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Gimeno-Ferrer F, Eitner A, Schaible HG, Richter F. Galanin diminishes cortical spreading depolarization across rodents - A candidate for treatment? Neurosci Lett 2024; 832:137814. [PMID: 38723760 DOI: 10.1016/j.neulet.2024.137814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
Galanin (Gal) is a neuropeptide with the potential to ameliorate cortical spreading depolarization (CSD), an electrophysiological phenomenon occurring after brain injury or in migraine aura. Gal is expressed in all cortical neurons both in rat and in mouse cortices. Here we investigated whether the effect of Gal on CSD previously described in the rat is conserved in the mouse cortex. In rats, the topical application of Gal to the cortex for 1 h did not induce any change in CSD amplitudes, propagation velocity, or threshold of elicitation. Rather, topical application of Gal for 3 h was necessary to obtain a significant decrease in these CSD parameters and to develop a remarkable increase in the KCl threshold to elicit a CSD in rat cortex. In contrast, the topical application of Gal on cortical surface for 1 h in mice was sufficient to significantly attenuate CSD amplitudes and increase threshold. A thinner cortex, a faster diffusion or different affinity/expression of receptors for Gal are possible reasons to explain this difference in the time course between rats and mice. Our data are relevant to postulate Gal as a potential target for inhibition of CSD under pathological situations such as stroke or ischemia. SIGNIFICANCE STATEMENT: The neuropeptide Galanin (Gal) is expressed in all neurons throughout the cerebral cortex, both in rats and mice, and is able to reduce or even inhibit Cortical Spreading Depolarization, thus, Gal has the potential to control neuronal excitability that may identify Gal as a target in drug development against CSD.
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Affiliation(s)
- Fátima Gimeno-Ferrer
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, D-07740 Jena, Germany; Present address: University of Augsburg, Faculty of Medicine, Institute for Theoretical Medicine, Vascular Biology Lab, D-86159 Augsburg, Germany
| | - Annett Eitner
- Department of Trauma, Hand and Reconstructive Surgery, Experimental Trauma Surgery, Jena University Hospital, D-07740 Jena, Germany
| | - Hans-Georg Schaible
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, D-07740 Jena, Germany
| | - Frank Richter
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, D-07740 Jena, Germany.
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Gimeno-Ferrer F, Eitner A, Bauer R, Lehmenkühler A, Schaible HG, Richter F. Cortical spreading depolarization is a potential target for rat brain excitability modulation by Galanin. Exp Neurol 2023; 370:114569. [PMID: 37827229 DOI: 10.1016/j.expneurol.2023.114569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 08/24/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
The inhibitory neuropeptide Galanin (Gal) has been shown to mediate anticonvulsion and neuroprotection. Here we investigated whether Gal affects cortical spreading depolarization (CSD). CSD is considered the pathophysiological neuronal mechanism of migraine aura, and a neuronal mechanism aggravating brain damage upon afflictions of the brain. Immunohistochemistry localized Gal and the Gal receptors 1-3 (GalR1-3) in native rat cortex and evaluated microglial morphology after exposure to Gal. In anesthetized rats, Gal was applied alone and together with the GalR antagonists M40, M871, or SNAP 37889 locally to the exposed cortex. The spontaneous electrocorticogram and CSDs evoked by remote KCl pressure microinjection were measured. In rat cortex, Gal was present in all neurons of all cortical layers, but not in astrocytes, microglia and vessels. GalR2 and GalR3 were expressed throughout all neurons, whereas GalR1 was preponderantly located at neurons in layers IV and V, but only in about half of the neurons. In susceptible rats, topical application of Gal on cortex decreased CSD amplitude, slowed CSD propagation velocity, and increased the threshold for KCl to ignite CSD. In some rats, washout of previously applied Gal induced periods of epileptiform patterns in the electrocorticogram. Blockade of GalR2 by M871 robustly prevented all Gal effects on CSD, whereas blockade of GalR1 or GalR3 was less effective. Although microglia did not express GalRs, topical application of Gal changed microglial morphology indicating microglial activation. This effect of Gal on microglia was prevented by blocking neuronal GalR2. In conclusion, Gal has the potential to ameliorate CSD thus reducing pathophysiological neuronal events caused by or associated with CSD.
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Affiliation(s)
- Fátima Gimeno-Ferrer
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany
| | - Annett Eitner
- Department of Trauma, Hand and Reconstructive Surgery, Experimental Trauma Surgery, Jena University Hospital, Jena D-07740, Germany
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, CMB-Center for Molecular Biomedicine, Jena University Hospital, Jena D-07740, Germany
| | | | - Hans-Georg Schaible
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany
| | - Frank Richter
- Institute of Physiology 1/Neurophysiology, Jena University Hospital, Jena D-07740, Germany.
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated NF2 S10 dephosphorylation distinctly regulates kainate-induced seizure susceptibility and neuronal death through PAK1-NF-κB-COX-2-PTGES2 signaling pathway. J Neuroinflammation 2023; 20:99. [PMID: 37118736 PMCID: PMC10141957 DOI: 10.1186/s12974-023-02788-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/23/2023] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) selectively dephosphorylates serine (S) 10 site on neurofibromin 2 (NF2, also known as merlin (moesin-ezrin-radixin-like protein) or schwannomin). p21-activated kinase 1 (PAK1) is a serine/threonine protein kinase, which is involved in synaptic activity and plasticity in neurons. NF2 and PAK1 reciprocally regulate each other in a positive feedback manner. Thus, the aim of the present study is to investigate the effects of PLPP/CIN-mediated NF2 S10 dephosphorylation on PAK1-related signaling pathways under physiological and neuroinflammatory conditions, which are largely unknown. METHODS After kainate (KA) injection in wild-type, PLPP/CIN-/- and PLPP/CINTg mice, seizure susceptibility, PAK1 S204 autophosphorylation, nuclear factor-κB (NF-κB) p65 S276 phosphorylation, cyclooxygenase-2 (COX-2) upregulation, prostaglandin E synthase 2 (PTGES2) induction and neuronal damage were measured. The effects of 1,1'-dithiodi-2-naphthtol (IPA-3, a selective inhibitor of PAK1) pretreatment on these responses to KA were also validated. RESULTS PLPP/CIN overexpression increased PAK1 S204 autophosphorylation concomitant with the enhanced NF2 S10 dephosphorylation in hippocampal neurons under physiological condition. Following KA treatment, PLPP/CIN overexpression delayed the seizure on-set and accelerated PAK1 S204 phosphorylation, NF-κB p65 S276 phosphorylation, COX-2 upregulation and PTGES2 induction, which were ameliorated by PLPP/CIN deletion or IPA-3. Furthermore, IPA-3 pretreatment shortened the latency of seizure on-set without affecting seizure severity (intensity) and ameliorated CA3 neuronal death induced by KA. CONCLUSIONS These findings indicate that PLPP/CIN may regulate seizure susceptibility (the latency of seizure on-set) and CA3 neuronal death in response to KA through NF2-PAK1-NF-κB-COX-2-PTGES2 signaling pathway.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea.
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Metcalf CS, Gagangras S, Bulaj G, White HS. Synergistic effects of the galanin analog 810-2 with the antiseizure medication levetiracetam in rodent seizure models. Epilepsia 2022; 63:3090-3099. [PMID: 36177529 DOI: 10.1111/epi.17420] [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: 07/27/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE The use of many antiseizure medications (ASMs) is limited due to pharmacoresistance and dose-limiting side effects, suggesting an unmet need for novel therapeutic approaches. The neuropeptide galanin reduces seizures in several preclinical seizure and epilepsy models, but its clinical utility is limited due to rapid metabolism and poor blood-brain barrier penetration. The lead galanin analog 810-2 is systemically bioavailable and reduces seizures when administered alone. Further development of this analog, with the potential for use as an add-on therapy in patients with epilepsy, requires a better understanding of the use of this analog in combination with approved ASMs. We sought to evaluate 810-2 in combination with commonly used ASMs in rodent models of seizures. METHODS The mouse 6-Hz seizure assay was used to test efficacy of 810-2 in combination with levetiracetam (LEV), valproic acid (VPA), or lacosamide (LCM) using a 1:1 dose ratio in isobolographic studies. Further characterization was performed for the combination of 810-2 and LEV in the mouse corneal kindling and rat 6-Hz assays. RESULTS Whereas the combination of 810-2 with VPA and LCM yielded additive interactions, the combination of 810-2 with LEV demonstrated a synergistic interaction in the mouse 6-Hz assay. Supra-additive effects were also observed in the mouse corneal kindling and rat 6-Hz assays for this combination. SIGNIFICANCE The combination of 810-2 with LEV suggests the potential for this galanin analog to be further developed as an add-on therapy for patients with epilepsy, particularly when coadministered with LEV.
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Affiliation(s)
- Cameron S Metcalf
- Epilepsy Therapy Screening Program Contract Site, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
| | - Saurabh Gagangras
- Epilepsy Therapy Screening Program Contract Site, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
| | - Grzegorz Bulaj
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
| | - H Steve White
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA, USA
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated DARPP-32 serine 97 dephosphorylation delays the seizure onset in response to kainic acid in the mouse hippocampus. Neuropharmacology 2022; 219:109238. [PMID: 36055413 DOI: 10.1016/j.neuropharm.2022.109238] [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: 04/21/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022]
Abstract
Dopamine and cAMP-regulated phosphoprotein, 32 kDa (DARPP-32)-mediated protein phosphatase 1 (PP1) inhibition leads to the increase in phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR), which potentiates channel activity and current and thereby may facilitate seizure activity. In the present study, we found that pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) transiently dephosphorylated DARPP-32 serine (S) 97 site in the early time window, and casein kinase 2 (CK2) subsequently phosphorylated this site in the later time points after kainic acid (KA) injection, which increased the latency of seizure onset in response to KA, but exacerbated the intensity (severity), duration and progression of seizures. TMCB (a CK2 inhibitor) delayed the seizure onset in response to KA, concomitant with the reduced DARPP-32 S97 phosphorylation. Therefore, our findings suggest that PLPP/CIN may play an important role in the latency of seizure onset via DARPP-32-PP1-AMPAR signaling pathway, and may be one of the potential therapeutic targets for medication of seizure or epilepsy.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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Janković SM, Đešević M. Advancements in neuroactive peptides in seizures. Expert Rev Neurother 2022; 22:129-143. [DOI: 10.1080/14737175.2022.2031983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Slobodan M. Janković
- - University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
- University Clinical Center, Kragujevac, Serbia
| | - Miralem Đešević
- - Private Policlinic Center Eurofarm Sarajevo, Cardiology Department, Sarajevo, Bosnia and Herzegovina
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Gan CL, Zou Y, Xia Y, Zhang T, Chen D, Lan G, Mei Y, Wang L, Shui X, Hu L, Liu H, Lee TH. Inhibition of Death-associated Protein Kinase 1 protects against Epileptic Seizures in mice. Int J Biol Sci 2021; 17:2356-2366. [PMID: 34239362 PMCID: PMC8241737 DOI: 10.7150/ijbs.59922] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/28/2021] [Indexed: 11/05/2022] Open
Abstract
Epilepsy is a chronic encephalopathy and one of the most common neurological disorders. Death-associated protein kinase 1 (DAPK1) expression has been shown to be upregulated in the brains of human epilepsy patients compared with those of normal subjects. However, little is known about the impact of DAPK1 on epileptic seizure conditions. In this study, we aim to clarify whether and how DAPK1 is regulated in epilepsy and whether targeting DAPK1 expression or activity has a protective effect against epilepsy using seizure animal models. Here, we found that cortical and hippocampal DAPK1 activity but not DAPK1 expression was increased immediately after convulsive pentylenetetrazol (PTZ) exposure in mice. However, DAPK1 overexpression was found after chronic low-dose PTZ insults during the kindling paradigm. The suppression of DAPK1 expression by genetic knockout significantly reduced PTZ-induced seizure phenotypes and the development of kindled seizures. Moreover, pharmacological inhibition of DAPK1 activity exerted rapid antiepileptic effects in both acute and chronic epilepsy mouse models. Mechanistically, PTZ stimulated the phosphorylation of NR2B through DAPK1 activation. Combined together, these results suggest that DAPK1 regulation is a novel mechanism for the control of both acute and chronic epilepsy and provide new therapeutic strategies for the treatment of human epilepsy.
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Affiliation(s)
- Chen-Ling Gan
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China.,Fujian Provincial Key Laboratory of Natural Medicine Pharmacology, Institute of Materia Medical, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Yulian Zou
- Immunotherapy Institute, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Yongfang Xia
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Tao Zhang
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Dongmei Chen
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Guihua Lan
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Yingxue Mei
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Long Wang
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Xindong Shui
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Li Hu
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Hekun Liu
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Tae Ho Lee
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated Mdm2 dephosphorylation increases seizure susceptibility via abrogating PSD95 ubiquitination. Exp Neurol 2020; 331:113383. [DOI: 10.1016/j.expneurol.2020.113383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 01/29/2023]
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Yu Y, Nguyen DT, Jiang J. G protein-coupled receptors in acquired epilepsy: Druggability and translatability. Prog Neurobiol 2019; 183:101682. [PMID: 31454545 DOI: 10.1016/j.pneurobio.2019.101682] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/09/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023]
Abstract
As the largest family of membrane proteins in the human genome, G protein-coupled receptors (GPCRs) constitute the targets of more than one-third of all modern medicinal drugs. In the central nervous system (CNS), widely distributed GPCRs in neuronal and nonneuronal cells mediate numerous essential physiological functions via regulating neurotransmission at the synapses. Whereas their abnormalities in expression and activity are involved in various neuropathological processes. CNS conditions thus remain highly represented among the indications of GPCR-targeted agents. Mounting evidence from a large number of animal studies suggests that GPCRs play important roles in the regulation of neuronal excitability associated with epilepsy, a common CNS disease afflicting approximately 1-2% of the population. Surprisingly, none of the US Food and Drug Administration (FDA)-approved (>30) antiepileptic drugs (AEDs) suppresses seizures through acting on GPCRs. This disparity raises concerns about the translatability of these preclinical findings and the druggability of GPCRs for seizure disorders. The currently available AEDs intervene seizures predominantly through targeting ion channels and have considerable limitations, as they often cause unbearable adverse effects, fail to control seizures in over 30% of patients, and merely provide symptomatic relief. Thus, identifying novel molecular targets for epilepsy is highly desired. Herein, we focus on recent progresses in understanding the comprehensive roles of several GPCR families in seizure generation and development of acquired epilepsy. We also dissect current hurdles hindering translational efforts in developing GPCRs as antiepileptic and/or antiepileptogenic targets and discuss the counteracting strategies that might lead to a potential cure for this debilitating CNS condition.
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Affiliation(s)
- Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Davis T Nguyen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Drexel M, Locker F, Kofler B, Sperk G. Effects of galanin receptor 2 and receptor 3 knockout in mouse models of acute seizures. Epilepsia 2018; 59:e166-e171. [PMID: 30298565 PMCID: PMC6282553 DOI: 10.1111/epi.14573] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 12/04/2022]
Abstract
There exists solid evidence that endogenous galanin and galanin agonists exert anticonvulsive actions mediated both by galanin 1 receptor (GAL1‐R) and galanin 2 receptor (GAL2‐R). We have now investigated whether depletion of the recently identified third galanin receptor, GAL3‐R, and that of GAL2‐R, alters the threshold to the systemically applied γ‐aminobutyric acid (GABA) antagonist pentylenetetrazole (PTZ) or to intrahippocampally administered kainic acid (KA). In neither model, GAL3‐KO mice differed in their latency to the first seizure, mean seizure duration, total number of seizures, or time spent in seizures compared to wild‐type controls. In addition, consistent with previous data, the response to PTZ was not altered in GAL2‐KO mice. In contrast, intrahippocampal KA resulted in a significantly increased number of seizures and time spent in seizures in GAL2‐KO mice, although the latency to the first seizure and the duration of individual seizures was not altered. These results are consistent with the previous data showing that GAL2‐R knockdown does not affect the number of perforant path stimulations required for initiating status epilepticus but significantly increases the seizure severity during the ongoing status. In conclusion, our data support a specific role of GAL2‐R but not of GAL3‐R in mediating the anticonvulsive actions of endogenous galanin.
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Affiliation(s)
- Meinrad Drexel
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Felix Locker
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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