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Neuroanatomical characterization of the G protein-coupled receptor activity evoked by galanin-related ligands. J Chem Neuroanat 2023; 128:102226. [PMID: 36566994 DOI: 10.1016/j.jchemneu.2022.102226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Galanin neuropeptide is distributed throughout the mammalian nervous system modulating a plethora of diverse physiological functions, including nociception, cognition and neuroendocrine regulation. The regulation of the galaninergic system is an interesting approach for the treatment of different diseases associated to those systems. Nevertheless, the pharmacological selectivity and activities of some galanin receptor (GalR) ligands are still in discussion and seem to depend on the dose, the receptor subtype and the second messengers to which they are coupled at different brain areas. The activity of different GalR ligands on Gi/o proteins, was evaluated by the guanosine 5'-(γ-[35S]thio)triphosphate ([35S]GTPγS) autoradiography in vitro assay applied to rat brain tissue slices in the presence of galanin, M15, M35, M40, gal(2-11) or galnon. The enhancement of the [35S]GTPγS binding induced by the chimerical peptides M15, M35 and M40 was similar to that produced by Gal in those brain areas showing the highest stimulations, such as dorsal part of the olfactory nucleus and ventral subiculum. In contrast to these peptides, using gal(2-11) no effect was measured on Gi/o protein coupling in areas of the rat brain with high GalR1 density such as posterior hypothalamic nucleus and amygdala, indicating low selectivity for GalR1 receptors. The effects evoked by the non-peptide ligand, galnon, were different from those induced by galanin, behaving as agonist or antagonist depending on the brain area, but the stimulations were always blocked by M35. Thus, the activity of most used GalR ligands on Gi/o protein mediated signalling is complex and depends on the brain area. More selective and potent GalR ligands are necessary to develop new treatments aimed to modulate the galaninergic system.
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2
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An K, Cui Y, Zhong X, Li K, Zhang J, Liu H, Wen Z. Immortalized Bone Mesenchymal Stromal Cells With Inducible Galanin Expression Produce Controllable Pain Relief in Neuropathic Rats. Cell Transplant 2022; 31:9636897221103861. [PMID: 35726855 PMCID: PMC9218486 DOI: 10.1177/09636897221103861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Management of chronic pain is one of the most difficult problems in modern practice. Grafted human telomerase reverse transcriptase–immortalized bone marrow mesenchymal stromal cells (hTERT-BMSCs) with inducible galanin (GAL) expression have been considered to be a potentially safe and controllable approach for the alleviation of chronic pain. Therefore, in this study, we aimed to assess the feasibility of hTERT-BMSCs/Tet-on/GAL cells secreting GAL under the transcriptional control of doxycycline (Dox) for controllable pain relief. After transplanted into the subarachnoid space of neuropathic rats induced by spared nerve injury of sciatic nerve, their analgesic actions were investigated by behavioral tests. The results showed that the pain-related behaviors, mechanical allodynia, and thermal hyperalgesia were significantly alleviated during 1 to 7 weeks after grafts of hTERT-BMSCs/Tet-on/GAL cells without motor incoordination. Importantly, these effects could be reversed by GAL receptor antagonist M35 and regulated by Dox induction as compared with control. Moreover, the GAL level in cerebrospinal fluid and spinal GAL receptor 1 (GalR1) expression were correlated with Dox administration, but not GAL receptor 2 (GalR2). Meanwhile, spinal protein kinase Mζ (PKMζ) expression was also inhibited significantly. Taken together, these data suggest that inducible release of GAL from transplanted cells was able to produce controllable pain relief in neuropathic rats via inhibiting the PKMζ activation and activating its GalR1 rather than GalR2. This provides a promising step toward a novel stem cell–based strategy for pain therapy.
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Affiliation(s)
- Ke An
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Yingpeng Cui
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Xiaolong Zhong
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Department of Anesthesiology, Guangzhou First people's Hospital, Guangzhou, China
| | - Kunhe Li
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Jinjun Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Huiping Liu
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.,Department of Anesthesiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Zhishuang Wen
- Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
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3
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Miranda CO, Hegedüs K, Wildner H, Zeilhofer HU, Antal M. Morphological and neurochemical characterization of glycinergic neurons in laminae I-IV of the mouse spinal dorsal horn. J Comp Neurol 2021; 530:607-626. [PMID: 34382691 DOI: 10.1002/cne.25232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 08/04/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022]
Abstract
A growing body of experimental evidence shows that glycinergic inhibition plays vital roles in spinal pain processing. In spite of this, however, our knowledge about the morphology, neurochemical characteristics, and synaptic relations of glycinergic neurons in the spinal dorsal horn is very limited. The lack of this knowledge makes our understanding about the specific contribution of glycinergic neurons to spinal pain processing quite vague. Here we investigated the morphology and neurochemical characteristics of glycinergic neurons in laminae I-IV of the spinal dorsal horn using a GlyT2::CreERT2-tdTomato transgenic mouse line. Confirming previous reports, we show that glycinergic neurons are sparsely distributed in laminae I-II, but their densities are much higher in lamina III and especially in lamina IV. First in the literature, we provide experimental evidence indicating that in addition to neurons in which glycine colocalizes with GABA, there are glycinergic neurons in laminae I-II that do not express GABA and can thus be referred to as glycine-only neurons. According to the shape and size of cell bodies and dendritic morphology, we divided the tdTomato-labeled glycinergic neurons into three and six morphological groups in laminae I-II and laminae III-IV, respectively. We also demonstrate that most of the glycinergic neurons co-express neuronal nitric oxide synthase, parvalbumin, the receptor tyrosine kinase RET, and the retinoic acid-related orphan nuclear receptor β (RORβ), but there might be others that need further neurochemical characterization. The present findings may foster our understanding about the contribution of glycinergic inhibition to spinal pain processing.
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Affiliation(s)
- Camila Oliveira Miranda
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Hegedüs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Miklós Antal
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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4
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Liu F, Yajima T, Wang M, Shen JF, Ichikawa H, Sato T. Effects of trigeminal nerve injury on the expression of galanin and its receptors in the rat trigeminal ganglion. Neuropeptides 2020; 84:102098. [PMID: 33069139 DOI: 10.1016/j.npep.2020.102098] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 11/24/2022]
Abstract
In the spinal nervous system, the expression of galanin (GAL) and galanin receptors (GALRs) that play important roles in the transmission and modulation of nociceptive information can be affected by nerve injury. However, in the trigeminal nervous system, the effects of trigeminal nerve injury on the expression of GAL are controversy in the previous studies. Besides, little is known about the effects of trigeminal nerve injury on the expression of GALRs. In the present study, the effects of trigeminal nerve injury on the expression of GAL and GALRs in the rat trigeminal ganglion (TG) were investigated by using quantitative real-time reverse transcription-polymerase chain reaction and immunohistochemistry. To identify the nerve-injured and nerve-uninjured TG neurons, activating transcription factor 3 (ATF3, the nerve-injured neuron marker) was stained by immunofluorescence. The levels of GAL mRNA in the rostral half and caudal half of the TG dramatically increased after transection of infraorbital nerve (ION) and inferior alveolar nerve (IAN), respectively. Immunohistochemical labeling of GAL and ATF3 revealed that GAL level was elevated in both injured and adjacent uninjured small and medium-sized TG neurons after ION/IAN transection. In addition, the levels of GAL2R-like immunoreactivity were reduced in both injured and adjacent uninjured TG neurons after ION/IAN transection, while levels of GAL1R and GAL3R-like immunoreactivity remained unchanged. Furthermore, the number of small to medium-sized TG neurons co-expressing GAL- and GAL1R/GAL2R/GAL3R-like immunoreactivity was significantly increased after ION/IAN transection. In line with previous studies in other spinal neuron systems, these results suggest that GAL and GALRs play functional roles in orofacial neuropathic pain and trigeminal nerve regeneration after trigeminal nerve injury.
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Affiliation(s)
- Fei Liu
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo machi, Sendai 980-8575, Japan; State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department II of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province 610041, China.
| | - Takehiro Yajima
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo machi, Sendai 980-8575, Japan
| | - Min Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department II of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province 610041, China
| | - Jie-Fei Shen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department II of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan Province 610041, China
| | - Hiroyuki Ichikawa
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo machi, Sendai 980-8575, Japan
| | - Tadasu Sato
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo machi, Sendai 980-8575, Japan
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Cellular Mechanisms for Antinociception Produced by Oxytocin and Orexins in the Rat Spinal Lamina II-Comparison with Those of Other Endogenous Pain Modulators. Pharmaceuticals (Basel) 2019; 12:ph12030136. [PMID: 31527474 PMCID: PMC6789548 DOI: 10.3390/ph12030136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/31/2019] [Accepted: 09/12/2019] [Indexed: 01/23/2023] Open
Abstract
Much evidence indicates that hypothalamus-derived neuropeptides, oxytocin, orexins A and B, inhibit nociceptive transmission in the rat spinal dorsal horn. In order to unveil cellular mechanisms for this antinociception, the effects of the neuropeptides on synaptic transmission were examined in spinal lamina II neurons that play a crucial role in antinociception produced by various analgesics by using the whole-cell patch-clamp technique and adult rat spinal cord slices. Oxytocin had no effect on glutamatergic excitatory transmission while producing a membrane depolarization, γ-aminobutyric acid (GABA)-ergic and glycinergic spontaneous inhibitory transmission enhancement. On the other hand, orexins A and B produced a membrane depolarization and/or a presynaptic spontaneous excitatory transmission enhancement. Like oxytocin, orexin A enhanced both GABAergic and glycinergic transmission, whereas orexin B facilitated glycinergic but not GABAergic transmission. These inhibitory transmission enhancements were due to action potential production. Oxytocin, orexins A and B activities were mediated by oxytocin, orexin-1 and orexin-2 receptors, respectively. This review article will mention cellular mechanisms for antinociception produced by oxytocin, orexins A and B, and discuss similarity and difference in antinociceptive mechanisms among the hypothalamic neuropeptides and other endogenous pain modulators (opioids, nociceptin, adenosine, adenosine 5’-triphosphate (ATP), noradrenaline, serotonin, dopamine, somatostatin, cannabinoids, galanin, substance P, bradykinin, neuropeptide Y and acetylcholine) exhibiting a change in membrane potential, excitatory or inhibitory transmission in the spinal lamina II neurons.
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6
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Kozyrev N, Coolen LM. Activation of galanin and cholecystokinin receptors in the lumbosacral spinal cord is required for ejaculation in male rats. Eur J Neurosci 2017; 45:846-858. [DOI: 10.1111/ejn.13515] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/15/2016] [Accepted: 12/17/2016] [Indexed: 01/23/2023]
Affiliation(s)
- Natalie Kozyrev
- Department of Anatomy and Cell Biology; Western University; London ON Canada
- Department of Physiology; University of Michigan; Ann Arbor MI USA
| | - Lique M. Coolen
- Department of Anatomy and Cell Biology; Western University; London ON Canada
- Department of Physiology; University of Michigan; Ann Arbor MI USA
- Department of Neurobiology and Anatomical Sciences; University of Mississippi Medical Center; Jackson MS USA
- Department of Physiology and Biophysics; University of Mississippi Medical Center; 2500 North State Street Jackson MS 39216 USA
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Todd AJ. Identifying functional populations among the interneurons in laminae I-III of the spinal dorsal horn. Mol Pain 2017; 13:1744806917693003. [PMID: 28326935 PMCID: PMC5315367 DOI: 10.1177/1744806917693003] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/15/2022] Open
Abstract
The spinal dorsal horn receives input from primary afferent axons, which terminate in a modality-specific fashion in different laminae. The incoming somatosensory information is processed through complex synaptic circuits involving excitatory and inhibitory interneurons, before being transmitted to the brain via projection neurons for conscious perception. The dorsal horn is important, firstly because changes in this region contribute to chronic pain states, and secondly because it contains potential targets for the development of new treatments for pain. However, at present, we have only a limited understanding of the neuronal circuitry within this region, and this is largely because of the difficulty in defining functional populations among the excitatory and inhibitory interneurons. The recent discovery of specific neurochemically defined interneuron populations, together with the development of molecular genetic techniques for altering neuronal function in vivo, are resulting in a dramatic improvement in our understanding of somatosensory processing at the spinal level.
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Affiliation(s)
- Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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8
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Bu L, Chang X, Cheng X, Yao Q, Su B, Sheng C, Qu S. Activated central galanin type 1 receptor alleviated insulin resistance in diabetic rat muscle. J Neurosci Res 2016; 94:947-55. [PMID: 27410235 DOI: 10.1002/jnr.23775] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 01/14/2023]
Affiliation(s)
- Le Bu
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Xusheng Chang
- Department of General Surgery; Yancheng City First People's Hospital; Yancheng City Jiangsu People's Republic of China
| | - Xiaoyun Cheng
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Qian Yao
- Key Laboratory of Sichuan Province of Medicinal Chemistry; Chengdu University; Chengdu People's Republic of China
| | - Bin Su
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Chunjun Sheng
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
| | - Shen Qu
- Department of Endocrinology; Shanghai 10th People's Hospital, Tongji University School of Medicine; Shanghai People's Republic of China
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9
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Lyu C, Mulder J, Barde S, Sahlholm K, Zeberg H, Nilsson J, Århem P, Hökfelt T, Fried K, Shi TJS. G protein-gated inwardly rectifying potassium channel subunits 1 and 2 are down-regulated in rat dorsal root ganglion neurons and spinal cord after peripheral axotomy. Mol Pain 2015. [PMID: 26199148 PMCID: PMC4511542 DOI: 10.1186/s12990-015-0044-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background Increased nociceptive neuronal excitability underlies chronic pain conditions. Various ion channels, including sodium, calcium and potassium channels have pivotal roles in the control of neuronal excitability. The members of the family of G protein-gated inwardly rectifying potassium (GIRK) channels, GIRK1–4, have been implicated in modulating excitability. Here, we investigated the expression and distribution of GIRK1 and GIRK2 in normal and injured dorsal root ganglia (DRGs) and spinal cord of rats. Results We found that ~70% of the DRG neurons expressed GIRK1, while only <10% expressed GIRK2. The neurochemical profiles of GIRK1- and GIRK2-immunoreactive neurons were characterized using the neuronal markers calcitonin gene-related peptide, isolectin-B4 and neurofilament-200, and the calcium-binding proteins calbindin D28k, calretinin, parvalbumin and secretagogin. Both GIRK subunits were expressed in DRG neurons with nociceptive characteristics. However, while GIRK1 was widely expressed in several sensory neuronal subtypes, GIRK2 was detected mainly in a group of small C-fiber neurons. In the spinal dorsal horn, GIRK1- and -2-positive cell bodies and processes were mainly observed in lamina II, but also in superficial and deeper layers. Abundant GIRK1-, but not GIRK2-like immunoreactivity, was found in the ventral horn (laminae VI–X). Fourteen days after axotomy, GIRK1 and GIRK2 were down-regulated in DRG neurons at the mRNA and protein levels. Both after axotomy and rhizotomy there was a reduction of GIRK1- and -2-positive processes in the dorsal horn, suggesting a presynaptic localization of these potassium channels. Furthermore, nerve ligation caused accumulation of both subunits on both sides of the lesion, providing evidence for anterograde and retrograde fast axonal transport. Conclusions Our data support the hypothesis that reduced GIRK function is associated with increased neuronal excitability and causes sensory disturbances in post-injury conditions, including neuropathic pain. Electronic supplementary material The online version of this article (doi:10.1186/s12990-015-0044-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chuang Lyu
- School of Life Science and Technology, Harbin Institute of Technology, 150001, Harbin, China. .,Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Jan Mulder
- Department of Neuroscience, Science for Life Laboratory, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Kristoffer Sahlholm
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Hugo Zeberg
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Johanna Nilsson
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Peter Århem
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Kaj Fried
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Tie-Jun Sten Shi
- School of Life Science and Technology, Harbin Institute of Technology, 150001, Harbin, China. .,Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
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10
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Lang R, Gundlach AL, Holmes FE, Hobson SA, Wynick D, Hökfelt T, Kofler B. Physiology, signaling, and pharmacology of galanin peptides and receptors: three decades of emerging diversity. Pharmacol Rev 2015; 67:118-75. [PMID: 25428932 DOI: 10.1124/pr.112.006536] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Galanin was first identified 30 years ago as a "classic neuropeptide," with actions primarily as a modulator of neurotransmission in the brain and peripheral nervous system. Other structurally-related peptides-galanin-like peptide and alarin-with diverse biologic actions in brain and other tissues have since been identified, although, unlike galanin, their cognate receptors are currently unknown. Over the last two decades, in addition to many neuronal actions, a number of nonneuronal actions of galanin and other galanin family peptides have been described. These include actions associated with neural stem cells, nonneuronal cells in the brain such as glia, endocrine functions, effects on metabolism, energy homeostasis, and paracrine effects in bone. Substantial new data also indicate an emerging role for galanin in innate immunity, inflammation, and cancer. Galanin has been shown to regulate its numerous physiologic and pathophysiological processes through interactions with three G protein-coupled receptors, GAL1, GAL2, and GAL3, and signaling via multiple transduction pathways, including inhibition of cAMP/PKA (GAL1, GAL3) and stimulation of phospholipase C (GAL2). In this review, we emphasize the importance of novel galanin receptor-specific agonists and antagonists. Also, other approaches, including new transgenic mouse lines (such as a recently characterized GAL3 knockout mouse) represent, in combination with viral-based techniques, critical tools required to better evaluate galanin system physiology. These in turn will help identify potential targets of the galanin/galanin-receptor systems in a diverse range of human diseases, including pain, mood disorders, epilepsy, neurodegenerative conditions, diabetes, and cancer.
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Affiliation(s)
- Roland Lang
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Andrew L Gundlach
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Fiona E Holmes
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Sally A Hobson
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - David Wynick
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Tomas Hökfelt
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
| | - Barbara Kofler
- Department of Dermatology (R.L.) and Laura Bassi Centre of Expertise, Department of Pediatrics (B.K.), Paracelsus Private Medical University, Salzburg, Austria; The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia (A.L.G.); Schools of Physiology and Pharmacology and Clinical Sciences, Bristol University, Bristol, United Kingdom (F.E.H., S.A.H., D.W.); and Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (T.H.)
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11
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Diabetic peripheral neuropathy: Current perspective and future directions. Pharmacol Res 2014; 80:21-35. [DOI: 10.1016/j.phrs.2013.12.005] [Citation(s) in RCA: 201] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/26/2013] [Accepted: 12/16/2013] [Indexed: 01/17/2023]
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12
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Chandler DJ, Lamperski CS, Waterhouse BD. Identification and distribution of projections from monoaminergic and cholinergic nuclei to functionally differentiated subregions of prefrontal cortex. Brain Res 2013; 1522:38-58. [PMID: 23665053 DOI: 10.1016/j.brainres.2013.04.057] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/25/2013] [Accepted: 04/30/2013] [Indexed: 12/21/2022]
Abstract
The prefrontal cortex (PFC) is implicated in a variety of cognitive and executive functions and is composed of several distinct networks, including anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC), and orbitofrontal cortex (OFC). These regions serve dissociable cognitive functions, and are heavily innervated by acetylcholine, dopamine, serotonin and norepinephrine systems. In this study, fluorescently labeled retrograde tracers were injected into the ACC, mPFC, and OFC, and labeled cells were identified in the nucleus basalis (NB), ventral tegmental area (VTA), dorsal raphe nucleus (DRN) and locus coeruleus (LC). DRN and LC showed similar distributions of retrogradely labeled neurons such that most were single labeled and the largest population projected to mPFC. VTA showed a slightly greater proportion of double and triple labeled neurons, with the largest population projecting to OFC. NB, on the other hand, showed mostly double and triple labeled neurons projecting to multiple subregions. Therefore, subsets of VTA, DRN and LC neurons may be capable of modulating individual prefrontal subregions independently, whereas NB cells may exert a more unified influence on the three areas simultaneously. These findings emphasize the unique aspects of the cholinergic and monoaminergic projections to functionally and anatomically distinct subregions of PFC.
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Affiliation(s)
- Daniel J Chandler
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19128, United States
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Tlx1/3 and Ptf1a control the expression of distinct sets of transmitter and peptide receptor genes in the developing dorsal spinal cord. J Neurosci 2012; 32:8509-20. [PMID: 22723691 DOI: 10.1523/jneurosci.6301-11.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Establishing the pattern of expression of transmitters and peptides as well as their receptors in different neuronal types is crucial for understanding the circuitry in various regions of the brain. Previous studies have demonstrated that the transmitter and peptide phenotypes in mouse dorsal spinal cord neurons are determined by the transcription factors Tlx1/3 and Ptf1a. Here we show that these transcription factors also determine the expression of two distinct sets of transmitter and peptide receptor genes in this region. We have screened the expression of 78 receptor genes in the spinal dorsal horn by in situ hybridization. We found that receptor genes Gabra1, Gabra5, Gabrb2, Gria3, Grin3a, Grin3b, Galr1, and Npy1r were preferentially expressed in Tlx3-expressing glutamatergic neurons and their derivatives, and deletion of Tlx1 and Tlx3 resulted in the loss of expression of these receptor genes. Furthermore, we obtained genetic evidence that Tlx3 uses distinct pathways to control the expression of receptor genes. We also found that receptor genes Grm3, Grm4, Grm5, Grik1, Grik2, Grik3, and Sstr2 were mainly expressed in Pax2-expressing GABAergic neurons in the spinal dorsal horn, and their expression in this region was abolished or markedly reduced in Ptf1a and Pax2 deletion mutant mice. Together, our studies indicate that Tlx1/3 and Ptf1a, the key transcription factors for fate determination of glutamatergic and GABAergic neurons in the dorsal spinal cord, are also responsible for controlling the expression of two distinct sets of transmitter and peptide receptor genes.
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Effects of exogenous galanin on neuropathic pain state and change of galanin and its receptors in DRG and SDH after sciatic nerve-pinch injury in rat. PLoS One 2012; 7:e37621. [PMID: 22624057 PMCID: PMC3356287 DOI: 10.1371/journal.pone.0037621] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/22/2012] [Indexed: 02/06/2023] Open
Abstract
A large number of neuroanatomical, neurophysiologic, and neurochemical mechanisms are thought to contribute to the development and maintenance of neuropathic pain. However, mechanisms responsible for neuropathic pain have not been completely delineated. It has been demonstrated that neuropeptide galanin (Gal) is upregulated after injury in the dorsal root ganglion (DRG) and spinal dorsal horn (SDH) where it plays a predominantly antinociceptive role. In the present study, sciatic nerve-pinch injury rat model was used to determine the effects of exogenous Gal on the expression of the Gal and its receptors (GalR1, GalR2) in DRG and SDH, the alterations of pain behavior, nerve conduction velocity (NCV) and morphology of sciatic nerve. The results showed that exogenous Gal had antinociceptive effects in this nerve-pinch injury induced neuropathic pain animal model. It is very interesting that Gal, GalR1 and GalR2 change their expression greatly in DRG and SDH after nerve injury and intrathecal injection of exougenous Gal. Morphological investigation displays a serious damage after nerve-pinch injury and an amendatory regeneration after exogenous Gal treatment. These findings imply that Gal, via activation of GalR1 and/or GalR2, may have neuroprotective effects in reducing neuropathic pain behaviors and improving nerve regeneration after nerve injury.
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Bochorishvili G, Stornetta RL, Coates MB, Guyenet PG. Pre-Bötzinger complex receives glutamatergic innervation from galaninergic and other retrotrapezoid nucleus neurons. J Comp Neurol 2012; 520:1047-61. [PMID: 21935944 PMCID: PMC3925347 DOI: 10.1002/cne.22769] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The retrotrapezoid nucleus (RTN) contains CO(2) -responsive neurons that regulate breathing frequency and amplitude. These neurons (RTN-Phox2b neurons) contain the transcription factor Phox2b, vesicular glutamate transporter 2 (VGLUT2) mRNA, and a subset contains preprogalanin mRNA. We wished to determine whether the terminals of RTN-Phox2b neurons contain galanin and VGLUT2 proteins, to identify the specific projections of the galaninergic subset, to test whether RTN-Phox2b neurons contact neurons in the pre-Bötzinger complex, and to identify the ultrastructure of these synapses. The axonal projections of RTN-Phox2b neurons were traced by using biotinylated dextran amine (BDA), and many BDA-ir boutons were found to contain galanin immunoreactivity. RTN galaninergic neurons had ipsilateral projections that were identical with those of this nucleus at large: the ventral respiratory column, the caudolateral nucleus of the solitary tract, and the pontine Kölliker-Fuse, intertrigeminal region, and lateral parabrachial nucleus. For ultrastructural studies, RTN-Phox2b neurons (galaninergic and others) were transfected with a lentiviral vector that expresses mCherry almost exclusively in Phox2b-ir neurons. After spinal cord injections of a catecholamine neuron-selective toxin, there was a depletion of C1 neurons in the RTN area; thus it was determined that the mCherry-positive terminals located in the pre-Bötzinger complex originated almost exclusively from the RTN-Phox2b (non-C1) neurons. These terminals were generally VGLUT2-immunoreactive and formed numerous close appositions with neurokinin-1 receptor-ir pre-Bötzinger complex neurons. Their boutons (n = 48) formed asymmetric synapses filled with small clear vesicles. In summary, RTN-Phox2b neurons, including the galaninergic subset, selectively innervate the respiratory pattern generator plus a portion of the dorsolateral pons. RTN-Phox2b neurons establish classic excitatory glutamatergic synapses with pre-Bötzinger complex neurons presumed to generate the respiratory rhythm.
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Affiliation(s)
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Melissa B. Coates
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
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Xu X, Liu Z, Liu H, Yang X, Li Z. The effects of galanin on neuropathic pain in streptozotocin-induced diabetic rats. Eur J Pharmacol 2012; 680:28-33. [DOI: 10.1016/j.ejphar.2012.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 01/07/2012] [Accepted: 01/13/2012] [Indexed: 01/20/2023]
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17
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Peripheral galanin receptor 2 as a target for the modulation of pain. PAIN RESEARCH AND TREATMENT 2012; 2012:545386. [PMID: 22315681 PMCID: PMC3270467 DOI: 10.1155/2012/545386] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 10/19/2011] [Indexed: 11/18/2022]
Abstract
The neuropeptide galanin is widely expressed in the nervous system and has an important role in nociception. It has been shown that galanin can facilitate and inhibit nociception in a dose-dependent manner, principally through the central nervous system, with enhanced antinociceptive actions after nerve injury. However, following nerve injury, expression of galanin within the peripheral nervous system is dramatically increased up to 120-fold. Despite this striking increase in the peripheral nervous system, few studies have investigated the role that galanin plays in modulating nociception at the primary afferent nociceptor. Here, we summarise the recent work supporting the role of peripherally expressed galanin with particular reference to the dual actions of the galanin receptor 2 in neuropathic pain highlighting this as a potential target analgesic.
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Lemons LL, Wiley RG. Galanin receptor-expressing dorsal horn neurons: role in nociception. Neuropeptides 2011; 45:377-83. [PMID: 21880366 DOI: 10.1016/j.npep.2011.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 07/31/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022]
Abstract
Galanin, along with enkephalins and neuropeptide Y, has been hypothesized to negatively modulate nociception in the superficial dorsal horn of the spinal cord. In the present study, we sought to determine the role of presumably excitatory dorsal horn galanin receptor-expressing neurons in nociception by selectively destroying GalR1-expressing superficial dorsal horn interneurons using lumbar intrathecal injections of the targeted cytotoxin, galanin-saporin (Gal-sap). Lumbar intrathecal injection of Gal-sap (500 ng) reduced immunoperoxidase staining for GalR1 in the superficial dorsal horn without affecting primary afferent neurons in lumbar dorsal root ganglia. Lumbar intrathecal Gal-sap also: 1--reduced nocifensive reflex responding on the thermal plate at 0.3 °C, 44 °C, and 47 °C; 2--increased hot side occupancy in a thermal preference task (15 °C vs 45 °C); and, 3--decreased escape from 44 °C and 47 °C, but not 20 °C. Thus, similar to lesions of mu opiate receptor-expressing dorsal horn interneurons, selective destruction of GalR1-expressing superficial dorsal horn neurons produces heat hypo-algesia, likely due to loss of GalR1-expressing excitatory interneurons leading to reduced activation of nociceptive projection neurons in response to aversive heat. These results are different than those seen with intrathecal neuropeptide Y-saporin and suggest the potential value of selectively targeting GalR1-expressing dorsal horn neurons to control pain.
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Affiliation(s)
- Laurie L Lemons
- Lab of Experimental Neurology, Neurology Service, Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212-2637, USA.
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Yue HY, Fujita T, Kumamoto E. Biphasic modulation by galanin of excitatory synaptic transmission in substantia gelatinosa neurons of adult rat spinal cord slices. J Neurophysiol 2011; 105:2337-49. [DOI: 10.1152/jn.00991.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Although intrathecally administrated galanin modulates nociceptive transmission in a biphasic manner, this has not been fully examined previously. In the present study, the action of galanin on synaptic transmission in the substantia gelatinosa (SG) neurons of adult rat spinal cord slices was examined, using the whole cell patch-clamp technique. Galanin concentration-dependently increased the frequency of spontaneous excitatory postsynaptic current (EPSC; EC50 = 2.0 nM) without changing the amplitude, indicating a presynaptic effect. This effect was reduced in a Ca2+-free, or voltage-gated Ca2+ channel blocker La3+-containing Krebs solution and was produced by a galanin type-2/3 receptor (GalR2/R3) agonist, galanin 2–11, but not by a galanin type-1 receptor (GalR1) agonist, M617. Galanin also concentration-dependently produced an outward current at −70 mV (EC50 = 44 nM), although this appeared to be contaminated by a small inward current. This outward current was mimicked by M617, but not by galanin 2–11. Moreover, galanin reduced monosynaptic Aδ-fiber- and C-fiber-evoked EPSC amplitude; the former reduction was larger than the latter. A similar action was produced by galanin 2–11, but not by M617. Spontaneous and focally evoked inhibitory (GABAergic and glycinergic) transmission was unaffected by galanin. These findings indicate that galanin at lower concentrations enhances the spontaneous release of l-glutamate from nerve terminals by Ca2+ entry from the external solution following GalR2/R3 activation, whereas galanin at higher concentrations also produces a membrane hyperpolarization by activating GalR1. Moreover, galanin reduces l-glutamate release onto SG neurons from primary afferent fibers by activating GalR2/R3. These effects could partially contribute to the behavioral effect of galanin.
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Affiliation(s)
- Hai-Yuan Yue
- Department of Physiology, Saga Medical School, Saga, Japan
| | - Tsugumi Fujita
- Department of Physiology, Saga Medical School, Saga, Japan
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Mitsukawa K, Lu X, Bartfai T. Galanin, galanin receptors, and drug targets. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:7-23. [PMID: 21299058 DOI: 10.1007/978-3-0346-0228-0_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Galanin, a neuropeptide widely expressed in the central and peripheral nervous systems and in the endocrine system, has been shown to regulate numerous physiological and pathological processes through interactions with three G-protein-coupled receptors, GalR1 through GalR3. Over the past decade, some of the receptor subtype-specific effects have been elucidated through pharmacological studies using subtype selective ligands, as well as through molecular approaches involving knockout animals. In this chapter, we summarize the current data which constitute the basis of targeting GalR1, GalR2, and GalR3 for the treatment of various human diseases and pathological conditions, including seizure, Alzheimer's disease, mood disorders, anxiety, alcohol intake in addiction, metabolic diseases, pain and solid tumors.
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Affiliation(s)
- K Mitsukawa
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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21
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Dendritic synthesis and release of the neuropeptide galanin: Morphological evidence from studies on rat locus coeruleus neurons. J Comp Neurol 2009; 516:199-212. [DOI: 10.1002/cne.22105] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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22
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Alier KA, Chen Y, Sollenberg UE, Langel Ü, Smith PA. Selective stimulation of GalR1 and GalR2 in rat substantia gelatinosa reveals a cellular basis for the anti- and pro-nociceptive actions of galanin. Pain 2007; 137:138-146. [PMID: 17910903 DOI: 10.1016/j.pain.2007.08.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 08/08/2007] [Accepted: 08/21/2007] [Indexed: 11/17/2022]
Abstract
Galanin modulates spinal nociceptive processing by interacting with two receptors, GalR1 and GalR2. The underlying neurophysiological mechanisms were examined by whole-cell recording from identified neurons in the substantia gelatinosa of young adult rats. GalR1 was activated with a 'cocktail' containing the GalR1/2 agonist, AR-M 961 (0.5 microM), in the presence of the GalR2 antagonist, M871 (1.0-2.5 microM). GalR2 was activated with the selective agonist, AR-M 1896 (0.5-1.0 microM). Application of the 'GalR1 agonist cocktail' often activated an inwardly-rectifying conductance in delay firing (excitatory) and tonically firing (inhibitory) neurons. This conductance was not activated by AR-M 1896 which instead decreased or increased an outwardly-rectifying conductance at voltages positive to -70 mV. Despite this variability in its actions on current-voltage relationships, AR-M 1896 very consistently decreased membrane excitability, as measured by cumulative action potential latency in response to a depolarizing current ramp. This strong GalR2-mediated effect was seen in neurons where membrane conductance was decreased, and where membrane excitability might be predicted to increase. GalR2 was also located presynaptically, as AR-M 1896 increased the interevent interval of spontaneous EPSCs in both delay and tonic cells. By contrast, the 'GalR1 agonist cocktail' had little effect on spontaneous EPSCs, suggesting that presynaptic terminals do not express GalR1. These diverse actions of GalR1 and GalR2 activation on both inhibitory and excitatory neurons are discussed in relation to the known spinal antinociceptive and pro-nociceptive actions of galanin, to the possible association of GalR1 with the inhibitory G-protein, G(i/o) and to report that GalR2 activation suppresses Ca2+ channel currents.
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Affiliation(s)
- Kwai A Alier
- Department of Pharmacology, University of Alberta, 9.75 Medical Sciences Building, Edmonton, Alta., Canada T6G 2H7 Centre for Neuroscience, University of Alberta, Edmonton, Alta., Canada Department of Neurochemistry, Stockholm University, Stockholm 10691, Sweden
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Brumovsky P, Shi TS, Landry M, Villar MJ, Hökfelt T. Neuropeptide tyrosine and pain. Trends Pharmacol Sci 2007; 28:93-102. [PMID: 17222466 DOI: 10.1016/j.tips.2006.12.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/24/2006] [Accepted: 12/20/2006] [Indexed: 12/20/2022]
Abstract
Research during the past two decades supports a complex role for neuropeptide tyrosine (NPY) and two of its associated receptors, the Y1 receptor and the Y2 receptor, in the modulation of pain, in addition to regeneration and survival mechanisms at the spinal level. Thus, NPY has been shown to both cause and reduce pain, in addition to having biphasic effects. Recent research has focused on the distribution of the spinal NPY-mediated system. Here, we propose various possible scenarios for the role of NPY in pain processing, based on its actions at different sites (axon versus cell body), through different receptors (Y1 receptor versus Y2 receptor) and/or types of neuron (ganglion neurons and intraganglionic cross-excitation versus interneurons versus projection neurons).
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Affiliation(s)
- Pablo Brumovsky
- Department of Neuroscience, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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Brumovsky P, Hygge-Blakeman K, Villar MJ, Watanabe M, Wiesenfeld-Hallin Z, Hökfelt T. Phenotyping of sensory and sympathetic ganglion neurons of a galanin-overexpressing mouse--possible implications for pain processing. J Chem Neuroanat 2006; 31:243-62. [PMID: 16546349 DOI: 10.1016/j.jchemneu.2006.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 02/03/2006] [Accepted: 02/04/2006] [Indexed: 01/16/2023]
Abstract
The distribution of galanin was studied in the lumbar 5 dorsal root ganglia (DRGs) and spinal cord, superior cervical ganglia (SCGs), and skin of transgenic mice overexpressing galanin under the dopamine beta-hydroxylase (DBH) promoter (GalOE-DBH mice) and in wild type (WT) mice. The DRGs and spinal cord were analysed before and after a unilateral, complete transection (axotomy) of the sciatic nerve and after dorsal rhizotomy. Both galanin protein and transcript were studied by, respectively, immunohistochemistry and in situ hybridization. Increased galanin expression was observed in several small, medium-sized and large DRG neuron profiles (NPs) in the naïve transgenic mouse, frequently in neurons lacking calcitonin gene-related peptide (CGRP) and isolectin B4-binding. This lack of coexistence was particularly evident in the medium-sized/large NPs. In the dorsal horn of the spinal cord, no differences were detected between GalOE-DBH and WT mice, both displaying a strong galanin-positive neuropil in the superficial laminae of the dorsal horn, but the transgenic mice showed a more abundant galanin-positive innervation of the ventral horn. A 12-day dorsal rhizotomy, surprisingly, failed to alter the galanin staining patterns in the dorsal (and ventral) dorsal horn. Unilateral axotomy induced upregulation of galanin in DRG NPs of all sizes in both types of mouse. In the hindpaw skin, a profuse galanin-positive fiber plexus was observed in sweat glands and around blood vessels of the transgenic mice, being much more restricted in WT mice. Finally, GalOE mice exhibited a strong galanin-like immunoreactivity in most SCG NPs. The overexpression of the peptide in DRGs and SCGs was paralleled by increased mRNA levels. The present results show that overexpression of galanin under the control of the DBH promoter does not only occur, as expected in these mice, in noradrenline/adrenaline neurons but also in DRG neurons, particularly in large and medium-sized NPs. To what extent and how this overexpression pattern is related to the previously shown elevated pain threshold under normal and lesion conditions is discussed [Grass, S., Crawley, J.N., Xu, X.J., Wiesenfeld-Hallin, Z., 2003a. Reduced spinal cord sensitization to C-fibre stimulation in mice over-expressing galanin. Eur. J. Neurosci. 17, 1829-1832; Hygge-Blakeman, K., Brumovsky, P., Hao, J.X., Xu, X.J., Hökfelt, T., Crawley, J.N., Wiesenfeld-Hallin, Z., 2004. Galanin over-expression decreases the development of neuropathic pain-like behaviour in mice after partial sciatic nerve injury. Brain Res. 1025, 152-158].
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MESH Headings
- Animals
- Axotomy
- Disease Models, Animal
- Dopamine beta-Hydroxylase/genetics
- Galanin/genetics
- Galanin/metabolism
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Ganglia, Sympathetic/cytology
- Ganglia, Sympathetic/metabolism
- Gene Expression Regulation/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Norepinephrine/metabolism
- Pain/genetics
- Pain/metabolism
- Pain/physiopathology
- Phenotype
- Posterior Horn Cells/cytology
- Posterior Horn Cells/metabolism
- Promoter Regions, Genetic/genetics
- RNA, Messenger/metabolism
- Rhizotomy
- Sciatic Neuropathy/genetics
- Sciatic Neuropathy/metabolism
- Sciatic Neuropathy/physiopathology
- Sensory Receptor Cells/metabolism
- Skin/innervation
- Up-Regulation/physiology
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Affiliation(s)
- Pablo Brumovsky
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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