, USA.
| | - D Weinshenker
- Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - P V Holmes
- Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, USA; Psychology Department, University of Georgia, Athens, GA 30602, USA.
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30
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Alteration of behavioral changes and hippocampus galanin expression in chronic unpredictable mild stress-induced depression rats and effect of electroacupuncture treatment. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:179796. [PMID: 25530777 PMCID: PMC4233667 DOI: 10.1155/2014/179796] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 11/26/2022]
Abstract
To explore new noninvasive treatment options for depression, this study investigated the effects of electric acupuncture (EA) for depression rat models. Depression in rats was induced by unpredictable chronic mild stress (UCMS) combined with isolation for 21 days. Eighteen male Sprague-Dawley rats were randomly assigned into three groups: control, model, and EA groups. Rats were treated by EA once daily for 21 days. The results showed that body weight and sucrose consumption were significantly increased in EA group than in the model group. The crossing numbers and rearing numbers in the open field test significantly decreased in the model group but not in the EA group. And EA treatments upregulated levels of hippocampus galanin (Gal) in UCMS rats back to relative normal levels. The present study suggested that EA had antidepressant effects on UCMS model rats. The potential antidepressant effect may be related to upregulating Gal expression in hippocampus.
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31
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Jakob S, Schraut KG, Schmitt AG, Scholz CJ, Ortega G, Steinbusch HW, Lesch KP, van den Hove DLA. Differential effects of prenatal stress in female 5-HTT-deficient mice: towards molecular mechanisms of resilience. Dev Neurosci 2014; 36:454-64. [PMID: 25195605 DOI: 10.1159/000363695] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 05/13/2014] [Indexed: 11/19/2022] Open
Abstract
Prenatal stress (PS) exposure is known to increase the risk of developing emotional disorders like major depression in later life. However, some individuals do not succumb to adversity following developmental stress exposure, a phenomenon referred to as resilience. To date, the molecular mechanisms explaining why some subjects are vulnerable and others more resilient to PS are far from understood. Recently, we have shown that the serotonin transporter (5-HTT) gene may play a modulating role in rendering individuals susceptible or resilient to PS. However, it is not clear which molecular players are mediating the interaction between PS and the 5-Htt genotype in the context of vulnerability and resilience to PS. For this purpose, we performed a microarray study with the help of Affymetrix GeneChip® Mouse Genome 430 2.0 Array, in which we separated wild-type and heterozygous 5-Htt-deficient (5-Htt+/-) PS offspring into susceptible and resilient offspring according to their performance in the forced swim test. Performance-oriented LIMMA analysis on the mRNA expression microarray data was followed by subsequent Spearman's correlation analysis linking the individual qRT-PCR mRNA expression data to various anxiety- and depression-related behavioral and neuroendocrine measures. Results indicate that, amongst others, Fos-induced growth factor (Figf), galanin receptor 3 (Galr3), growth hormone (Gh) and prolactin (Prl) were differentially expressed specifically in resilient offspring when compared to controls, and that the hippocampal expression of these genes showed several strong correlations with various measures of the hypothalamus-pituitary-adrenal axis (re)activity. In conclusion, there seems to be an intricate interplay between the expression of Figf, Galr3, Gh and Prl and neuroendocrine regulation, which may be critical in mediating resilience to PS exposure. More insight into the exact role of these molecular players may significantly enhance the development of new treatment strategies for stress-related emotional disorders.
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Affiliation(s)
- Sissi Jakob
- Department of Neuroscience, School for Mental Health and Neuroscience (MHENS), Maastricht University, Maastricht, The Netherlands
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32
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Wang M, Chen Q, Li M, Zhou W, Ma T, Wang Y, Gu S. Alarin-induced antidepressant-like effects and their relationship with hypothalamus-pituitary-adrenal axis activity and brain derived neurotrophic factor levels in mice. Peptides 2014; 56:163-72. [PMID: 24768903 DOI: 10.1016/j.peptides.2014.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/11/2014] [Accepted: 04/11/2014] [Indexed: 12/22/2022]
Abstract
Alarin is a newly identified member of the galanin family of peptides. Galanin has been shown to exert regulatory effects on depression. Similar to galanin in distribution, alarin is also expressed in the medial amygdala and hypothalamus, i.e., regions interrelated with depression. However, it remains a puzzle whether alarin is involved in depression. Accordingly, we established the depression-like mouse model using behavioral tests to ascertain the possible involvement of alarin, with fluoxetine as a positive control. With the positive antidepressant-like effects of alarin, we further examined its relationship to HPA axis activity and brain-derived neurotrophic factor (BDNF) levels in different brain areas in a chronic unpredictable mild stress (CUMS) paradigm. In the acute studies, alarin produced a dose-related reduction in the immobility duration in tail suspension test (TST) in mice. In the open-field test, intracerebroventricular (i.c.v.) injection of alarin (1.0 nmol) did not impair locomotion or motor coordination in the treated mice. In the CUMS paradigm, alarin administration (1.0 nmol, i.c.v.) significantly improved murine behaviors (FST and locomotor activity), which was associated with a decrease in corticotropin-releasing hormone (CRH) mRNA levels in the hypothalamus, as well as a decline in serum levels of CRH, adrenocorticotropic hormone (ACTH) and corticosterone (CORT), all of which are key hormones of the HPA axis. Furthermore, alarin upregulated BDNF mRNA levels in the prefrontal cortex and hippocampus. These findings suggest that alarin may potentiate the development of new antidepressants, which would be further secured with the identification of its receptor(s).
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Affiliation(s)
- Ming Wang
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Qian Chen
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Mei Li
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Wei Zhou
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Tengfei Ma
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Yun Wang
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China
| | - Shuling Gu
- Department of Pharmacology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China.
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The potential antidepressant and antidiabetic effects of galanin system. Pharmacol Biochem Behav 2014; 120:82-7. [DOI: 10.1016/j.pbb.2014.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/17/2014] [Accepted: 02/22/2014] [Indexed: 11/17/2022]
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Abstract
The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems. It is a modulator of various physiological and pathological processes, and it mediates its effects via three G protein-coupled receptors (GAL1-3 receptors). A role for GAL as a modulator of mood and anxiety was suggested, because GAL and its receptors are highly expressed in limbic brain structures of rodents. In recent years, numerous studies of animal models have suggested an involvement of GAL and GAL1 and GAL2 receptors in anxiety- and depression-related behavior. However, to date, there is sparse literature implicating GAL3 receptors in behavioral functions. Therefore, we studied the behavior of GAL3 receptor-deficient (GAL3-KO) mice to elucidate whether GAL3 receptors are involved in mediating behavior-associated actions of GAL. The GAL3-KO mouse line exhibited normal breeding and physical development. In addition to behavioral tests, phenotypic characterization included analysis of hematology, amino acid profiles, metabolism, and sudomotor function. In contrast to WT littermates, male GAL3-KO mice exhibited an anxiety-like phenotype in the elevated plus maze, open field, and light/dark box tests, and they were less socially affiliated than WT animals to a stranger mouse in a social interaction test. In conclusion, our data suggest involvement of GAL3 receptors in GAL-mediated effects on mood, anxiety, and behavior, making it a possible target for alternative treatment strategies for mood disorders.
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Brain galanin system genes interact with life stresses in depression-related phenotypes. Proc Natl Acad Sci U S A 2014; 111:E1666-73. [PMID: 24706871 DOI: 10.1073/pnas.1403649111] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Galanin is a stress-inducible neuropeptide and cotransmitter in serotonin and norepinephrine neurons with a possible role in stress-related disorders. Here we report that variants in genes for galanin (GAL) and its receptors (GALR1, GALR2, GALR3), despite their disparate genomic loci, conferred increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events in a European white population cohort totaling 2,361 from Manchester, United Kingdom and Budapest, Hungary. Bayesian multivariate analysis revealed a greater relevance of galanin system genes in highly stressed subjects compared with subjects with moderate or low life stress. Using the same method, the effect of the galanin system genes was stronger than the effect of the well-studied 5-HTTLPR polymorphism in the serotonin transporter gene (SLC6A4). Conventional multivariate analysis using general linear models demonstrated that interaction of galanin system genes with life stressors explained more variance (1.7%, P = 0.005) than the life stress-only model. This effect replicated in independent analysis of the Manchester and Budapest subpopulations, and in males and females. The results suggest that the galanin pathway plays an important role in the pathogenesis of depression in humans by increasing the vulnerability to early and recent psychosocial stress. Correcting abnormal galanin function in depression could prove to be a novel target for drug development. The findings further emphasize the importance of modeling environmental interaction in finding new genes for depression.
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Kormos V, Gaszner B. Role of neuropeptides in anxiety, stress, and depression: from animals to humans. Neuropeptides 2013; 47:401-19. [PMID: 24210138 DOI: 10.1016/j.npep.2013.10.014] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/07/2013] [Accepted: 10/09/2013] [Indexed: 12/11/2022]
Abstract
Major depression, with its strikingly high prevalence, is the most common cause of disability in communities of Western type, according to data of the World Health Organization. Stress-related mood disorders, besides their deleterious effects on the patient itself, also challenge the healthcare systems with their great social and economic impact. Our knowledge on the neurobiology of these conditions is less than sufficient as exemplified by the high proportion of patients who do not respond to currently available medications targeting monoaminergic systems. The search for new therapeutical strategies became therefore a "hot topic" in neuroscience, and there is a large body of evidence suggesting that brain neuropeptides not only participate is stress physiology, but they may also have clinical relevance. Based on data obtained in animal studies, neuropeptides and their receptors might be targeted by new candidate neuropharmacons with the hope that they will become important and effective tools in the management of stress related mood disorders. In this review, we attempt to summarize the latest evidence obtained using animal models for mood disorders, genetically modified rodent models for anxiety and depression, and we will pay some attention to previously published clinical data on corticotropin releasing factor, urocortin 1, urocortin 2, urocortin 3, arginine-vasopressin, neuropeptide Y, pituitary adenylate-cyclase activating polypeptide, neuropeptide S, oxytocin, substance P and galanin fields of stress research.
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Affiliation(s)
- Viktória Kormos
- 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; Department of Anatomy, Faculty of Medicine, University of Pécs, Szigeti u. 12, H-7624 Pécs, Hungary
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37
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The role of galanin system in modulating depression, anxiety, and addiction-like behaviors after chronic restraint stress. Neuroscience 2013; 246:82-93. [DOI: 10.1016/j.neuroscience.2013.04.046] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 11/21/2022]
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Ferrucci M, Giorgi FS, Bartalucci A, Busceti CL, Fornai F. The effects of locus coeruleus and norepinephrine in methamphetamine toxicity. Curr Neuropharmacol 2013; 11:80-94. [PMID: 23814540 PMCID: PMC3580794 DOI: 10.2174/157015913804999522] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/25/2012] [Accepted: 08/08/2012] [Indexed: 12/03/2022] Open
Abstract
The activity of locus coeruleus (LC) neurons has been extensively investigated in a variety of behavioural states. In fact this norepinephrine (NE)-containing nucleus modulates many physiological and pathological conditions including the sleep-waking cycle, movement disorders, mood alterations, convulsive seizures, and the effects of drugs such as psychostimulants and opioids. This review focuses on the modulation exerted by central NE pathways on the behavioural and neurotoxic effects produced by the psychostimulant methamphetamine, essentially the modulation of the activity of mesencephalic dopamine (DA) neurons. In fact, although NE in itself mediates some behavioural effects induced by methamphetamine, NE modulation of DA release is pivotal for methamphetamine-induced behavioural states and neurotoxicity. These interactions are discussed on the basis of the state of the art of the functional neuroanatomy of central NE- and DA systems. Emphasis is given to those brain sites possessing a remarkable overlapping of both neurotransmitters.
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Affiliation(s)
- Michela Ferrucci
- Department of Human Morphology and Applied Biology, University of Pisa, Pisa, Italy
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Saar I, Lahe J, Langel K, Runesson J, Webling K, Järv J, Rytkönen J, Närvänen A, Bartfai T, Kurrikoff K, Langel Ü. Novel systemically active galanin receptor 2 ligands in depression-like behavior. J Neurochem 2013; 127:114-23. [PMID: 23600864 DOI: 10.1111/jnc.12274] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/31/2013] [Accepted: 03/31/2013] [Indexed: 11/30/2022]
Abstract
Neuropeptide galanin and its three G-protein coupled receptors, galanin receptor type 1-galanin receptor type 3 (GalR1-GalR3), are involved in the regulation of numerous physiological and disease processes, and thus represent tremendous potential in neuroscience research and novel drug lead development. One of the areas where galanin is involved is depression. Previous studies have suggested that activation of GalR2 leads to attenuation of depression-like behavior. Unfortunately, lack of in vivo usable subtype specific ligands hinders testing the role of galanin in depression mechanisms. In this article, we utilize an approach of increasing in vivo usability of peptide-based ligands, acting upon CNS. Thus, we have synthesized a series of novel systemically active galanin analogs, with modest preferential binding toward GalR2. We have shown that specific chemical modifications to the galanin backbone increase brain levels upon i.v. injection of the peptides. Several of the new peptides, similar to a common clinically used antidepressant medication imipramine, exerted antidepressant-like effect in forced swim test, a mouse model of depression, at a surprisingly low dose range (< 0.5 mg/kg). We chose one of the peptides, J18, for more thorough study, and showed its efficacy also in another mouse depression model (tail suspension test), and demonstrated that its antidepressant-like effect upon i.v. administration can be blocked by i.c.v. galanin receptor antagonist M35. The effect of the J18 was also abolished in GalR2KO animals. All this suggests that systemically administered peptide analog J18 exerts its biological effect through activation of GalR2 in the brain. The novel galanin analogs represent potential drug leads and a novel pharmaceutical intervention for depression.
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Affiliation(s)
- Indrek Saar
- Institute of Technology, University of Tartu, Tartu, Estonia; Department of Neurochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
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40
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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.
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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.
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Affiliation(s)
- Maria E Anderson
- Department of Psychology, Stony Brook University, Stony Brook, NY 11794, USA
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42
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Rovin ML, Boss-Williams KA, Alisch RS, Ritchie JC, Weinshenker D, West CH, Weiss JM. Influence of chronic administration of antidepressant drugs on mRNA for galanin, galanin receptors, and tyrosine hydroxylase in catecholaminergic and serotonergic cell-body regions in rat brain. Neuropeptides 2012; 46:81-91. [PMID: 22317959 PMCID: PMC3759228 DOI: 10.1016/j.npep.2012.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 11/11/2011] [Accepted: 01/02/2012] [Indexed: 11/19/2022]
Abstract
Activity of locus coeruleus (LC) neurons and release of the peptide galanin (GAL), which is colocalized with norepinephrine (NE) in LC neurons, has been implicated in depression and, conversely, in antidepressant action. The present study examined the influence of chronic administration (for 14days, via subcutaneously-implanted minipump) of antidepressant (AD) drugs representing three different classes (tricyclic [desipramine], selective serotonin reuptake inhibitor [SSRI] [paroxetine], and monoamine oxidase inhibitor [MAOI] [phenelzine]) on mRNA for GAL, GAL receptors (GalR1, GalR2, and GalR3), and tyrosine hydroxylase (TH), the rate-limiting enzyme for NE synthesis, in four brain regions--LC, A1/C1, dorsal raphe (DRN), and ventral tegmentum (VTA) of rats. Consistent with previous findings that chronic administration of AD drugs decreases activity of LC neurons, administration of AD drugs reduced mRNA for both GAL and TH in LC neurons. GAL and TH mRNA in LC neurons was highly correlated. AD drugs also reduced GAL and TH mRNA in A1/C1 and VTA but effects were smaller than in LC. The largest change in mRNA for GAL receptors produced by AD administration was to decrease mRNA for GalR2 receptors in the VTA region. Also, mRNA for GalR2 and GalR3 receptors was significantly (positively) correlated in all three predominantly catecholaminergic brain regions (LC, A1/C1, and VTA). Relative to these three brain regions, unique effects were seen in the DRN region, with the SSRI elevating GAL mRNA and with mRNA for GalR1 and GalR3 being highly correlated in this brain region. The findings show that chronic administration of AD drugs, which produces effective antidepressant action, results in changes in mRNA for GAL, GAL receptors, and TH in brain regions that likely participate in depression and antidepressant effects.
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Affiliation(s)
| | | | | | - James C. Ritchie
- Department of Pathology Emory University School of Medicine Atlanta, GA, USA
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43
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Abstract
Since the publication of the working draft of the human genome just over a decade ago, there have been dramatic advances in our understanding of the role genetics play in both normal human functioning as well as in disease. The identification of genes, which influence an individual's susceptibility to depression, is not only an intriguing scientific endeavour in its own right, but further, if a gene can be confidently implicated in depression, then this could shed light on the aetiological processes involved in the disease. Moreover, a genetic association with depression may identify targets for consideration in the development of novel treatments for the illness. This chapter will summarise the current research into the genetic basis of depression. A number of genes of interest have been highlighted, although a genetic variant, that is unequivocally associated with increased risk for the disease, is yet to be identified. However, technologies and methodologies are evolving rapidly, and genetic approaches have helped shape how we conceptualise depression as an illness.
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44
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Wray NR, Pergadia ML, Blackwood DHR, Penninx BWJH, Gordon SD, Nyholt DR, Ripke S, MacIntyre DJ, McGhee KA, Maclean AW, Smit JH, Hottenga JJ, Willemsen G, Middeldorp CM, de Geus EJC, Lewis CM, McGuffin P, Hickie IB, van den Oord EJCG, Liu JZ, Macgregor S, McEvoy BP, Byrne EM, Medland SE, Statham DJ, Henders AK, Heath AC, Montgomery GW, Martin NG, Boomsma DI, Madden PAF, Sullivan PF. Genome-wide association study of major depressive disorder: new results, meta-analysis, and lessons learned. Mol Psychiatry 2012; 17:36-48. [PMID: 21042317 PMCID: PMC3252611 DOI: 10.1038/mp.2010.109] [Citation(s) in RCA: 324] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 09/12/2010] [Accepted: 09/27/2010] [Indexed: 12/14/2022]
Abstract
Major depressive disorder (MDD) is a common complex disorder with a partly genetic etiology. We conducted a genome-wide association study of the MDD2000+ sample (2431 cases, 3673 screened controls and >1 M imputed single-nucleotide polymorphisms (SNPs)). No SNPs achieved genome-wide significance either in the MDD2000+ study, or in meta-analysis with two other studies totaling 5763 cases and 6901 controls. These results imply that common variants of intermediate or large effect do not have main effects in the genetic architecture of MDD. Suggestive but notable results were (a) gene-based tests suggesting roles for adenylate cyclase 3 (ADCY3, 2p23.3) and galanin (GAL, 11q13.3); published functional evidence relates both of these to MDD and serotonergic signaling; (b) support for the bipolar disorder risk variant SNP rs1006737 in CACNA1C (P=0.020, odds ratio=1.10); and (c) lack of support for rs2251219, a SNP identified in a meta-analysis of affective disorder studies (P=0.51). We estimate that sample sizes 1.8- to 2.4-fold greater are needed for association studies of MDD compared with those for schizophrenia to detect variants that explain the same proportion of total variance in liability. Larger study cohorts characterized for genetic and environmental risk factors accumulated prospectively are likely to be needed to dissect more fully the etiology of MDD.
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Affiliation(s)
- N R Wray
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - M L Pergadia
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - D H R Blackwood
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - B W J H Penninx
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - S D Gordon
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - D R Nyholt
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - S Ripke
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - D J MacIntyre
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - K A McGhee
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - A W Maclean
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - J H Smit
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - J J Hottenga
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - G Willemsen
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - C M Middeldorp
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - E J C de Geus
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - C M Lewis
- Department of Medical and Molecular Genetics, King's College London, MRC SGDP Centre, Institute of Psychiatry, London, UK
| | - P McGuffin
- Department of Medical and Molecular Genetics, King's College London, MRC SGDP Centre, Institute of Psychiatry, London, UK
| | - I B Hickie
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, NSW, Australia
| | - E J C G van den Oord
- Center for Biomarker Research and Personalized Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - J Z Liu
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - S Macgregor
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - B P McEvoy
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - E M Byrne
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - S E Medland
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - D J Statham
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - A K Henders
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - A C Heath
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - G W Montgomery
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - N G Martin
- Genetic Epidemiology, Molecular Epidemiology, Psychiatric Genetics and Queensland Statistical Genetics Laboratories, Queensland Institute of Medical Research, Brisbane, QLD, Australia
| | - D I Boomsma
- Department of Biological Psychology and Medical Center, VU University, Amsterdam, The Netherlands
| | - P A F Madden
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - P F Sullivan
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
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Sagi VN, Liu T, Lu X, Bartfai T, Roberts E. Synthesis and biological evaluation of novel pyrimidine derivatives as sub-micromolar affinity ligands of GalR2. Bioorg Med Chem Lett 2011; 21:7210-5. [PMID: 22018787 DOI: 10.1016/j.bmcl.2011.09.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/07/2011] [Accepted: 09/12/2011] [Indexed: 01/03/2023]
Abstract
GalR1 and GalR2 represent unique pharmacological targets for treatment of seizures and epilepsy. A novel series of 2,4,6-triaminopyrimidine derivatives were synthesized and found to have sub-micromolar affinity for GalR2. Optimization of a series of 2,4,6-triaminopyrimidines led to the discovery of several analogs with IC50 values ranging from 0.3 to 1 μM.
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Affiliation(s)
- Vasudeva Naidu Sagi
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, United States
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46
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Le Maître TW, Xia S, Le Maitre E, Dun XP, Lu J, Theodorsson E, Ogren SO, Hökfelt T, Xu ZQD. Galanin receptor 2 overexpressing mice display an antidepressive-like phenotype: possible involvement of the subiculum. Neuroscience 2011; 190:270-88. [PMID: 21672612 DOI: 10.1016/j.neuroscience.2011.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 04/21/2011] [Accepted: 05/04/2011] [Indexed: 01/13/2023]
Abstract
The behavioral phenotype of a transgenic mouse overexpressing a galanin receptor 2 (GalR2)-enhanced, green fluorescent protein (EGFP)-construct under the platelet-derived growth factor-B promoter, and of controls, was assessed in various behavioral tests, such as the Porsolt forced swim test, as well as the open field, elevated plus maze and passive avoidance tests. In addition, the distribution of GalR2-EGFP expressing cell bodies and processes was studied in the brain of these mice using histochemical methods. Three age groups of the transgenic mice demonstrated decreased levels of immobility in the forced swim test, indicative of antidepressive-like behavior and/or increased stress resistance. Anxiety-like behaviors, measured in two different tests, did not differ between the GalR2-overexpressing and the wild-type mice, nor did motor activity levels, emotional learning or memory behaviors. High levels of GalR2 mRNA and protein expression were observed in the presubiculum, subiculum, cingulate cortex, retrosplenial granular and agranular cortices, subregions of prefrontal cortex, and the olfactory bulb, regions which are directly or indirectly implicated in depression-like behavior. These results may contribute to the understanding of the pathophysiology of major depressive disorder and the role of GalR2 in the regulation of mood, and suggest a potential therapeutic effect by targeting the GalR2 for treatment of depressive disorders.
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Affiliation(s)
- T Wardi Le Maître
- Department of Neuroscience, Karolinska Institutet, Retzius Väg 8, S-17177 Stockholm, Sweden.
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47
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Effects of chronic antidepressant drug administration and electroconvulsive shock on activity of dopaminergic neurons in the ventral tegmentum. Int J Neuropsychopharmacol 2011; 14:201-10. [PMID: 20482941 PMCID: PMC3032823 DOI: 10.1017/s1461145710000489] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increasing attention is now focused on reduced dopaminergic neurotransmission in the forebrain as participating in depression. The present paper assessed whether effective antidepressant (AD) treatments might counteract, or compensate for, such a change by altering the neuronal activity of dopaminergic neurons in the ventral tegmental area (VTA-DA neurons), the cell bodies of the mesocorticolimbic dopaminergic system. Eight AD drugs or vehicle were administered to rats for 14 d via subcutaneously implanted minipumps, at which time single-unit electrophysiological activity of VTA-DA neurons was recorded under anaesthesia. Further, animals received a series of five electroconvulsive shocks (ECS) or control procedures, after which VTA-DA activity was measured either 3 d or 5 d after the last ECS. Results showed that the chronic administration of all AD drugs tested except for the monoamine oxidase inhibitor increased the spontaneous firing rate of VTA-DA neurons, while effects on 'burst' firing activity were found to be considerably less notable or consistent. ECS increased both spontaneous firing rate and burst firing of VTA-DA neurons. It is suggested that the effects observed are consistent with reports of increased dopamine release in regions to which VTA neurons project after effective AD treatment. However, it is further suggested that changes in VTA-DA neuronal activity in response to AD treatment should be most appropriately assessed under conditions associated with depression, such as stressful conditions.
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Razzoli M, Andreoli M, Michielin F, Quarta D, Sokal DM. Increased phasic activity of VTA dopamine neurons in mice 3 weeks after repeated social defeat. Behav Brain Res 2010; 218:253-7. [PMID: 21129410 DOI: 10.1016/j.bbr.2010.11.050] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/19/2010] [Accepted: 11/23/2010] [Indexed: 01/09/2023]
Abstract
Social defeat is an ethologically relevant stress inducing neuroadaptive changes in the mesocorticolimbic dopaminergic system. Three weeks after 10 days of daily defeat salient behaviors and in vivo dopamine (DA) neuron firing were evaluated in mice. Prior defeat induced social avoidance and hyperphagia and increased ventral tegmental area (VTA) DA neuron bursting activity. These data extend previous studies and suggest that increased phasic DA neuron firing in the VTA could be considered amongst the features defining the lasting imprint of social defeat stress.
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Affiliation(s)
- Maria Razzoli
- Neurosciences CEDD, GlaxoSmithKline Medicine Research Centre, Via Fleming 4, Verona, Italy.
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Fu W, Le Maître E, Fabre V, Bernard JF, David Xu ZQ, Hökfelt T. Chemical neuroanatomy of the dorsal raphe nucleus and adjacent structures of the mouse brain. J Comp Neurol 2010; 518:3464-94. [PMID: 20589909 DOI: 10.1002/cne.22407] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Serotonin neurons play a major role in many normal and pathological brain functions. In the rat these neurons have a varying number of cotransmitters, including neuropeptides. Here we studied, with histochemical techniques, the relation between serotonin, some other small-molecule transmitters, and a number of neuropeptides in the dorsal raphe nucleus (DRN) and the adjacent ventral periaqueductal gray (vPAG) of mouse, an important question being to establish possible differences from rat. Even if similarly distributed, the serotonin neurons in mouse lacked the extensive coexpression of nitric oxide synthase and galanin seen in rat. Although partly overlapping in the vPAG, no evidence was obtained for the coexistence of serotonin with dopamine, substance P, cholecystokinin, enkephalin, somatostatin, neurotensin, dynorphin, thyrotropin-releasing hormone, or corticotropin-releasing hormone. However, some serotonin neurons expressed the gamma-aminobutyric acid (GABA)-synthesizing enzyme glutamic acid decarboxylase (GAD). Work in other laboratories suggests that, as in rat, serotonin neurons in the mouse midline DRN express the vesicular glutamate transporter 3, presumably releasing glutamate. Our study also shows that many of the neuropeptides studied (substance P, galanin, neurotensin, dynorphin, and corticotropin-releasing factor) are present in nerve terminal networks of varying densities close to the serotonin neurons, and therefore may directly or indirectly influence these cells. The apparently low numbers of coexisting messengers in mouse serotonin neurons, compared to rat, indicate considerable species differences with regard to the chemical neuronatomy of the DRN. Thus, extrapolation of DRN physiology, and possibly pathology, from rat to mouse, and even human, should be made with caution.
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Affiliation(s)
- Wenyu Fu
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
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GalR2-positive allosteric modulator exhibits anticonvulsant effects in animal models. Proc Natl Acad Sci U S A 2010; 107:15229-34. [PMID: 20660766 DOI: 10.1073/pnas.1008986107] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Galanin receptors type 1 (GalR1) and/or type 2 (GalR2) represent unique pharmacological targets for treatment of seizures and epilepsy. Previous studies have shown that the endogenous peptide ligand galanin exerts powerful anticonvulsant effect through activation of these two G protein-coupled receptors, which are highly expressed in the temporal lobe of rodent brain. Here we report the characterization of a putative GalR2-positive allosteric modulator CYM2503. CYM2503 potentiated the galanin-stimulated IP1 accumulation in HEK293 cells stably expressing GalR2 receptor, whereas it exhibited no detectable affinity for the (125)I galanin-binding site of GalR2 receptor, an effect consistent with that of a positive allosteric modulator. In the rat Li-pilocarpine status epilepticus model, CYM2503, injected intraperitoneally, increased the latency to first electrographic seizure and the latency to first stage 3 behavioral seizure, decreased the latency to the establishment of status epilepticus, and dramatically decreased the mortality. In a Li-pilocarpine seizure model in mice, CYM2503 increased the latency to first electrographic seizure and decreased the total time in seizure. CYM2503 also attenuated electroshock-induced seizures in mice. Thus, CYM2503 provides a starting point for the development of anticonvulsant therapy using the galanin R2 receptor as target.
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