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Sheng W, Yu M, Wang X, Jin M, Pang X, Li C, Zhang S, Li P, Wang X, Zhang C, Zhang Y, Liu K. Localization of neuropeptide receptor NPY4R in rat retina. Neuropeptides 2022; 93:102246. [PMID: 35453028 DOI: 10.1016/j.npep.2022.102246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/24/2022] [Accepted: 04/03/2022] [Indexed: 11/21/2022]
Abstract
Neuropeptide Y (NPY) is a significant neuromodulator implicated in a multitude of physiological functions via activating NPY receptors which belong to seven transmembrane G-protein-coupled receptors (GPCRs). However, the detailed cellular expression of NPY receptors in retina has been scarcely investigated. In this study, the expression of the special NPY4R receptor in rat retina was assessed using Western blot analysis and immunofluorescent staining. The detailed cellular localization of NPY4R receptor was studied using double immunofluorescent staining and laser-scanning confocal microscopy. Our data demonstrated that NPY4R receptor was weakly expressed in the inner segment of outer photoreceptors and extensively expressed in the outer segment of S-opsin-positive blue cones, L/M-opsin-positive red/green cones and in the somata of CB-positive horizontal cells, GAD65-positive GABAnergic amacrine cells, ChAT-positive cholinergic amacrine cells, TH-positive dopaminergic CA1 amacrine cells and CA2 amacrine cells, PV-positive AII amacrine cells, Brn3a-positive conventional ganglion cells and melanopsin-containing ipRGCs. In addition, NPY4R receptor was diffusely distributed throughout the full thickness of the inner plexiform layer and outer plexiform layer. However, the outer segment of Rho4D2-positive rods, the somata of ChX10-positive bipolar cells and CRALBP-positive Müller glial cells seemed to lack immunoreactivity of NPY4R receptor. The new finding that multiple types of retinal cell express NPY4R receptor provides new neurobiological basis for the participation of NPY in the regulation of retinal functions through activating NPY4R receptor.
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Affiliation(s)
- Wenlong Sheng
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China.
| | - Miaohui Yu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Xue Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Meng Jin
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Xiangming Pang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Can Li
- School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Shanshan Zhang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Peihai Li
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Xixin Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Changqing Zhang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Yun Zhang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China
| | - Kechun Liu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China; Engineering Research Center of Zebrafish Models for Human Diseases and Drug Screening of Shandong Province, Jinan, China; Shandong Provincial Engineering Laboratory for Biological Testing Technology, Jinan, China.
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Prognostic and Functional Analysis of NPY6R in Uveal Melanoma Using Bioinformatics. DISEASE MARKERS 2022; 2022:4143447. [PMID: 35432628 PMCID: PMC9012612 DOI: 10.1155/2022/4143447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 12/14/2022]
Abstract
Neuropeptides can mediate tumor cell proliferation and differentiation through autocrine, paracrine, neurosecretory, and endocrine mechanisms. This study investigated the expression and prognostic significance of neuropeptide Y receptor Y6 (NPY6R) in uveal melanoma (UVM) and preliminarily investigated the biological function of NPY6R in UVM. NPY6R was poorly expressed in most tumors and was associated with better prognosis in UVM. Among the clinicopathological features of UVM, NPY6R expression was lower in male patients. The area under the curve (AUC) value of NPY6R for the diagnosis of UVM was 0.676 (95% CI: 0.556–0.795). A nomogram including four clinical predictors was constructed. NPY6R expression was significantly associated with features of the UVM immune microenvironment. ESTIMATE and CIBERSORT algorithms were used to calculate the fraction of immune cells and the percentage of infiltration in each patient, respectively. NPY6R expression-related gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analyses were performed. GO and KEGG enrichment analyses revealed that NPY6R-related genes are mainly enriched in pathways and functions related to visual light perception. Gene set enrichment analysis suggested that NPY6R is associated with tumor progression in UVM. NPY6R is involved in the tumor progression of UVM and has a good predictive value as a prognostic marker of UVM.
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Campos EJ, Martins J, Brudzewsky D, Correia S, Santiago AR, Woldbye DP, Ambrósio AF. Impact of type 1 diabetes mellitus and sitagliptin treatment on the neuropeptide Y system of rat retina. Clin Exp Ophthalmol 2018; 46:783-795. [PMID: 29442423 DOI: 10.1111/ceo.13176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 02/06/2018] [Accepted: 02/10/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Neuropeptide Y (NPY) is a neuromodulator that is expressed in the retina. Increasing evidence suggests that NPY has pronounced anti-inflammatory effects, which might depend on the inhibition of dipeptidyl-peptidase-IV (DPP-IV). The aim of this study was to investigate the impact of type 1 diabetes mellitus (DM) and sitagliptin, a DPP-IV inhibitor, on the NPY system in the retina using an animal model. METHODS Type 1 DM was induced in male Wistar rats by an intraperitoneal injection of streptozotocin. Starting 2 weeks after DM onset, animals were treated orally with sitagliptin (5 mg/kg.day) for 2 weeks. The expression of NPY and NPY receptors (Y1 , Y2 and Y5 receptors) was measured by quantitative polymerase chain reaction, Western blot and/or enzyme-linked immunosorbent assay. The immunoreactivity of NPY and NPY receptors was evaluated by immunohistochemistry, and the [35 S]GTPγS binding assay was used to assess the functional binding of NPY receptors. RESULTS DM decreased the mRNA levels of NPY in the retina, as well as the protein levels of NPY and Y5 receptor. No changes were detected in the localization of NPY and NPY receptors in the retina and in the functional binding of NPY to all receptors. Sitagliptin alone reduced retinal NPY mRNA levels. The effects of DM on the NPY system were not affected by sitagliptin. CONCLUSION DM modestly affects the NPY system in the retina and these effects are not prevented by sitagliptin treatment. These observations suggest that DPP-IV enzyme is not underlying the NPY changes detected in the retina induced by type 1 DM.
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Affiliation(s)
- Elisa J Campos
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - João Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Dan Brudzewsky
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Sandra Correia
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - David Pd Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
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Christiansen AT, Kiilgaard JF, Klemp K, Woldbye DPD, Hannibal J. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study. J Comp Neurol 2018; 526:1877-1895. [DOI: 10.1002/cne.24455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/24/2022]
Affiliation(s)
| | - Jens Folke Kiilgaard
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - Kristian Klemp
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - David Paul Drucker Woldbye
- Laboratory of Neural Plasticity; Center for Neuroscience, Faculty of Health Sciences, University of Copenhagen; Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry; Copenhagen University Hospital, Bispebjerg Hospital; Copenhagen Denmark
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Martins J, Elvas F, Brudzewsky D, Martins T, Kolomiets B, Tralhão P, Gøtzsche CR, Cavadas C, Castelo-Branco M, Woldbye DPD, Picaud S, Santiago AR, Ambrósio AF. Activation of Neuropeptide Y Receptors Modulates Retinal Ganglion Cell Physiology and Exerts Neuroprotective Actions In Vitro. ASN Neuro 2015; 7:7/4/1759091415598292. [PMID: 26311075 PMCID: PMC4552225 DOI: 10.1177/1759091415598292] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuropeptide Y (NPY) is expressed in mammalian retina but the location and potential modulatory effects of NPY receptor activation remain largely unknown. Retinal ganglion cell (RGC) death is a hallmark of several retinal degenerative diseases, particularly glaucoma. Using purified RGCs and ex vivo rat retinal preparations, we have measured RGC intracellular free calcium concentration ([Ca2+]i) and RGC spiking activity, respectively. We found that NPY attenuated the increase in the [Ca2+]i triggered by glutamate mainly via Y1 receptor activation. Moreover, (Leu31, Pro34)−NPY, a Y1/Y5 receptor agonist, increased the initial burst response of OFF-type RGCs, although no effect was observed on RGC spontaneous spiking activity. The Y1 receptor activation was also able to directly modulate RGC responses by attenuating the NMDA-induced increase in RGC spiking activity. These results suggest that Y1 receptor activation, at the level of inner or outer plexiform layers, leads to modulation of RGC receptive field properties. Using in vitro cultures of rat retinal explants exposed to NMDA, we found that NPY pretreatment prevented NMDA-induced cell death. However, in an animal model of retinal ischemia-reperfusion injury, pretreatment with NPY or (Leu31, Pro34)−NPY was not able to prevent apoptosis or rescue RGCs. In conclusion, we found modulatory effects of NPY application that for the first time were detected at the level of RGCs. However, further studies are needed to evaluate whether NPY neuroprotective actions detected in retinal explants can be translated into animal models of retinal degenerative diseases.
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Affiliation(s)
- João Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Dan Brudzewsky
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Tânia Martins
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal
| | - Bogdan Kolomiets
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Pedro Tralhão
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - Casper R Gøtzsche
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Cláudia Cavadas
- CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Miguel Castelo-Branco
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal
| | - David P D Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Serge Picaud
- Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, UMR_S968, 75012 Paris, France
| | - Ana R Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - António F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548 Coimbra, Portugal CNC.IBILI, University of Coimbra, 3004-548 Coimbra, Portugal AIBILI, 3000-548 Coimbra, Portugal Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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Santos-Carvalho A, Ambrósio AF, Cavadas C. Neuropeptide Y system in the retina: From localization to function. Prog Retin Eye Res 2015; 47:19-37. [DOI: 10.1016/j.preteyeres.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/05/2015] [Accepted: 03/10/2015] [Indexed: 01/10/2023]
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Santos-Carvalho A, Álvaro AR, Martins J, Ambrósio AF, Cavadas C. Emerging novel roles of neuropeptide Y in the retina: from neuromodulation to neuroprotection. Prog Neurobiol 2013; 112:70-9. [PMID: 24184719 DOI: 10.1016/j.pneurobio.2013.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
Neuropeptide Y (NPY) and NPY receptors are widely expressed in the central nervous system, including the retina. Retinal cells, in particular neurons, astrocytes, and Müller, microglial and endothelial cells express this peptide and its receptors (Y1, Y2, Y4 and/or Y5). Several studies have shown that NPY is expressed in the retina of various mammalian and non-mammalian species. However, studies analyzing the distribution of NPY receptors in the retina are still scarce. Although the physiological roles of NPY in the retina have not been completely elucidated, its early expression strongly suggests that NPY may be involved in the development of retinal circuitry. NPY inhibits the increase in [Ca(2+)]i triggered by elevated KCl in retinal neurons, protects retinal neural cells against toxic insults and induces the proliferation of retinal progenitor cells. In this review, we will focus on the roles of NPY in the retina, specifically proliferation, neuromodulation and neuroprotection. Alterations in the NPY system in the retina might contribute to the pathogenesis of retinal degenerative diseases, such as diabetic retinopathy and glaucoma, and NPY and its receptors might be viewed as potentially novel therapeutic targets.
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Affiliation(s)
- Ana Santos-Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Ana Rita Álvaro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Biology and Environment, University of Trás-os-Montes and Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal
| | - João Martins
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - António Francisco Ambrósio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548 Coimbra, Portugal; AIBILI-Association for Innovation and Biomedical Research on Light and Image, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Cláudia Cavadas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
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Alvaro AR, Rosmaninho-Salgado J, Santiago AR, Martins J, Aveleira C, Santos PF, Pereira T, Gouveia D, Carvalho AL, Grouzmann E, Ambrósio AF, Cavadas C. NPY in rat retina is present in neurons, in endothelial cells and also in microglial and Müller cells. Neurochem Int 2007; 50:757-63. [PMID: 17353067 DOI: 10.1016/j.neuint.2007.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 12/12/2006] [Accepted: 01/22/2007] [Indexed: 10/23/2022]
Abstract
NPY is present in the retina of different species but its role is not elucidated yet. In this work, using different rat retina in vitro models (whole retina, retinal cells in culture, microglial cell cultures, rat Müller cell line and retina endothelial cell line), we demonstrated that NPY staining is present in the retina in different cell types: neurons, macroglial, microglial and endothelial cells. Retinal cells in culture express NPY Y(1), Y(2), Y(4) and Y(5) receptors. Retina endothelial cells express all NPY receptors except NPY Y(5) receptor. Moreover, NPY is released from retinal cells in culture upon depolarization. In this study we showed for the first time that NPY is present in rat retina microglial cells and also in rat Müller cells. These in vitro models may open new perspectives to study the physiology and the potential pathophysiological role of NPY in the retina.
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Affiliation(s)
- Ana Rita Alvaro
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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Ke JB, Zhong YM. Expression of somatostatin receptor subtype 5 in rat retinal amacrine cells. Neuroscience 2007; 144:1025-32. [PMID: 17156933 DOI: 10.1016/j.neuroscience.2006.10.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2006] [Revised: 10/27/2006] [Accepted: 10/27/2006] [Indexed: 01/01/2023]
Abstract
Somatostatin (SRIF), as a neuroactive peptide in the CNS, exerts its actions via five subtypes of specific receptors (ssts). In this work, the localization of sst(5) was studied immunocytochemically in rat retinal amacrine cells (ACs). Labeling for sst(5) was diffusely distributed throughout the full thickness of the inner plexiform layer (IPL) and formed two distinct fluorescence bands in the distal part of the IPL. Double labeling experiments showed that sst(5) was expressed in GABAergic ACs. It was further shown that labeling for sst(5) was observed in both dopaminergic and cholinergic ACs, stained by tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT), respectively. The immunostaining appeared mainly on the cell membranes and somatodendritic compartments of these ACs. For the cholinergic ACs, weak sst(5)-immunoreactivity was also observed in the processes terminating in the IPL. In contrast, no sst(5)-immunoreactivity was found in glycinergic AII ACs, stained by parvalbumin (PV). Furthermore, labeling for SRIF was co-localized with sst(5) in both dopaminergic and cholinergic ACs. These results suggest that sst(5) may serve as an autoreceptor or conventional receptor in retinal ACs.
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Affiliation(s)
- J-B Ke
- Institute of Neurobiology and Institutes of Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, PR China
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Uckermann O, Wolf A, Kutzera F, Kalisch F, Beck-Sickinger AG, Wiedemann P, Reichenbach A, Bringmann A. Glutamate release by neurons evokes a purinergic inhibitory mechanism of osmotic glial cell swelling in the rat retina: activation by neuropeptide Y. J Neurosci Res 2006; 83:538-50. [PMID: 16435394 DOI: 10.1002/jnr.20760] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glial cell swelling is a central cause of ischemic edema in the brain and retina; however, the regulation of glial cell volume by endogenous factors in situ is largely unknown. In slices of the postischemic retina of the rat, the somata of glial (Müller) cells swell upon hypotonic stress that is not observed in slices of control retinas. We describe an endogenous signaling pathway that leads to inhibition of the osmotic glial cell swelling, and that is evoked by the release of glutamate from retinal neurons upon application of neuropeptide Y. Glutamate activates metabotropic glutamate receptors on swollen glial cells, which evokes a Ca2+ -independent purinergic signaling cascade that involves release of ATP, P2Y1 receptor activation, and transporter-mediated release of adenosine. Activation of A1 receptors causes the inhibition of osmotic glial cell swelling, by a protein kinase A-dependent activation of K+ and Cl- channels. It is proposed that the glutamate-evoked purinergic receptor signaling of glial cells is crucially involved in the cell volume homeostasis of the retina, and that this mechanism may contribute to the protective effect of adenosine in the ischemic tissue.
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Affiliation(s)
- Ortrud Uckermann
- Paul Flechsig Institute of Brain Research, Medical Faculty of the University of Leipzig, Leipzig, Germany
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D'Angelo I, Brecha NC. Y2 receptor expression and inhibition of voltage-dependent Ca2+ influx into rod bipolar cell terminals. Neuroscience 2004; 125:1039-49. [PMID: 15120863 DOI: 10.1016/j.neuroscience.2003.10.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2003] [Indexed: 11/21/2022]
Abstract
Neuropeptide Y (NPY) is a potent inhibitory neuropeptide expressed by amacrine cells in the rat retina. NPY modulates the release of multiple neurotransmitters in mammalian retina, yet the mechanisms mediating this regulation are not well defined. To further understand the action of NPY in the retina, Y receptor coupling to voltage-dependent Ca(2+) channels was investigated using Ca(2+) imaging with fura-2 AM to measure [Ca(2+)](i) increases in rod bipolar cell terminals. Y receptor expression was studied in rat retinal tissue with reverse transcription-polymerase chain reaction (RT-PCR). NPY inhibited the depolarization-evoked Ca(2+) influx into rod bipolar cell axon terminals and caused a dose-dependent reduction and an average maximal inhibition of 72% at 1 microM, which was reversed upon washout. K(+)-evoked Ca(2+) increases were also inhibited by the selective Y2 receptor agonists, C2-NPY and NPY(13-36), at concentrations of 1 microM, but not by the selective Y1 receptor agonist, [Leu(31)Pro(34)]NPY, selective Y4 receptor agonist, rPP, or the selective Y5 receptor agonist, [d-Trp32]-NPY. Y receptor expression was determined using RT-PCR for all known Y receptor subtypes. Y2 receptor mRNA, as well as Y1, Y4, and Y5 receptor mRNAs, are present in the rat retina. Like the rod bipolar cell, other studies in central neurons have shown that the Y2 receptor is expressed predominantly as a presynaptic receptor and that it modulates transmitter release. Together, these findings suggest that NPY activates presynaptic Y2 receptors to inhibit voltage-dependent Ca(2+) influx into rod bipolar cell terminals, and establishes one mechanism by which NPY may reduce l-glutamate release from the rod bipolar cell synapse.
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Affiliation(s)
- I D'Angelo
- Department of Neurobiology, Box 951763, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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