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BACKGROUND: Multiple Sclerosis (MS) is a chronic autoimmune, inflammatory neurological disease of the CNS. Riluzole and dimethyl fumarate (DMF) are two FDA-approved drugs to treat amyotrophic lateral sclerosis (ALS) and MS. Riluzole (a benzothiazole derivative) inhibits glutamate release from nerve terminals by antagonizing the N-Methyl-D-Aspartate (NMDA) receptor, and DMF upregulates anti-oxidative pathways. OBJECTIVES: Herein, using molecular hybridization strategy, we synthesized some new hybrid structures of Riluzole and DMF through some common successive synthetic pathways for evaluating their potential activity for remyelination in MS treatment. METHODS: Molecular docking experiments assessed the binding affinity of proposed structures to the NMDA active site. The designed structures were synthesized and purified based on well-known chemical synthesis procedures. Afterward, in vivo evaluation for their activity was done in the C57Bl/6 Cuprizone-induced demyelination MS model. RESULTS AND CONCLUSION: The proposed derivatives were recognized to be potent enough based on docking studies (ΔGbind of all derivatives were -7.2 to -7.52 compare to the Ifenprodil (-6.98) and Riluzole (-4.42)). The correct structures of desired derivatives were confirmed using spectroscopic methods. Based on in vivo studies, D4 and D6 derivatives exhibited the best pharmacological results, although only D6 showed a statistically significant difference compared to the control. Also, for D4 and D6 derivatives, myelin staining confirmed reduced degeneration in the corpus callosum. Consequently, D4 and D6 derivatives are promising candidates for developing new NMDA antagonists with therapeutic value against MS disorders.
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Synaptic dysfunction and disrupted communication between neuronal and glial cells play an essential role in the underlying mechanisms of multiple sclerosis (MS). Earlier studies have revealed the importance of glutamate receptors, particularly the N-methyl-D-aspartate (NMDA) receptor, in excitotoxicity, leading to abnormal synaptic transmission and damage of neurons. Our study aimed to determine whether antibodies to the NR2 subunit of NMDAR are detected in MS patients and evaluate the correlation between antibody presence and clinical outcome. Furthermore, our focus extended to examine a possible link between NR2 reactivity and anti-coagulant antibody levels as pro-inflammatory molecules associated with MS. A cross-sectional study was carried out, including 95 patients with MS and 61 age- and gender-matched healthy controls (HCs). The enzyme-linked immunosorbent assay was used to detect anti-NR2 antibodies in serum samples of participants along with IgG antibodies against factor (F)VIIa, thrombin, prothrombin, FXa, and plasmin. According to our results, significantly elevated levels of anti-NR2 antibodies were detected in MS patients compared to HCs (p < 0.05), and this holds true when we compared the Relapsing-Remitting MS course with HCs (p < 0.05). A monotonically increasing correlation was found between NR2 seropositivity and advanced disability (rs = 0.30; p < 0.01), anti-NR2 antibodies and disease worsening (rs = 0.24; p < 0.05), as well as between antibody activity against NR2 and thrombin (rs = 0.33; p < 0.01). The presence of anti-NR2 antibodies in MS patients was less associated with anti-plasmin IgG antibodies [OR:0.96 (95%CI: 0.92-0.99); p < 0.05]; however, such an association was not demonstrated when analyzing only RRMS patients. In view of our findings, NR2-reactive antibodies may play, paving the way for further research into their potential as biomarkers and therapeutic targets in MS.
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Receptores de N-Metil-D-Aspartato , Trombina , Humanos , Estudios Transversales , Inmunoglobulina G , Biomarcadores , AutoanticuerposRESUMEN
Balanced anesthesia relies on the simultaneous administration of different drugs to attain an anesthetic state. The classic triad of anesthesia is a combination of a hypnotic, an analgesic, and a neuromuscular blocker. It is predominantly the analgesic pillar of this triad that became more and more supported by adjuvant therapy. The aim of this approach is to evolve into an opioid-sparing technique to cope with undesirable side effects of the opioids and is fueled by the opioid epidemic. The optimal strategy for balanced general anesthesia in ambulatory surgery must aim for a transition to a multimodal analgesic regimen dealing with acute postoperative pain and ideally reduce the most common adverse effects patients are faced with at home; sore throat, delayed awakening, memory disturbances, headache, nausea and vomiting, and negative behavioral changes. Over the years, this continuum of "multimodal general anesthesia" adopted many drugs with different modes of action. This review focuses on the most recent evidence on the different adjuvants that entered clinical practice and gives an overview of the different mechanisms of action, the potential as opioid-sparing or hypnotic-sparing drugs, and the applicability specifically in ambulatory surgery.
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Anestesia Balanceada , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Humanos , Procedimientos Quirúrgicos Ambulatorios/efectos adversos , Analgésicos Opioides/efectos adversos , Anestesia General/efectos adversos , Hipnóticos y SedantesRESUMEN
Resumen Introducción: Las encefalitis inmunomediadas son un desorden neurológico de origen autoinmune. Actual mente es escasa la descripción de las secuelas cognitivas crónicas. El objetivo del presente trabajo fue caracterizar la secuela cognitiva de diferentes tipos de encefalitis inmunomediadas en una cohorte de un centro único de Argentina. Métodos: Estudio prospectivo, observacional, trans versal, de pacientes en seguimiento en un hospital de la Ciudad de Buenos Aires, con diagnóstico de encefalitis inmunomediada probable y definitiva. Se evaluaron variables epidemiológicas, clínicas, paraclínicas y tra tamiento. Se determinó la secuela cognitiva a través de una evaluación neurocognitiva realizada a partir del año de la presentación clínica. Resultados: Fueron incluidos 15 pacientes, todos con resultado disminuido en al menos un test. La memoria fue el dominio más afectado. Aquellos que se encon traban bajo tratamiento inmunosupresor al momento de evaluarse presentaron menores resultados en el aprendizaje seriado (media -2.94; desvío estándar 1.54) versus los que se encontraban sin tratamiento (media -1.18; desvío estándar 1.40; p = 0.05) y en la prueba de reconocimiento (media -10.34; desvío estándar 8.02) ver sus sin tratamiento (media -1.39; desvío estándar 2.21; p = 0.003). Los pacientes con estatus epiléptico tuvieron resultados deficitarios en la prueba de reconocimiento (media -7.2; desvío estándar 7.91) en comparación a los que no lo tenían (media -1.47; desvío estándar 2.34; p = 0.05). Conclusión: Nuestros resultados demuestran que, a pesar del curso monofásico de la enfermedad, todos los pacientes presentan daño cognitivo persistente más allá del año del inicio del cuadro. Estudios prospectivos de mayor envergadura serían necesarios para confirmar nuestros hallazgos.
Abstract Introduction: Autoimmune encephalitis represents a group of immune-mediated neurological disorders. At present, the description of the chronic cognitive sequela is scarce. The objective of this study was to characterize the cognitive after effects of different types of autoimmune encephalitis in a cohort from a single center in Argentina. Methods: Prospective, observational, cross-sectional study of patients under follow-up at a hospital in Buenos Aires city, with a diagnosis of probable and definitive immune-mediated encephalitis. Epidemiological, clini cal, paraclinical and treatment related variables were evaluated. Cognitive sequela was determined through a neurocognitive evaluation performed at least a year after the clinical presentation. Results: Fifteen patients were included. All had di minished results in at least one test. Memory was the most affected domain. Patients who were under im munosuppressive treatment at the time of evaluation presented lower results in serial learning (mean -2.94; standard deviation 1.54) versus those who weren't under treatment (mean -1.18; standard deviation 1.40; p = 0.05). The same pattern was observed on the recognition test of treatment group (mean -10.34; standard deviation 8.02) versus treatment-free group (mean -1.39; standard deviation 2.21; p =0.003). Patients with status epilepticus had poorer results in the recognition test (mean -7.2; standard deviation 7.91) compared to those without it (mean -1.47; standard deviation 2.34; p = 0.05). Conclusion: Our results show that, despite the mo nophasic course of this disease, all patients had persis tent cognitive damage beyond the year of onset. Larger prospective studies are required to confirm our findings.
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GluN2B subunit-containing N-methyl-d-aspartate (NMDA) receptors have been implicated in various neurological disorders. Nonetheless, a validated fluorine-18 labeled positron emission tomography (PET) ligand for GluN2B imaging in the living human brain is currently lacking. As part of our PET ligand development program, we have recently reported on the preclinical evaluation of [18F]OF-NB1 - a GluN2B PET ligand with promising attributes for potential clinical translation. However, the further development of [18F]OF-NB1 is currently precluded by major limitations in the radiolabeling procedure. These limitations include the use of highly corrosive reactants and racemization during the radiosynthesis. As such, the aim of this study was to develop a synthetic approach that allows an enantiomerically pure radiosynthesis of (R)-[18F]OF-NB1 and (S)-[18F]OF-NB1, as well as to assess their in vitro and in vivo performance characteristics for imaging the GluN2B subunit-containing NMDA receptor in rodents. A two-step radiosynthesis involving radiofluorination of the boronic acid pinacol ester, followed by coupling to the 3-benzazepine core structure via reductive amination was employed. The new synthetic approach yielded enantiomerically pure (R)-[18F]OF-NB1 and (S)-[18F]OF-NB1, while concurrently circumventing the use of corrosive reactants. In vitro autoradiograms with mouse and rat brain sections revealed a higher selectivity of (R)-[18F]OF-NB1 over (S)-[18F]OFNB1 for GluN2B-rich brain regions. In concert with these observations, blockade studies with commercially available GluN2B antagonist, CP101606, showed a significant signal reduction, which was more pronounced for (R)-[18F]OF-NB1 than for (S)-[18F]OF-NB1. Conversely, blockade experiments with sigma2 ligand, FA10, did not result in a significant reduction of tracer binding for both enantiomers. PET imaging experiments with CD1 mice revealed a higher brain uptake and retention for (R)-[18F]OF-NB1, as assessed by visual inspection and volumes of distribution from Logan graphical analyses. In vivo blocking experiments with sigma2 ligand, FA10, did not result in a significant reduction of the brain signal for both enantiomers, thus corroborating the selectivity over sigma2 receptors. In conclusion, we have developed a novel synthetic approach that is suitable for upscale to human use and allows the enantiomerically pure radiosynthesis of (R)-[18F]OF-NB1 and (S)-[18F]OF-NB1. While both enantiomers were selective over sigma2 receptors in vitro and in vivo, (R)-[18F]OF-NB1 showed superior GluN2B subunit specificity by in vitro autoradiography and higher volumes of distribution in small animal PET studies.
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N-methyl-D-aspartate receptors (NMDARs) are widely distributed in the central nervous system (CNS) and play critical roles in neuronal excitability in the CNS. Both clinical and preclinical studies have revealed that the abnormal expression or function of these receptors can underlie the pathophysiology of seizure disorders and epilepsy. Accordingly, NMDAR modulators have been shown to exert anticonvulsive effects in various preclinical models of seizures, as well as in patients with epilepsy. In this review, we provide an update on the pathologic role of NMDARs in epilepsy and an overview of the NMDAR antagonists that have been evaluated as anticonvulsive agents in clinical studies, as well as in preclinical seizure models.
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We present a unique case of a 28-year-old female patient admitted to our hospital due to altered mental status, hallucinations, agitation, impaired memory, and impaired speech. The patient had a previous psychiatric admission to another hospital but she was discharged without a definitive diagnosis. During her admission, the majority of the medical staff was under the impression she was having a psychotic event. The patient was subsequently diagnosed with N-methyl-D-aspartate receptor (NMDAR) encephalitis. Our aim is to report the clinical approach to diagnose and manage a type of autoimmune encephalitis associated with ovarian teratomas, but most importantly to teach and make awareness in the medical community of how to recognize this type of encephalitis.
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N-methyl-D-aspartate (NMDA) receptors play a critical role in activity-dependent dendritic arborization, spinogenesis, and synapse formation by stimulating calcium-dependent signaling pathways. Previously, we have shown that brevetoxin 2 (PbTx-2), a voltage-gated sodium channel (VGSC) activator, produces a concentration-dependent increase in intracellular sodium [Na+]I and increases NMDA receptor (NMDAR) open probabilities and NMDA-induced calcium (Ca2+) influxes. The objective of this study is to elucidate the downstream signaling mechanisms by which the sodium channel activator PbTx-2 influences neuronal morphology in murine cerebrocortical neurons. PbTx-2 and NMDA triggered distinct Ca2+-influx pathways, both of which involved the NMDA receptor 2B (GluN2B). PbTx-2-induced neurite outgrowth in day in vitro 1 (DIV-1) neurons required the small Rho GTPase Rac1 and was inhibited by both a PAK1 inhibitor and a PAK1 siRNA. PbTx-2 exposure increased the phosphorylation of PAK1 at Thr-212. At DIV-5, PbTx-2 induced increases in dendritic protrusion density, p-cofilin levels, and F-actin throughout the dendritic arbor and soma. Moreover, PbTx-2 increased miniature excitatory post-synaptic currents (mEPSCs). These data suggest that the stimulation of neurite outgrowth, spinogenesis, and synapse formation produced by PbTx-2 are mediated by GluN2B and PAK1 signaling.
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Neuronas , Receptores de N-Metil-D-Aspartato , Quinasas p21 Activadas , Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Animales , Calcio/metabolismo , Toxinas Marinas , Ratones , N-Metilaspartato , Proyección Neuronal , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Oxocinas , ARN Interferente Pequeño/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sodio/metabolismo , Agonistas de los Canales de Sodio/metabolismo , Canales de Sodio Activados por Voltaje/metabolismo , Quinasas p21 Activadas/metabolismo , Proteínas de Unión al GTP rho/metabolismoRESUMEN
Attention-deficit/hyperactivity disorder (AD/HD) is a mild neurodevelopmental disorder with inattention, hyperactivity, and impulsivity as its core symptoms. We previously revealed that an AD/HD animal model, juvenile stroke-prone spontaneously hypertensive rats (SHRSP/Ezo) exhibited functional abnormalities in N-methyl-D-aspartate (NMDA) receptors in the prefrontal cortex. D-serine is an endogenous co-ligand that acts on the glycine-binding site of NMDA receptors, which is essential for the physiological activation of NMDA receptors. We herein performed neurochemical and pharmacological behavioral experiments to elucidate dysfunctions in D-serine metabolism (namely, biosynthesis and catabolism) associated to AD/HD. The serine enantiomers ratio (D-serine/D-serine + L-serine, DL ratio) in the medial prefrontal cortex (mPFC) and hippocampus (HIP) was lower in SHRSP/Ezo than in its genetic control. The level of D-amino acid oxidase (DAAO, D-serine degrading enzyme) was higher in the mPFC, and the level of serine racemase (SR, D-serine biosynthetic enzyme), was lower in the HIP in SHRSP/Ezo. Thus, changes in these enzymes may contribute to the lower DL ratio of SHRSP/Ezo. Moreover, a microinjection of a DAAO inhibitor into the mPFC in SHRSP/Ezo increased DL ratio and attenuated AD/HD-like behaviors, such as inattention and hyperactivity, in the Y-maze test. Injection into the HIP also increased the DL ratio, but had no effect on behaviors. These results suggest that AD/HD-like behaviors in SHRSP/Ezo are associated with an abnormal D-serine metabolism underlying NMDA receptor dysfunction in the mPFC. These results will contribute to elucidating the pathogenesis of AD/HD and the development of new treatment strategies for AD/HD.
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Trastorno por Déficit de Atención con Hiperactividad , Animales , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Modelos Animales de Enfermedad , Hipocampo/metabolismo , Corteza Prefrontal/metabolismo , Ratas , Ratas Endogámicas SHR , Receptores de N-Metil-D-Aspartato/metabolismo , Serina/metabolismoRESUMEN
Introduction: For more than a decade, NMDAR autoimmune encephalitis has been studied and treated as a neurological condition, and good results have been achieve through immune therapies. Apart from being well represented in the CNS, NMDA receptors are currently known of and being studied in multiple non-neuronal cells with potential clinical significance. The association of NMDAR autoimmune encephalitis with pregnancy is rare, and hypokalemia is not mentioned. Methods: We present the case of a 30-year-old woman with NMDAR autoimmune encephalitis in her 17th week of pregnancy associated with persistent hypokalemia that had no apparent cause and resisted Kalium chloride supplementation. A diagnostic work-up including clinical, laboratory, and imagistic examinations, was performed. The case was monitored between May and September 2016 at Neurology, SCJUT. Results: Severe hypokalemia with normal serum sodium levels persisted throughout the course of clinical manifestation of anti-NMDAR autoimmune encephalitis. Conclusions: NMDAR autoimmune encephalitis is under-diagnosed in its atypical clinical variants, and this disease's association with hypokalemia is not mentioned in the literature. Still, it is of clinical importance because it attests to the implications of other organs/systems in the general autoimmune process of NMDAR encephalitis, and it might change the way we address certain psychiatric disorders by searching underlying organic conditions.
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AIMS: Soticlestat, a first-in-class inhibitor of cholesterol 24-hydroxylase (also known as cytochrome P450 46A1), is currently in development for the treatment of developmental and epileptic encephalopathies. Here, we report safety, tolerability, pharmacokinetic and pharmacodynamic outcomes from a phase I, randomized, double-blind, placebo-controlled, multiple-rising-dose study of soticlestat in healthy adults. METHODS: Five cohorts of healthy subjects (n = 8 each, randomized 6:2 soticlestat:placebo) received oral soticlestat 100-600 mg once daily (QD) or 300 mg twice daily (BID) for 10-14 days. Serial blood and urine samples were obtained on days 1, 7 (blood only) and 14. RESULTS: Soticlestat in the dose range 100-400 mg/day for up to 14 days was generally well tolerated. In total, 45 treatment-emergent adverse events (TEAEs) were reported; most (91%) were transient and mild in intensity. Two subjects experienced TEAEs leading to discontinuation: one receiving soticlestat 600 mg QD reported a severe event of acute psychosis; another receiving 300 mg BID reported a mild event of confusional state. Steady-state exposure to soticlestat increased in a slightly greater than dose-proportional manner across the dose range 100-400 mg QD. Peak plasma concentrations were reached within 0.33-0.5 hour, and soticlestat elimination half-life was approximately 4 hours. Renal excretion of soticlestat was negligible. Soticlestat 100-400 mg QD reduced 24S-hydroxycholesterol levels by 46.8 (coefficient of variation [CV%] -9.2) to -62.7% (CV% -7.3) at steady state; values of enzymatic inhibition were compatible with antiepileptic effects observed in preclinical models. CONCLUSION: The pharmacokinetic and pharmacodynamic profiles of soticlestat characterized here provided a data-driven rationale for clinical trial dose selection.
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Piperidinas , Piridinas , Adulto , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Voluntarios Sanos , HumanosRESUMEN
Stemming from the results of the historic STAR-D trial, it is evident that a significant subset of individuals (20-25%) with major depressive disorder (MDD) do not respond to conventional antidepressant medications. As a result, an emphasis has been placed on the development of novel therapeutics for MDD over the last two decades. Recently, substantial research efforts have been focused on the use of ketamine as an antidepressant whose mechanism of action is via the N-methyl-d-aspartate (NMDA) receptor. Another potential therapeutic compound of interest is nitrous oxide, which has been utilized for more than a century in multiple fields of medicine for its analgesic and anesthetic properties. Recent clinical studies suggest that nitrous oxide may be effective for treatment-resistant depression. In this review, we will discuss the administration of nitrous oxide as a psychiatric intervention, current use in psychiatry, putative mechanisms of action, and future directions highlighting knowledge gaps and other potential utilities in the field of psychiatry.
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Trastorno Depresivo Mayor , Trastorno Depresivo Resistente al Tratamiento , Antidepresivos/farmacología , Antidepresivos/uso terapéutico , Depresión/tratamiento farmacológico , Trastorno Depresivo Mayor/tratamiento farmacológico , Trastorno Depresivo Resistente al Tratamiento/tratamiento farmacológico , Humanos , Óxido Nitroso/uso terapéuticoRESUMEN
Among the myriad of cellular and molecular processes identified as contributing to pathological pain, disinhibition of spinal cord nociceptive signaling to higher cortical centers plays a critical role. Importantly, evidence suggests that impaired glycinergic neurotransmission develops in the dorsal horn of the spinal cord in inflammatory and neuropathic pain models and is a key maladaptive mechanism causing mechanical hyperalgesia and allodynia. Thus, it has been hypothesized that pharmacological agents capable of augmenting glycinergic tone within the dorsal horn may be able to blunt or block aberrant nociceptor signaling to the brain and serve as a novel class of analgesics for various pathological pain states. Indeed, drugs that enhance dysfunctional glycinergic transmission, and in particular inhibitors of the glycine transporters (GlyT1 and GlyT2), are generating widespread interest as a potential class of novel analgesics. The GlyTs are Na+/Cl--dependent transporters of the solute carrier 6 (SLC6) family and it has been proposed that the inhibition of them presents a possible mechanism by which to increase spinal extracellular glycine concentrations and enhance GlyR-mediated inhibitory neurotransmission in the dorsal horn. Various inhibitors of both GlyT1 and GlyT2 have demonstrated broad analgesic efficacy in several preclinical models of acute and chronic pain, providing promise for the approach to deliver a first-in-class non-opioid analgesic with a mechanism of action differentiated from current standard of care. This review will highlight the therapeutic potential of GlyT inhibitors as a novel class of analgesics, present recent advances reported for the field, and discuss the key challenges associated with the development of a GlyT inhibitor into a safe and effective agent to treat pain.
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Dolor Crónico , Glicina/metabolismo , Neuralgia , Nocicepción , Transducción de Señal , Médula Espinal/metabolismo , Transmisión Sináptica , Animales , Dolor Crónico/metabolismo , Dolor Crónico/patología , Dolor Crónico/terapia , Proteínas de Transporte de Glicina en la Membrana Plasmática/metabolismo , Humanos , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , Neuralgia/patología , Médula Espinal/patologíaRESUMEN
We previously generated an ischemic stroke in a zebrafish model using N2 gas perfusion; however, this model was an unsuitable drug screening system due to low throughput. In this study, we examined a zebrafish ischemic stroke model using an oxygen absorber to assess drug effects. Hypoxic exposure more than 2 h using the oxygen absorber significantly induced cell death in the brain and damage to the neuronal cells. To confirm the utility of the ischemic model induced by the oxygen absorber, we treated zebrafish with neuroprotective agents. MK-801, an N-methyl-d-aspartate (NMDA) receptor antagonist, significantly suppressed cell death in the brain, and edaravone, a free radical scavenger, significantly reduced the number of dead cells. These results suggest that the activation of NMDA receptors and the production of reactive oxygen species induce neuronal cell damage in accordance with previous mammalian reports. We demonstrate the suitability of an ischemic stroke model in zebrafish larvae using the oxygen absorber, enabling a high throughput drug screening.
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Isquemia Encefálica/tratamiento farmacológico , Maleato de Dizocilpina/uso terapéutico , Evaluación Preclínica de Medicamentos/métodos , Edaravona/uso terapéutico , Depuradores de Radicales Libres/uso terapéutico , Larva , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Pez Cebra , Animales , Encéfalo/patología , Isquemia Encefálica/etiología , Isquemia Encefálica/patología , Muerte Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Maleato de Dizocilpina/farmacología , Edaravona/farmacología , Depuradores de Radicales Libres/farmacología , Gases , Hipoxia/complicaciones , Hipoxia/patología , Neuronas/patología , NitrógenoRESUMEN
BACKGROUND: Achyranthes bidentata polypeptides (ABPPs) are a potent intervention for excitotoxicity-related disorders such as Parkinson's disease and ischemic stroke. Previous work suggests that overstimulation of N-methyl-D-aspartate (NMDA) receptors plays a critical role in excitotoxicity, and expression of NR2 subunit variations is developmentally regulated. Our current study focused on neuroprotection of ABPPs on cultured neurons by modulation of NR2A and NR2B differentially. METHODS: Primary cultured neurons were treated with NVP-AAM077, Ro-256981, ABPPs, and then the neurons were exposed to NMDA to induce excitotoxicity. Cellular viability was detected promptly and 24-hour after exposure to NMDA by MTT assay. Patch-clamp recording was applied to evaluate the effect of ABPPs on NMDA-evoked current and the differential modulation of ABPPs on NR2A and NR2B subunits in conjunction with NVP-AAM077 and Ro-256981. RESULTS: ABPPs (10 µg/mL) blocked neuronal injury by NMDA in mature cultures, and the peptides conferred neuroprotection in immature cultures unless co-applied with NVP-AAM077. Furthermore, ABPPs enhanced NMDA current in mature cultures, while decreasing NMDA current in immature cultures. On the other hand, we showed that ABPPs increased NMDA current when Ro-256981 was present and decreased NMDA current when NVP-AAM007 was present. CONCLUSIONS: Neuroprotection of ABPPs on NMDA-mediated injury differentially in immature and mature cultures involves enhancement of NR2A subunits and prevention of NR2B subunits, indicating that dosage of ABPP should be considered in treatment with patients at different developmental stages.
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Although stroke is very often the cause of death worldwide, the burden of ischemic and hemorrhagic stroke varies between regions and over time regarding differences in prognosis, prevalence of risk factors, and treatment strategies. Excitotoxicity, oxidative stress, dysfunction of the blood-brain barrier, neuroinflammation, and lysosomal membrane permeabilization, sequentially lead to the progressive death of neurons. In this process, protein kinases-related checkpoints tightly regulate N-methyl-D-aspartate (NMDA) receptor signaling pathways. One of the major hallmarks of cerebral ischemia is excitotoxicity, characterized by overactivation of glutamate receptors leading to intracellular Ca2+ overload and ultimately neuronal death. Thus, reduced expression of postsynaptic density-95 protein and increased protein S-nitrosylation in neurons is responsible for neuronal vulnerability in cerebral ischemia. In this chapter death-associated protein kinases, cyclin-dependent kinase 5, endoplasmic reticulum stress-induced protein kinases, hyperhomocysteinemia-related NMDA receptor overactivation, ephrin-B-dependent amplification of NMDA-evoked neuronal excitotoxicity and lysosomocentric hypothesis have been discussed.Consequently, ample evidences have demonstrated that enhancing extrasynaptic NMDA receptor activity triggers cell death after stroke. In this context, considering the dual roles of NMDA receptors in both promoting neuronal survival and mediating neuronal damage, selective augmentation of NR2A-containing NMDA receptor activation in the presence of NR2B antagonist may constitute a promising therapy for stroke.
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Isquemia Encefálica , Receptores de N-Metil-D-Aspartato , Muerte Celular , Humanos , Neuronas , Proteínas QuinasasRESUMEN
Atherosclerosis is a chronic cardiovascular disease and contributes to pathogenesis of most myocardial infarction and ischemic stroke. Additionally, N-methyl-D-aspartate (NMDA) receptor plays a crucial role in myocardial infarction and ischemic strokes. The aim of our study was to investigate the underlying mechanisms of memantine (MEM), the blocker of NMDA receptors, in the development of atherosclerosis. In our study, human umbilical vascular endothelial cells (HUVECs) were stimulated with low-density lipoprotein (ox-LDL) to establish an atherosclerotic cell model. Cell Counting Kit-8 (CCK-8) assay and TUNEL staining were performed to detect the cell activity and apoptosis of HUVECs, respectively. The levels of inflammatory cytokines and malondialdehyde and the activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and caspase-1 were quantified with commercial assay kits. Finally, qRT-PCR assay and western blot analysis were carried out to determine the mRNA and protein expressions of inflammation-related genes in HUVECs. The results of the present study suggested that ox-LDL stimulation induced decreased viability of HUVECs, excessive inflammation, and oxidative stress, while these effects were counteracted by MEM treatment. Interestingly, MEM triggered the activation of BDNF/TrkB signaling pathway in HUVECs, and K252a, the inhibitor of the BDNF/TrkB pathway, abolished the suppressive effect of MEM on ox-LDL-induced inflammation, oxidative stress, and apoptosis in HUVECs. Overall, MEM attenuated ox-LDL-induced inflammation, oxidative stress, and apoptosis via activation of BDNF/TrkB signaling pathway in HUVECs, indicating that MEM may be defined as a novel and effective agent for atherosclerosis treatment.
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Aterosclerosis/tratamiento farmacológico , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Antagonistas de Aminoácidos Excitadores/farmacología , Inflamación/tratamiento farmacológico , Memantina/farmacología , Glicoproteínas de Membrana/metabolismo , Estrés Oxidativo/efectos de los fármacos , Receptor trkB/metabolismo , Apoptosis/efectos de los fármacos , Aterosclerosis/etiología , Aterosclerosis/metabolismo , Biomarcadores/metabolismo , Western Blotting , Células Cultivadas , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Antagonistas de Aminoácidos Excitadores/uso terapéutico , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Etiquetado Corte-Fin in Situ , Inflamación/etiología , Inflamación/metabolismo , Lipoproteínas LDL , Memantina/uso terapéutico , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/efectos de los fármacosRESUMEN
Perfluoroalkyl acids (PFAAs) are persistent man-made chemicals, ubiquitous in nature and present in human samples. Although restrictions are being introduced, they are still used in industrial processes as well as in consumer products. PFAAs cross the blood-brain-barrier and have been observed to induce adverse neurobehavioural effects in humans and animals as well as adverse effects in neuronal in vitro studies. The sulfonated PFAA perfluorooctane sulfonic acid (PFOS), has been shown to induce excitotoxicity via the N-methyl-D-aspartate receptor (NMDA-R) in cultures of rat cerebellar granule neurons (CGNs). In the present study the aim was to further characterise PFOS-induced toxicity (1-60 µM) in rat CGNs, by examining interactions between PFOS and elements of glutamatergic signalling and excitotoxicity. Effects of the carboxylated PFAA, perfluorooctanoic acid (PFOA, 300-500 µM) on the same endpoints were also examined. During experiments in immature cultures at days in vitro (DIV) 8, PFOS increased both the potency and efficacy of glutamate, whereas in mature cultures at DIV 14 only increased potency was observed. PFOA also increased potency at DIV 14. PFOS-enhanced glutamate toxicity was further antagonised by the competitive NMDA-R antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) at DIV 8. At DIV 8, PFOS also induced glutamate release (9-13 fold increase vs DMSO control) after 1-3 and 24 h exposure, whereas for PFOA a large (80 fold) increase was observed, but only after 24 h. PFOS and PFOA both also increased alanine and decreased serine levels after 24 h exposure. In conclusion, our results indicate that PFOS at concentrations relevant in an occupational setting, may be inducing excitotoxicity, and potentiation of glutamate signalling, via an allosteric action on the NMDA-R or by actions on other elements regulating glutamate release or NMDA-R function. Our results further support our previous findings that PFOS and PFOA at equipotent concentrations induce toxicity via different mechanisms of action.
Asunto(s)
Ácidos Alcanesulfónicos/toxicidad , Caprilatos/toxicidad , Cerebelo/efectos de los fármacos , Agonistas de Aminoácidos Excitadores/toxicidad , Fluorocarburos/toxicidad , Ácido Glutámico/toxicidad , Neuronas/efectos de los fármacos , Ácidos Alcanesulfónicos/administración & dosificación , Animales , Caprilatos/administración & dosificación , Bovinos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Cerebelo/patología , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Agonistas de Aminoácidos Excitadores/administración & dosificación , Femenino , Fluorocarburos/administración & dosificación , Ácido Glutámico/administración & dosificación , Masculino , Neuronas/patología , Ratas , Ratas WistarRESUMEN
D-amino acids have been known to exist in the human brain for nearly 40 years, and they continue to be a field of active study to today. This review article aims to give a concise overview of the recent advances in D-amino acid research as they relate to the brain and neurological disorders. This work has largely been focused on modulation of the N-methyl-D-aspartate (NMDA) receptor and its relationship to Alzheimer's disease and Schizophrenia, but there has been a wealth of novel research which has elucidated a novel role for several D-amino acids in altering brain chemistry in a neuroprotective manner. D-amino acids which have no currently known activity in the brain but which have active derivatives will also be reviewed.