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Smorodina E, Kav B, Fatafta H, Strodel B. Effects of ion type and concentration on the structure and aggregation of the amyloid peptide A β 16 - 22 $$ {\boldsymbol{\beta}}_{16-22} $$. Proteins 2023. [PMID: 37964477 DOI: 10.1002/prot.26635] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/18/2023] [Accepted: 10/30/2023] [Indexed: 11/16/2023]
Abstract
Among the various factors controlling the amyloid aggregation process, the influences of ions on the aggregation rate and the resulting structures are important aspects to consider, which can be studied by molecular simulations. There is a wide variety of protein force fields and ion models, raising the question of which model to use in such studies. To address this question, we perform molecular dynamics simulations of Aβ16-22 , a fragment of the Alzheimer's amyloid β peptide, using different protein force fields, AMBER99SB-disp (A99-d) and CHARMM36m (C36m), and different ion parameters. The influences of NaCl and CaCl2 at various concentrations are studied and compared with the systems without the addition of ions. Our results indicate a sensitivity of the peptide-ion interactions to the different ion models. In particular, we observe a strong binding of Ca2+ to residue E22 with C36m and also with the Åqvist ion model used together with A99-d, which slightly affects the monomeric Aβ16-22 structures and the aggregation rate, but significantly affects the oligomer structures formed in the aggregation simulations. For example, at high Ca2+ concentrations, there was a switch from an antiparallel to a parallel β-sheet. Such ionic influences are of biological relevance because local ion concentrations can change in vivo and could help explain the polymorphism of amyloid fibrils.
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Affiliation(s)
- Eva Smorodina
- Institute of Biological Information Processing: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Department of Immunology, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Batuhan Kav
- Institute of Biological Information Processing: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Hebah Fatafta
- Institute of Biological Information Processing: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Birgit Strodel
- Institute of Biological Information Processing: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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2
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Tauskela JS, Brunette E, Aylsworth A, Zhao X. Neuroprotection against supra-lethal 'stroke in a dish' insults by an anti-excitotoxic receptor antagonist cocktail. Neurochem Int 2022; 158:105381. [PMID: 35764225 DOI: 10.1016/j.neuint.2022.105381] [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: 04/28/2022] [Revised: 06/07/2022] [Accepted: 06/19/2022] [Indexed: 10/17/2022]
Abstract
The goal of this study was to identify cocktails of drugs able to protect cultured rodent cortical neurons against increasing durations of oxygen-glucose deprivation (OGD). As expected, a cocktail composed of an NMDA and AMPA receptor antagonists and a voltage gated Ca2+ channel blocker (MK-801, CNQX and nifedipine, respectively) provided complete neuroprotection against mild OGD. Increasingly longer durations of OGD necessitated increasing the doses of MK-801 and CNQX, until these cocktails ultimately failed to provide neuroprotection against supra-lethal OGD, even at maximal drug concentrations. Surprisingly, supplementation of any of these cocktails with blockers of TRPM7 channels for increasing OGD durations was not neuroprotective, unless these blockers possessed the ability to inhibit NMDA receptors. Supplementation of the maximally effective cocktail with other NMDA receptor antagonists augmented neuroprotection, suggesting insufficient NMDAR blockade by MK-801. Substitution of MK-801 in cocktails with high concentrations of a glycine site NMDA receptor antagonist caused the greatest improvements in neuroprotection, with the more potent SM-31900 superior to L689,560. Substitution of CQNX in cocktails with AMPA receptor antagonists at high concentrations also improved neuroprotection, particularly with the combination of SYM 2206 and NBQX. The most neuroprotective cocktail was thus composed of SM-31900, SYM2206, NBQX, nifedipine and the antioxidant trolox. Thus, the cumulative properties of antagonist potency and concentration in a cocktail dictate neuroprotective efficacy. The central target of supra-lethal OGD is excitotoxicity, which must be blocked to the greatest extent possible to minimize ion influx.
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Affiliation(s)
- Joseph S Tauskela
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6.
| | - Eric Brunette
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
| | - Amy Aylsworth
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
| | - Xigeng Zhao
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
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Rajani V, Sengar AS, Salter MW. Tripartite signalling by NMDA receptors. Mol Brain 2020; 13:23. [PMID: 32070387 PMCID: PMC7029596 DOI: 10.1186/s13041-020-0563-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/03/2020] [Indexed: 12/31/2022] Open
Abstract
N-methyl-d-aspartate receptors (NMDARs) are excitatory glutamatergic receptors that are fundamental for many neuronal processes, including synaptic plasticity. NMDARs are comprised of four subunits derived from heterogeneous subunit families, yielding a complex diversity in NMDAR form and function. The quadruply-liganded state of binding of two glutamate and two glycine molecules to the receptor drives channel gating, allowing for monovalent cation flux, Ca2+ entry and the initiation of Ca2+-dependent signalling. In addition to this ionotropic function, non-ionotropic signalling can be initiated through the exclusive binding of glycine or of glutamate to the NMDAR. This binding may trigger a transmembrane conformational change of the receptor, inducing intracellular protein-protein signalling between the cytoplasmic domain and secondary messengers. In this review, we outline signalling cascades that can be activated by NMDARs and propose that the receptor transduces signalling through three parallel streams: (i) signalling via both glycine and glutamate binding, (ii) signalling via glycine binding, and (iii) signalling via glutamate binding. This variety in signal transduction mechanisms and downstream signalling cascades complements the widespread prevalence and rich diversity of NMDAR activity throughout the central nervous system and in disease pathology.
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Affiliation(s)
- Vishaal Rajani
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Ameet S Sengar
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Michael W Salter
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada. .,Department of Physiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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Spencer SA, Suárez-Pozos E, Escalante M, Myo YP, Fuss B. Sodium-Calcium Exchangers of the SLC8 Family in Oligodendrocytes: Functional Properties in Health and Disease. Neurochem Res 2020; 45:1287-1297. [PMID: 31927687 DOI: 10.1007/s11064-019-02949-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022]
Abstract
The solute carrier 8 (SLC8) family of sodium-calcium exchangers (NCXs) functions as an essential regulatory system that couples opposite fluxes of sodium and calcium ions across plasmalemmal membranes. NCXs, thereby, play key roles in maintaining an ion homeostasis that preserves cellular integrity. Hence, alterations in NCX expression and regulation have been found to lead to ionic imbalances that are often associated with intracellular calcium overload and cell death. On the other hand, intracellular calcium has been identified as a key driver for a multitude of downstream signaling events that are crucial for proper functioning of biological systems, thus highlighting the need for a tightly controlled balance. In the CNS, NCXs have been primarily characterized in the context of synaptic transmission and ischemic brain damage. However, a much broader picture is emerging. NCXs are expressed by virtually all cells of the CNS including oligodendrocytes (OLGs), the cells that generate the myelin sheath. With a growing appreciation of dynamic calcium signals in OLGs, NCXs are becoming increasingly recognized for their crucial roles in shaping OLG function under both physiological and pathophysiological conditions. In order to provide a current update, this review focuses on the importance of NCXs in cells of the OLG lineage. More specifically, it provides a brief introduction into plasmalemmal NCXs and their modes of activity, and it discusses the roles of OLG expressed NCXs in regulating CNS myelination and in contributing to CNS pathologies associated with detrimental effects on OLG lineage cells.
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Affiliation(s)
- Samantha A Spencer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Edna Suárez-Pozos
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Yu Par Myo
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.
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Caputo MP, Williams JN, Drnevich J, Radlowski EC, Larsen RJ, Sutton BP, Leyshon BJ, Hussain J, Nakamura MT, Kuchan MJ, Das T, Johnson RW. Hydrolyzed Fat Formula Increases Brain White Matter in Small for Gestational Age and Appropriate for Gestational Age Neonatal Piglets. Front Pediatr 2020; 8:32. [PMID: 32117837 PMCID: PMC7029735 DOI: 10.3389/fped.2020.00032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 01/22/2020] [Indexed: 12/23/2022] Open
Abstract
Background: Intrauterine growth restriction is a common cause of small for gestational age (SGA) infants worldwide. SGA infants are deficient in digestive enzymes required for fat digestion and absorption compared to appropriate for gestational age (AGA) infants, putting them at risk for impaired neurocognitive development. Objective: The objective was to determine if a hydrolyzed fat (HF) infant formula containing soy free fatty acids, 2-monoacylglycerolpalmitate, cholesterol, and soy lecithin could increase brain tissue incorporation of essential fatty acids or white matter to enhance brain development in SGA and AGA neonatal piglet models. Methods: Sex-matched, littermate pairs of SGA (0.5-0.9 kg) and AGA (1.2-1.8 kg) 2 days old piglets (N = 60) were randomly assigned to control (CON) or HF formula diets in a 2 × 2 factorial design. On day 14, 24 piglets were used for hippocampal RNA-sequencing; the rest began a spatial learning task. On days 26-29, brain structure was assessed by magnetic resonance imaging (MRI). Cerebellum and hippocampus were analyzed for fatty acid content. Results: SGA piglets grew more slowly than AGA piglets, with no effect of diet on daily weight gain or weight at MRI. HF diet did not affect brain weight. HF diet increased relative volumes of 7 brain regions and white matter (WM) volume in both SGA and AGA piglets. However, HF did not ameliorate SGA total WM integrity deficits. RNA sequencing revealed SGA piglets had increased gene expression of synapse and cell signaling pathways and decreased expression of ribosome pathways in the hippocampus compared to AGA. HF decreased expression of immune response related genes in the hippocampus of AGA and SGA piglets, but did not correct gene expression patterns in SGA piglets. Piglets learned the T-maze task at the same rate, but SGA HF, SGA CON, and AGA HF piglets had more accurate performance than AGA CON piglets on reversal day 2. HF increased arachidonic acid (ARA) percentage in the cerebellum and total ARA in the hippocampus. Conclusions: HF enhanced brain development in the neonatal piglet measured by brain volume and WM volume in specific brain regions; however, more studies are needed to assess long-term outcomes.
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Affiliation(s)
- Megan P Caputo
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Animal Sciences, University of Illinois, Urbana, IL, United States
| | - Jennifer N Williams
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Animal Sciences, University of Illinois, Urbana, IL, United States
| | - Jenny Drnevich
- High Performance Biological Computing Group and the Carver Biotechnology Center, University of Illinois, Urbana, IL, United States
| | - Emily C Radlowski
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Animal Sciences, University of Illinois, Urbana, IL, United States
| | - Ryan J Larsen
- Beckman Institute, University of Illinois, Urbana, IL, United States
| | - Bradley P Sutton
- Beckman Institute, University of Illinois, Urbana, IL, United States.,Department of Bioengineering, University of Illinois, Urbana, IL, United States
| | - Brian J Leyshon
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Animal Sciences, University of Illinois, Urbana, IL, United States
| | - Jamal Hussain
- Department of Food Science and Human Nutrition, University of Illinois, Urbana, IL, United States
| | - Manabu T Nakamura
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Food Science and Human Nutrition, University of Illinois, Urbana, IL, United States
| | - Matthew J Kuchan
- Abbott Nutrition, Discovery Research, Columbus, OH, United States
| | - Tapas Das
- Abbott Nutrition, Discovery Research, Columbus, OH, United States
| | - Rodney W Johnson
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.,Department of Animal Sciences, University of Illinois, Urbana, IL, United States.,Neuroscience Program, University of Illinois, Urbana, IL, United States
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Kumar G, Kasiviswanathan U, Mukherjee S, Kumar Mahto S, Sharma N, Patnaik R. Changes in electrolyte concentrations alter the impedance during ischemia-reperfusion injury in rat brain. Physiol Meas 2019; 40:105004. [DOI: 10.1088/1361-6579/ab47ee] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Nadeau CA, Dietrich K, Wilkinson CM, Crawford AM, George GN, Nichol HK, Colbourne F. Prolonged Blood-Brain Barrier Injury Occurs After Experimental Intracerebral Hemorrhage and Is Not Acutely Associated with Additional Bleeding. Transl Stroke Res 2018; 10:287-297. [PMID: 29949086 PMCID: PMC6526148 DOI: 10.1007/s12975-018-0636-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/07/2018] [Accepted: 06/04/2018] [Indexed: 01/27/2023]
Abstract
Intracerebral hemorrhage (ICH) causes blood-brain barrier (BBB) damage along with altered element levels in the brain. BBB permeability was quantified at 3, 7, and 14 days with Evans Blue dye after collagenase-induced ICH in rat. At peak permeability (day 3), a gadolinium (Gd)-based contrast agent was injected to further characterize BBB disruption, and X-ray fluorescence imaging (XFI) was used to map Gd, Fe, Cl, and other elements. XFI revealed that Ca, Cl, Gd, and Fe concentrations were significantly elevated, whereas K was significantly decreased. Therefore, using Gd-XFI, we co-determined BBB dysfunction with alterations in the metallome, including those that contribute to cell death and functional outcome. Warfarin was administered 3 days post-ICH to investigate whether additional or new bleeding occurs during peak BBB dysfunction, and hematoma volume was assessed on day 4. Warfarin administration prolonged bleeding time after a peripheral cut-induced bleed, but warfarin did not worsen hematoma volume. Accordingly, extensive BBB leakage occurred after ICH, but did not appear to affect total hematoma size.
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Affiliation(s)
- Colby A Nadeau
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada
| | - Kristen Dietrich
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Cassandra M Wilkinson
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada
| | - Andrew M Crawford
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | - Helen K Nichol
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Canada
| | - Frederick Colbourne
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada. .,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
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Barros-Barbosa AR, Fonseca AL, Guerra-Gomes S, Ferreirinha F, Santos A, Rangel R, Lobo MG, Correia-de-Sá P, Cordeiro JM. Up-regulation of P2X7 receptor-mediated inhibition of GABA uptake by nerve terminals of the human epileptic neocortex. Epilepsia 2015; 57:99-110. [PMID: 26714441 DOI: 10.1111/epi.13263] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2015] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Thirty percent of patients with epilepsy are refractory to medication. The majority of these patients have mesial temporal lobe epilepsy (MTLE). This prompts for new pharmacologic targets, like ATP-mediated signaling pathways, since the extracellular levels of the nucleotide dramatically increase during in vitro epileptic seizures. In this study, we investigated whether sodium-dependent high-affinity γ-aminobutyric acid (GABA) and glutamate uptake by isolated nerve terminals of the human neocortex could be modulated by ATP acting via slow-desensitizing P2X7 receptor (P2X7R). METHODS Modulation of [(3) H]GABA and [(14) C]glutamate uptake by ATP, through activation of P2X7R, was investigated in isolated nerve terminals of the neocortex of cadaveric controls and patients with drug-resistant epilepsy (non-MTLE or MTLE) submitted to surgery. Tissue density and distribution of P2X7R in the human neocortex was assessed by Western blot analysis and immunofluorescence confocal microscopy. RESULTS The P2X7R agonist, 2'(3')-O-(4-benzoylbenzoyl)ATP (BzATP, 3-100 μm) decreased [(3) H]GABA and [(14) C]glutamate uptake by nerve terminals of the neocortex of controls and patients with epilepsy. The inhibitory effect of BzATP (100 μm) was prevented by the selective P2X7R antagonist, A-438079 (3 μm). Down-modulation of [(14) C]glutamate uptake by BzATP (100 μm) was roughly similar in controls and patients with epilepsy, but the P2X7R agonist inhibited more effectively [(3) H]GABA uptake in the epileptic tissue. Neocortical nerve terminals of patients with epilepsy express higher amounts of the P2X7R protein than control samples. SIGNIFICANCE High-frequency cortical activity during epileptic seizures releases huge amounts of ATP, which by acting on low-affinity slowly desensitizing ionotropic P2X7R, leads to down-modulation of neuronal GABA and glutamate uptake. Increased P2X7R expression in neocortical nerve terminals of patients with epilepsy may, under high-frequency firing, endure GABA signaling and increase GABAergic rundown, thereby unbalancing glutamatergic neuroexcitation. This study highlights the relevance of the ATP-sensitive P2X7R as an important negative modulator of GABA and glutamate transport and prompts for novel antiepileptic therapeutic targets.
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Affiliation(s)
- Aurora R Barros-Barbosa
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Ana L Fonseca
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Sónia Guerra-Gomes
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Agostinho Santos
- Serviço de Patologia Forense, Instituto Nacional de Medicina Legal e Ciências Forenses - Delegação do Norte (INMLCF-DN), Porto, Portugal
| | - Rui Rangel
- Serviço de Neurocirurgia, Centro Hospitalar do Porto - Hospital Geral de Santo António (CHP - HGSA), Porto, Portugal
| | - M Graça Lobo
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - J Miguel Cordeiro
- Laboratório de Farmacologia e Neurobiologia - Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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