RESUMO
Methamphetamine (MA) is a highly addictive drug, and MA use disorder is often comorbid with anxiety and cognitive impairment. These comorbid conditions are theorized to reflect glutamate-related neurotoxicity within the frontal cortical regions. However, our prior studies of MA-sensitized mice indicate that subchronic, behaviorally non-contingent MA treatment is sufficient to dysregulate glutamate transmission in mouse brain. Here, we extend this prior work to a mouse model of high-dose oral MA self-administration (0.8, 1.6, or 3.2 g/L; 1 h sessions × 7 days) and show that while female C57BL/6J mice consumed more MA than males, MA-experienced mice of both sexes exhibited some signs of anxiety-like behavior in a behavioral test battery, although not all effects were concentration-dependent. No MA effects were detected for our measures of visually cued spatial navigation, spatial learning, or memory in the Morris water maze; however, females with a history of 3.2 g/L MA exhibited reversal-learning deficits in this task, and mice with a history of 1.6 g/L MA committed more working-memory incorrect errors and relied upon a non-spatial navigation strategy during the radial-arm maze testing. Relative to naïve controls, MA-experienced mice exhibited several changes in the expression of certain glutamate receptor-related proteins and their downstream effectors within the ventral and dorsal areas of the prefrontal cortex, the hippocampus, and the amygdala, many of which were sex-selective. Systemic pretreatment with the mGlu1-negative allosteric modulator JNJ 162596858 reversed the anxiety-like behavior expressed by MA-experienced mice in the marble-burying test, while systemic pretreatment with NMDA or the NMDA antagonist MK-801 bi-directionally affected the MA-induced reversal-learning deficit. Taken together, these data indicate that a relatively brief history of oral MA is sufficient to induce some signs of anxiety-like behavior and cognitive dysfunction during early withdrawal that reflect, at least in part, MA-induced changes in the corticolimbic expression of certain glutamate receptor subtypes of potential relevance to treating symptoms of MA use disorder.
Assuntos
Metanfetamina , Masculino , Camundongos , Animais , Feminino , Metanfetamina/toxicidade , N-Metilaspartato/farmacologia , Camundongos Endogâmicos C57BL , Receptores de Glutamato , Ácido Glutâmico/metabolismo , Cognição , Aprendizagem em LabirintoRESUMO
BACKGROUND: Depression is a common and recurrent neuropsychiatric disorder. Recent studies have shown that the N-methyl-d-aspartate (NMDA) receptor (NMDAR) is involved in the pathophysiology of depression. Previous studies have found that Kaji-ichigoside F1 (KF1) has a protective effect against NMDA-induced neurotoxicity. However, the antidepressant mechanism of KF1 has not been confirmed yet. PURPOSE: In the present study, we aimed to evaluate the rapid antidepressant activity of KF1 and explore the underlying mechanism. STUDY DESIGN: First, we explored the effect of KF1 on NMDA-induced hippocampal neurons and the underlying mechanism. Second, depression was induced in C57BL/6 mice via chronic unpredictable mild stress (CUMS), and the immediate and persistent depression-like behavior was evaluated using the forced swimming test (FST) after a single administration of KF1. Third, the contributions of NMDA signaling to the antidepressant effect of KF1 were investigated using pharmacological interventions. Fourth, CUMS mice were treated with KF1 for 21 days, and then their depression-like behaviors and the underlying mechanism were further explored. METHODS: The FST was used to evaluate immediate and persistent depression-like behavior after a single administration of KF1 with or without NMDA pretreatment. The effect of KF1 on depressive-like behavior was investigated in CUMS mice by treating them with KF1 once daily for 21 days through the sucrose preference test, FST, open field test, and tail suspension test. Then, the effects of KF1 on the morphology and molecular and functional phenotypes of primary neuronal cells and hippocampus of mice were investigated by hematoxylin-eosin staining, Nissl staining, propidium iodide staining, TUNEL staining, Ca2+ imaging, JC-1 staining, ELISA, immunofluorescence analysis, RT-PCR, and Western blot. RESULTS: KF1 could effectively improve cellular viability, reduce apoptosis, inhibit the release of LDH and Ca2+, and increase the mitochondrial membrane potential and the number of dendritic spines numbers in hippocampal neurons. Moreover, behavioral tests showed that KF1 exerted acute and sustained antidepressant-like effects by reducing Glu-levels and ameliorating neuronal damage in the hippocampus. Additionally, in vivo and in vitro experiments revealed that PSD95, Syn1, α-amino-3hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and brain-derived neurotrophic factor (BDNF) were upregulated at the protein level, and BDNF and AMPA were upregulated at the mRNA level. NR1 and NR2A showed the opposite trend. CONCLUSION: These results confirm that KF1 exerts rapid antidepressant effects mainly by activating the AMPA-BDNF-mTOR pathway and inhibiting the NMDAR-CaMKIIα pathway. This study serves as a new reference for discovering rapid antidepressants.
Assuntos
Fator Neurotrófico Derivado do Encéfalo , Depressão , Camundongos , Animais , Depressão/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacologia , Camundongos Endogâmicos C57BL , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Serina-Treonina Quinases TOR/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Hipocampo , Estresse Psicológico/tratamento farmacológico , Modelos Animais de DoençasRESUMO
NMDA receptors (NMDARs) modulate glutamatergic excitatory tone in the brain via two complementary modalities: a phasic excitatory postsynaptic current and a tonic extrasynaptic modality. Here, we demonstrated that the tonic NMDAR-current (I NMDA) mediated by NR2A-containing NMDARs is an efficient biosensor detecting the altered ambient glutamate level in the supraoptic nucleus (SON). I NMDA of magnocellular neurosecretory cells (MNCs) measured by nonselective NMDARs antagonist, AP5, at holding potential (V holding) -70â mV in low concentration of ECF Mg2+ ([Mg2+]o) was transiently but significantly increased 1-week post induction of a DOCA salt hypertensive model rat which was compatible with that induced by a NR2A-selective antagonist, PEAQX (I PEAQX) in both DOCA-H2O and DOCA-salt groups. In agreement, NR2B antagonist, ifenprodil, or NR2C/D antagonist, PPDA, did not affect the holding current (I holding) at V holding -70â mV. Increased ambient glutamate by exogenous glutamate (10â mM) or excitatory amino acid transporters (EAATs) antagonist (TBOA, 50â mM) abolished the I PEAQX difference between two groups, suggesting that attenuated EAATs activity increased ambient glutamate concentration, leading to the larger I PEAQX in DOCA-salt rats. In contrast, only ifenprodil but not PEAQX and PPDA uncovered I NMDA at V holding +40â mV under 1.2â mM [Mg2+]o condition. I ifenprodil was not different in DOCA-H2O and DOCA-salt groups. Finally, NR2A, NR2B, and NR2D protein expression were not different in the SON of the two groups. Taken together, NR2A-containing NMDARs efficiently detected the increased ambient glutamate concentration in the SON of DOCA-salt hypertensive rats due to attenuated EAATs activity.
Assuntos
Acetato de Desoxicorticosterona , Receptores de N-Metil-D-Aspartato , Ratos , Animais , Receptores de N-Metil-D-Aspartato/metabolismo , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacologia , Ácido Glutâmico/metabolismo , Núcleo Supraóptico/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacologiaRESUMO
Hypothalamus is central to food intake and satiety. Recent data unveiled the expression of N-methyl-D-aspartate receptors (NMDAR) on hypothalamic neurons and their interaction with GABAA and serotoninergic neuronal circuits. However, the precise mechanisms governing energy homeostasis remain elusive. Notably, in females, the consumption of progesterone-containing preparations, such as hormonal replacement therapy and birth control pills, has been associated with hyperphagia and obesity-effects mediated through the hypothalamus. To elucidate this phenomenon, we employed the progesterone-induced obesity model in female Swiss albino mice. Four NMDAR modulators were selected viz. dextromethorphan (Dxt), minocycline, d-aspartate, and cycloserine. Obesity was induced in female mice by progesterone administration for 4 weeks. Mice were allocated into 7 groups, group-1 as vehicle control (arachis oil), group-2 (progesterone + arachis oil), and group-3 as positive-control (progesterone + sibutramine); other groups were treated with test drugs + progesterone. Various parameters were recorded like food intake, thermogenesis, serum lipids, insulin, AST and ALT levels, organ-to-body weight ratio, total body fat, adiposity index, brain serotonin levels, histology of liver, kidney, and sizing of fat cells. Dxt-treated group has shown a significant downturn in body weight (p < 0.05) by a decline in food intake (p < 0.01), organ-to-liver ratio (p < 0.001), adiposity index (p < 0.01), and a rise in body temperature and brain serotonin level (p < 0.001). Dxt demonstrated anti-obesity effects by multiple mechanisms including interaction with hypothalamic GABAA channels and anti-inflammatory and free radical scavenging effects, improving the brain serotonin levels, and increasing insulin release from the pancreatic ß-cells.
Assuntos
Insulinas , N-Metilaspartato , Feminino , Camundongos , Animais , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Serotonina/metabolismo , Progesterona/farmacologia , Óleo de Amendoim/metabolismo , Óleo de Amendoim/farmacologia , Óleo de Amendoim/uso terapêutico , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Hipotálamo , Insulinas/metabolismo , Insulinas/farmacologia , Insulinas/uso terapêutico , Ácido gama-AminobutíricoRESUMO
Brain damage caused by ethanol abuse may lead to permanent damage, including severe dementia. The aim of this study was to investigate the effects of ginger powder on ethanol-induced cognitive disorders by examining oxidative damage and inflammation status, and the gene expression of N-methyl-D-aspartate (NMDA) and γ-Aminobutyric acid (GABA)-A receptors in the hippocampus of male rats. 24 adult male Sprague-Dawley rats were allocated randomly to four groups as follows control, ethanol (4g/kg/day, by gavage), ginger (1g/kg/day, by gavage), and ginger-ethanol. At the end of the study, memory and learning were evaluated by the shuttle box test. Moreover, to explore mechanisms involved in ethanol-induced cognitive impairment and the protective effect of ginger, the expression of Nuclear factor kappa B (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), NMDA receptor, and GABA-A receptor was measured along with inflammatory and oxidative biomarkers in the hippocampus tissue. The results showed that ethanol could induce cognitive impairment in the ethanol group, while pretreatment with ginger could reverse it. The gene expression of the NF-κB/ Tumor necrosis factor (TNF)-α/Interleukin (IL)-1ß pathway and NMDA and GABA-A receptors significantly increased in the ethanol group compared to the control group. While pretreatment with ginger could significantly improve ethanol-induced cognitive impairment through these pathways in the ginger-ethanol group compared to the ethanol group (P < 0.05). It can be concluded that ginger powder could ameliorate ethanol-induced cognitive impairment by modulating the expression of NMDA and GABA-A receptors and inhibiting oxidative damage and the NF-κB/TNF-α/IL-1ß pathway in the rat hippocampus.
Assuntos
Disfunção Cognitiva , Zingiber officinale , Ratos , Animais , Masculino , Ratos Sprague-Dawley , Receptores de GABA-A/metabolismo , N-Metilaspartato/metabolismo , N-Metilaspartato/farmacologia , Etanol/toxicidade , NF-kappa B/metabolismo , Receptores de GABA/metabolismo , Pós/metabolismo , Pós/farmacologia , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Extratos Vegetais/metabolismo , Hipocampo/metabolismo , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The current study was designed to examine the role of glutamate NMDA receptors of the mediodorsal thalamus (MD) in scopolamine-induced memory impairment. Adult male rats were bilaterally cannulated into the MD. According to the results, intraperitoneal (i.p.) administration of scopolamine (1.5 mg/kg) immediately after the training phase (post-training) impaired memory consolidation. Bilateral microinjection of the glutamate NMDA receptors agonist, N-Methyl-D-aspartic acid (NMDA; 0.05 µg/rat), into the MD significantly improved scopolamine-induced memory consolidation impairment. Co-administration of D-AP5, a glutamate NMDA receptor antagonist (0.001-0.005 µg/rat, intra-MD) potentiated the response of an ineffective dose of scopolamine (0.5 mg/kg, i.p.) to impair memory consolidation, mimicking the response of a higher dose of scopolamine. Noteworthy, post-training intra-MD microinjections of the same doses of NMDA or D-AP5 alone had no effect on memory consolidation. Moreover, the blockade of the glutamate NMDA receptors by 0.003 ng/rat of D-AP5 prevented the improving effect of NMDA on scopolamine-induced amnesia. Thus, it can be concluded that the MD glutamatergic system may be involved in scopolamine-induced memory impairment via the NMDA receptor signaling pathway.
Assuntos
N-Metilaspartato , Escopolamina , Ratos , Masculino , Animais , Escopolamina/farmacologia , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Ácido Glutâmico/metabolismo , Ratos Wistar , Amnésia/induzido quimicamente , Transtornos da Memória/induzido quimicamente , Agonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Tálamo/metabolismo , Aprendizagem da EsquivaRESUMO
Selenium (Se) is an essential trace element required for normal development as well as to counteract the adverse effects of environmental stressors. Conditions of low Se intake are present in some European countries. Our aim was to investigate the short- and long-term effects of early-life low Se supply on behavior and synaptic plasticity with a focus on the hippocampus, considering both suboptimal Se intake per se and its interaction with developmental exposure to lead (Pb). We established an animal model of Se restriction and low Pb exposure; female rats fed with an optimal (0.15 mg/kg) or suboptimal (0.04 mg/kg) Se diet were exposed from one month pre-mating until the end of lactation to 12.5 µg/mL Pb via drinking water. In rat offspring, the assessment of motor, emotional, and cognitive endpoints at different life stages were complemented by the evaluation of the expression and synaptic distribution of NMDA and AMPA receptor subunits at post-natal day (PND) 23 and 70 in the hippocampus. Suboptimal Se intake delayed the achievement of developmental milestones and induced early and long-term alterations in motor and emotional abilities. Behavioral alterations were mirrored by a drop in the expression of the majority of NMDA and AMPA receptor subunits analyzed at PND 23. The suboptimal Se status co-occurring with Pb exposure induced a transient body weight increase and persistent anxiety-like behavior. From the molecular point of view, we observed hippocampal alterations in NMDA (Glun2B and GluN1) and AMPA receptor subunit trafficking to the post-synapse in male rats only. Our study provides evidence of potential Se interactions with Pb in the developing brain.
Assuntos
Comportamento Animal , Deficiências do Desenvolvimento , Hipocampo , Chumbo , Receptores de Glutamato , Selênio , Animais , Comportamento Animal/fisiologia , Deficiências do Desenvolvimento/etiologia , Deficiências do Desenvolvimento/metabolismo , Deficiências do Desenvolvimento/psicologia , Modelos Animais de Doenças , Ingestão de Alimentos , Feminino , Hipocampo/metabolismo , Chumbo/metabolismo , Chumbo/toxicidade , Masculino , N-Metilaspartato/farmacologia , Ratos , Receptores de AMPA/metabolismo , Receptores de Glutamato/metabolismo , Selênio/deficiência , Selênio/metabolismo , Selênio/farmacologiaRESUMO
RATIONALE: Hypertension is a common and serious adverse effect of calcineurin inhibitors, including cyclosporine and tacrolimus (FK506). Although increased sympathetic nerve discharges are associated with calcineurin inhibitor-induced hypertension, the sources of excess sympathetic outflow and underlying mechanisms remain elusive. Calcineurin (protein phosphatase-2B) is broadly expressed in the brain, including the paraventricular nuclear (PVN) of the hypothalamus, which is critically involved in regulating sympathetic vasomotor tone. OBJECTIVE: We determined whether prolonged treatment with the calcineurin inhibitor causes elevated sympathetic output and persistent hypertension by potentiating synaptic N-methyl-D-aspartate (NMDA) receptor activity in the PVN. METHODS AND RESULTS: Telemetry recordings showed that systemic administration of FK506 (3 mg/kg per day) for 14 days caused a gradual and profound increase in arterial blood pressure in rats, which lasted at least 7 days after discontinuing FK506 treatment. Correspondingly, systemic treatment with FK506 markedly reduced calcineurin activity in the PVN and circumventricular organs, but not rostral ventrolateral medulla, and increased the phosphorylation level and synaptic trafficking of NMDA receptors in the PVN. Immunocytochemistry labeling showed that calcineurin was expressed in presympathetic neurons in the PVN. Whole-cell patch-clamp recordings in brain slices revealed that treatment with FK506 increased baseline firing activity of PVN presympathetic neurons; this increase was blocked by the NMDA or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist. Also, treatment with FK506 markedly increased presynaptic and postsynaptic NMDA receptor activity of PVN presympathetic neurons. Furthermore, microinjection of the NMDA or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist into the PVN of anesthetized rats preferentially attenuated renal sympathetic nerve discharges and blood pressure elevated by FK506 treatment. In addition, systemic administration of memantine, a clinically used NMDA receptor antagonist, effectively attenuated FK506 treatment-induced hypertension in conscious rats. CONCLUSIONS: Our findings reveal that normal calcineurin activity in the PVN constitutively restricts sympathetic vasomotor tone via suppressing NMDA receptor activity, which may be targeted for treating calcineurin inhibitor-induced hypertension.
Assuntos
Hipertensão , Receptores de N-Metil-D-Aspartato , Animais , Pressão Sanguínea , Calcineurina , Inibidores de Calcineurina/farmacologia , Hipotálamo/metabolismo , N-Metilaspartato/farmacologia , Núcleo Hipotalâmico Paraventricular , Ratos , Receptores de N-Metil-D-Aspartato/metabolismo , Sistema Nervoso Simpático , Tacrolimo/farmacologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologiaRESUMO
The pro-nociceptive role of glutamate in the CNS in migraine pathophysiology is well established. Glutamate, released from trigeminal afferents, activates second order nociceptive neurons in the brainstem. However, the function of peripheral glutamate receptors in the trigeminovascular system suggested as the origin site for migraine pain, is less known. In the current project, we used calcium imaging and patch clamp recordings from trigeminal ganglion (TG) neurons, immunolabelling, CGRP assay and direct electrophysiological recordings from rat meningeal afferents to investigate the role of glutamate in trigeminal nociception. Glutamate, aspartate, and, to a lesser extent, NMDA under free-magnesium conditions, evoked calcium transients in a fraction of isolated TG neurons, indicating functional expression of NMDA receptors. The fraction of NMDA sensitive neurons was increased by the migraine mediator CGRP. NMDA also activated slowly desensitizing currents in 37% of TG neurons. However, neither glutamate nor NMDA changed the level of extracellular CGRP. TG neurons expressed both GluN2A and GluN2B subunits of NMDA receptors. In addition, after removal of magnesium, NMDA activated persistent spiking activity in a fraction of trigeminal nerve fibers in meninges. Thus, glutamate activates NMDA receptors in somas of TG neurons and their meningeal nerve terminals in magnesium-dependent manner. These findings suggest that peripherally released glutamate can promote excitation of meningeal afferents implicated in generation of migraine pain in conditions of inherited or acquired reduced magnesium blockage of NMDA channels and support the usage of magnesium supplements in migraine.
Assuntos
Cálcio/metabolismo , Ácido Glutâmico/farmacologia , Nociceptividade/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Gânglio Trigeminal/citologia , Animais , Ácido Aspártico/farmacologia , Células Cultivadas , Masculino , Transtornos de Enxaqueca/metabolismo , N-Metilaspartato/farmacologia , Técnicas de Patch-Clamp , Ratos , Gânglio Trigeminal/efeitos dos fármacos , Gânglio Trigeminal/metabolismoRESUMO
OBJECTIVES: The effects of intra-ventral hippocampal memantine administration in male NMRI stressed mice were studied. METHODS: Two stainless steel gauge 23 guide cannulas were placed in the middle part of the mice ventral hippocampus using stereotaxic coordination. Seven days later, the animals were undergone to the stress protocol as follows: They experience four consecutive electro-foot shock stress sessions lasting for 10 min. Five or 30 min before each stress session, the animals received intra-ventral hippocampal (0.1, 1 and, 5 µg/mouse) or intraperitoneal (1, 5, and 10 mg/kg) memantine respectively. Eight days after stress termination, the animals were tested either for the maintenance of either anxiety (elevated plus maze) or depression (forced swimming test). RESULTS: Animals show anxiety eight days after stress termination. Intra-ventral hippocampal infusion of memantine (5 µg/mouse) 5 min before stress inhibited the anxiety-like behaviors. However, other doses of the drug exacerbate the stress effect. The drug, when injected peripherally exacerbated the stress effect in all doses. The drug by itself had no effect. In addition, animals also show depression nine days after stress termination and memantine (0.1, 1, and 5 µg/mouse) reduced the stress effect. The drug (0.1 µg/mouse) by itself induced depression in the animals. However, the drug when injected peripherally reduced the stress effect in all doses. CONCLUSIONS: It could be concluded that NMDA glutamate receptors in the ventral hippocampus may play a pivotal role in the mediation of maintenance of anxiety and depression induced by stress in the mice.
Assuntos
Ansiolíticos , Animais , Ansiolíticos/farmacologia , Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Comportamento Animal , Hipocampo , Masculino , Memantina/farmacologia , Memantina/uso terapêutico , Camundongos , N-Metilaspartato/farmacologia , Aço Inoxidável/farmacologiaRESUMO
We have recently demonstrated that bioactive molecules, extracted by high pressure and temperature from olive pomace, counteract calcium-induced cell damage to different cell lines. Here, our aim was to study the effect of the same extract on murine cortical neurons, since the preservation of the intracellular Ca2+-homeostasis is essential for neuronal function and survival. Accordingly, we treated neurons with different stimuli in order to evoke cytotoxic glutamatergic activation. In these conditions, the high-pressure and temperature extract from olive pomace (HPTOPE) only abolished the effects of N-methyl-d-aspartate (NMDA). Particularly, we observed that HPTOPE was able to promote the neuron rescue from NMDA-induced cell death. Moreover, we demonstrated that HPTOPE is endowed with the ability to maintain the intracellular Ca2+-homeostasis following NMDA receptor overactivation, protecting neurons from Ca2+-induced adverse effects, including aberrant calpain proteolytic activity. Moreover, we highlight the importance of the extraction conditions used that, without producing toxic molecules, allow us to obtain protecting molecules belonging to proanthocyanidin derivatives like procyanidin B2. In conclusion, we can hypothesize that HPTOPE, due to its functional and nontoxic properties on neuronal primary culture, can be utilized for future therapeutic interventions for neurodegeneration.
Assuntos
Biflavonoides/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Catequina/farmacologia , N-Metilaspartato/efeitos adversos , Neurônios/metabolismo , Olea/química , Extratos Vegetais/farmacologia , Proantocianidinas/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Biflavonoides/química , Catequina/química , Morte Celular/efeitos dos fármacos , Células Cultivadas , Camundongos , N-Metilaspartato/farmacologia , Neurônios/patologia , Extratos Vegetais/química , Proantocianidinas/químicaRESUMO
Purpose: To investigate the neuroprotective properties of creatine in the retina using in vitro and in vivo models of injury. Methods: Two different rat retinal culture systems (one containing retinal ganglion cells [RGC] and one not) were subjected to either metabolic stress, via treatments with the mitochondrial complex IV inhibitor sodium azide, or excitotoxic stress, via treatment with N-methyl-D-aspartate for 24 hours, in the presence or absence of creatine (0.5, 1.0, and 5.0 mM). Neuronal survival was assessed by immunolabeling for cell-specific antigens. Putative mechanisms of creatine action were investigated in vitro. Expression of creatine kinase (CK) isoenzymes in the rat retina was examined using Western blotting and immunohistochemistry. The effect of oral creatine supplementation (2%, wt/wt) on retinal and blood creatine levels was determined as well as RGC survival in rats treated with N-methyl-D-aspartate (NMDA; 10 nmol) or high IOP-induced ischemia reperfusion. Results: Creatine significantly prevented neuronal death induced by sodium azide and NMDA in both culture systems. Creatine administration did not alter cellular adenosine triphosphate (ATP). Inhibition of CK blocked the protective effect of creatine. Retinal neurons, including RGCs, expressed predominantly mitochondrial CK isoforms, while glial cells expressed exclusively cytoplasmic CKs. In vivo, NMDA and ischemia reperfusion caused substantial loss of RGCs. Creatine supplementation led to elevated blood and retinal levels of this compound but did not significantly augment RGC survival in either model. Conclusions: Creatine increased neuronal survival in retinal cultures; however, no significant protection of RGCs was evident in vivo, despite elevated levels of this compound being present in the retina after oral supplementation.
Assuntos
Creatina/farmacologia , Fármacos Neuroprotetores/farmacologia , Traumatismo por Reperfusão/prevenção & controle , Degeneração Retiniana/prevenção & controle , Células Ganglionares da Retina/efeitos dos fármacos , Animais , Western Blotting , Sobrevivência Celular/fisiologia , Células Cultivadas , Creatina Quinase/metabolismo , Eletrorretinografia , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Isoenzimas/metabolismo , N-Metilaspartato/farmacologia , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/metabolismo , Retina/enzimologia , Retina/fisiopatologia , Degeneração Retiniana/metabolismo , Células Ganglionares da Retina/metabolismo , Azida Sódica/farmacologia , Estresse FisiológicoRESUMO
Autosomal dominant mutations in GRIN2B are associated with severe encephalopathy, but little is known about the pathophysiological outcomes and any potential therapeutic interventions. Genetic studies have described the association between de novo mutations of genes encoding the subunits of the N-methyl-d-aspartate receptor (NMDAR) and severe neurological conditions. Here, we evaluated a missense mutation in GRIN2B, causing a proline-to-threonine switch (P553T) in the GluN2B subunit of NMDAR, which was found in a 5-year-old patient with Rett-like syndrome with severe encephalopathy. Structural molecular modeling predicted a reduced pore size of the mutant GluN2B-containing NMDARs. Electrophysiological recordings in a HEK-293T cell line expressing the mutated subunit confirmed this prediction and showed an associated reduced glutamate affinity. Moreover, GluN2B(P553T)-expressing primary murine hippocampal neurons showed decreased spine density, concomitant with reduced NMDA-evoked currents and impaired NMDAR-dependent insertion of the AMPA receptor subunit GluA1 at stimulated synapses. Furthermore, the naturally occurring coagonist d-serine restored function to GluN2B(P553T)-containing NMDARs. l-Serine dietary supplementation of the patient was hence initiated, resulting in the increased abundance of d-serine in the plasma and brain. The patient has shown notable improvements in motor and cognitive performance and communication after 11 and 17 months of l-serine dietary supplementation. Our data suggest that l-serine supplementation might ameliorate GRIN2B-related severe encephalopathy and other neurological conditions caused by glutamatergic signaling deficiency.
Assuntos
Encefalopatias , Suplementos Nutricionais , Mutação com Perda de Função , Receptores de N-Metil-D-Aspartato , Síndrome de Rett , Serina , Animais , Encefalopatias/tratamento farmacológico , Encefalopatias/genética , Encefalopatias/metabolismo , Encefalopatias/patologia , Criança , Cognição/efeitos dos fármacos , Humanos , Masculino , Camundongos , Modelos Moleculares , Atividade Motora/efeitos dos fármacos , Atividade Motora/genética , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Síndrome de Rett/tratamento farmacológico , Síndrome de Rett/genética , Síndrome de Rett/metabolismo , Síndrome de Rett/patologia , Serina/administração & dosagem , Serina/farmacocinéticaRESUMO
Noradrenergic projections from the nucleus tractus solitarius (NTS) to the hypothalamic paraventricular nucleus (PVN) are involved in nicotine (Nic) dependence. Nic induces hypothalamic norepinephrine (NE) release through N-methyl-d-aspartate receptors (NMDARs) and nitric oxide in the NTS. However, acupuncture attenuates Nic withdrawal-induced anxiety. Therefore, this study investigated the effects of acupuncture on Nic-induced hypothalamic NE release. Rats received an intravenous infusion of Nic (90 µg/kg, over 60 s) and extracellular NE levels in the PVN were determined by in vivo microdialysis. Immediately after Nic administration, the rats were bilaterally treated with acupuncture at acupoint HT7 (Shen-Men) or PC6 (Nei-Guan), or a non-acupoint (tail) for 60 s. Acupuncture at HT7, but not at PC6 or the tail, significantly reduced Nic-induced NE release. However, this was abolished by a post-acupuncture infusion of either NMDA or sodium nitroprusside into the NTS. Additionally, acupuncture at HT7, but not the control points, prevented Nic-induced plasma corticosterone secretion and inhibited Nic-induced increases in the phosphorylation of neuronal nitric oxide synthase (nNOS) and endothelial NOS in the NTS. These findings suggest that acupuncture at HT7 reduces Nic-induced NE release in the PVN via inhibition of the solitary NMDAR/NOS pathway.
Assuntos
Terapia por Acupuntura , Nicotina/farmacologia , Óxido Nítrico Sintase Tipo I/metabolismo , Norepinefrina/metabolismo , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Corticosterona/sangue , Infusões Intravenosas , Masculino , Microdiálise , N-Metilaspartato/administração & dosagem , N-Metilaspartato/farmacologia , Nicotina/administração & dosagem , Nicotina/antagonistas & inibidores , Óxido Nítrico Sintase Tipo III/metabolismo , Nitroprussiato/administração & dosagem , Nitroprussiato/farmacologia , Fosforilação/efeitos dos fármacos , RatosRESUMO
Bergenia ciliata (Haw) Sternb. possess immunomodulatory, anti-inflammatory, antioxidant, anti-urolithiatic, wound healing, anti-malarial, anti-diabetic and anti-cancer properties. Moreover, the methanolic extracts of the rhizomes of the plant were found to demonstrate beneficial neuroprotective effects in the intracerebroventricular streptozotocin-induced model in rats. Thus, the present study was undertaken to further explore the neuroprotective potential of the aqueous (BA) and methanolic extracts (BM) of B. ciliata through various in-vitro and in-vivo studies. Both the extracts at all tested concentrations i.e. 50-50,000 ng/mL did not cause any significant reduction of cell viability of SH-SY5Y cells when tested for 48 h when assessed through MTT and resazurin metabolism- based cell viability assays. The pre-treatment with the extracts could confer significant (p < 0.001) and dose-dependent protective effects against NMDA induced injury in SH-SY5Y cells. BM [IC50: 5.7 and 5.19 µg/mL for acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) respectively] led to more potent inhibition of both the enzymes as compared to BA (IC50: 227.12 and 23.25 µg/mL for AChE and BuChE respectively). BM also proved to be a 1.85-fold better scavenger of the DPPH free radicals as compared to BA. Thus, BM was taken further for the evaluation of the beneficial effects of 14-day pre-treatment in rats in the scopolamine (2 mg/kg, i.p.) induced amnesia model at 125, 250 and 500 mg/kg, p.o. BM pre-treatment at 250 and 500 mg/kg could significantly ameliorate the cognitive impairment (p < 0.001), inhibit AChE (p < 0.001) and BuChE (p < 0.05) activity, restore GSH levels (p < 0.05) in serum and brain homogenates and recover the morphology of hippocampal neurons back to normal. Moreover, the BM administration at 500 mg/kg also showed beneficial effects through the significant (p < 0.05) reduction of Aß1-42, phosphorylated tau (p-tau) and GSK-3ß immunoreactivity in the brain homogenates of the intracerebroventricularly streptozotocin (ICV STZ) injected rats as observed from the results of the ELISA assays. The outcomes of the study unveiled that BM exerts its beneficial effects through prevention of NMDA induced excitotoxic cell death, dual cholinesterase inhibition, antioxidant activity coupled with the reduction of the immunoreactivity for the Aß1-42, p-tau and GSK-3ß indicating its potential to be screened further for various other models to determine the exact mechanism of action.
Assuntos
Amnésia/tratamento farmacológico , Disfunção Cognitiva/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Extratos Vegetais/farmacologia , Acetilcolinesterase/metabolismo , Amnésia/induzido quimicamente , Amnésia/metabolismo , Animais , Antioxidantes/farmacologia , Encéfalo/efeitos dos fármacos , Butirilcolinesterase/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/metabolismo , Humanos , Masculino , N-Metilaspartato/farmacologia , Neurônios/efeitos dos fármacos , Ratos , Ratos Wistar , Escopolamina/farmacologia , Estreptozocina/farmacologiaRESUMO
Many naturalistic behaviors are built from modular components that are expressed sequentially. Although striatal circuits have been implicated in action selection and implementation, the neural mechanisms that compose behavior in unrestrained animals are not well understood. Here, we record bulk and cellular neural activity in the direct and indirect pathways of dorsolateral striatum (DLS) as mice spontaneously express action sequences. These experiments reveal that DLS neurons systematically encode information about the identity and ordering of sub-second 3D behavioral motifs; this encoding is facilitated by fast-timescale decorrelations between the direct and indirect pathways. Furthermore, lesioning the DLS prevents appropriate sequence assembly during exploratory or odor-evoked behaviors. By characterizing naturalistic behavior at neural timescales, these experiments identify a code for elemental 3D pose dynamics built from complementary pathway dynamics, support a role for DLS in constructing meaningful behavioral sequences, and suggest models for how actions are sculpted over time.
Assuntos
Comportamento Animal , Corpo Estriado/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Cálcio/metabolismo , Corpo Estriado/efeitos dos fármacos , Eletrodos Implantados , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , N-Metilaspartato/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Fotometria , Receptores de Dopamina D1/deficiência , Receptores de Dopamina D1/genéticaRESUMO
AIMS: Death-associated protein kinase 1 (DAPK1) is a kinase found to promote neuronal apoptosis induced by ischemia. Extracellular signal-regulated kinase (ERK) was identified as a key molecule in DAPK1 signaling. However, the mechanisms of neuronal ischemia reperfusion injury remain unknown. Here, we investigate the influence of DAPK1-ERK signal on neuronal apoptosis following ischemia reperfusion. METHODS: Mouse N2a cells were used in this study and primary cultured neurons along with mice were adopted as supplements. Oxygen glucose deprivation (OGD) or administration of N-methyl-d-aspartate (NMDA) and glycine was performed on cells while middle cerebral artery occlusion (MCAO) model on mice. DAPK1 knocking down was achieved by lentiviral-delivered shRNA. Protein expressions were evaluated by western blots. Protein-protein binding was confirmed by co-immunoprecipitation and immunofluorescent assay. Apoptosis of cells was measured by flow cytometry and lacate dehydrogenase (LDH) leakage assay. RESULTS: Ischemia reperfusion resulted in increased DAPK1 and ERK activation as well as aggravated apoptosis in a time-dependent manner. DAPK1 was proved to bind to ERK during reperfusion following OGD, MCAO and excitotoxicity model. Interception of this binding by knocking down DAPK1 led to nuclear translocation of ERK and reduced apoptosis. CONCLUSION: Our study revealed the DAPK1-ERK signal as a potential mechanism contributing to neuronal apoptosis in response to ischemia reperfusion. Disruption of this signal pathway could be a promising therapeutic target against stroke.
Assuntos
Apoptose/fisiologia , Proteínas Quinases Associadas com Morte Celular/metabolismo , Glucose/deficiência , Hipóxia/fisiopatologia , Sistema de Sinalização das MAP Quinases/fisiologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Córtex Cerebral/citologia , Citarabina/farmacologia , Proteínas Quinases Associadas com Morte Celular/genética , Modelos Animais de Doenças , Agonistas de Aminoácidos Excitatórios/farmacologia , Glicina/farmacologia , Imunossupressores/farmacologia , Infarto da Artéria Cerebral Média/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , N-Metilaspartato/farmacologia , Neuroblastoma/patologia , Neurônios/efeitos dos fármacos , Biossíntese de Proteínas/efeitos dos fármacos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismoRESUMO
The amygdala receives cortical inputs from the medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC) that are believed to affect emotional control and cue-outcome contingencies, respectively. Although mPFC impact on the amygdala has been studied, how the OFC modulates mPFC-amygdala information flow, specifically the infralimbic (IL) division of mPFC, is largely unknown. In this study, combined in vivo extracellular single-unit recordings and pharmacological manipulations were used in anesthetized rats to examine how OFC modulates amygdala neurons responsive to mPFC activation. Compared with basal condition, pharmacological (N-Methyl-D-aspartate) or electrical activation of the OFC exerted an inhibitory modulation of the mPFC-amygdala pathway, which was reversed with intra-amygdala blockade of GABAergic receptors with combined GABAA and GABAB antagonists (bicuculline and saclofen). Moreover, potentiation of the OFC-related pathways resulted in a loss of OFC control over the mPFC-amygdala pathway. These results show that the OFC potently inhibits mPFC drive of the amygdala in a GABA-dependent manner; but with extended OFC pathway activation this modulation is lost. Our results provide a circuit-level basis for this interaction at the level of the amygdala, which would be critical in understanding the normal and pathophysiological control of emotion and contingency associations regulating behavior.
Assuntos
Tonsila do Cerebelo/fisiologia , Lobo Frontal/fisiologia , Inibição Neural/fisiologia , Neurônios/fisiologia , Tonsila do Cerebelo/efeitos dos fármacos , Anestesia , Animais , Baclofeno/análogos & derivados , Baclofeno/farmacologia , Bicuculina/farmacologia , Estimulação Elétrica , Emoções/fisiologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Lobo Frontal/efeitos dos fármacos , Antagonistas GABAérgicos/farmacologia , Masculino , Microeletrodos , N-Metilaspartato/farmacologia , Inibição Neural/efeitos dos fármacos , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Neurônios/efeitos dos fármacos , Ratos Sprague-Dawley , Receptores de GABA/metabolismo , Ácido gama-Aminobutírico/metabolismoRESUMO
Tramadol is an analgesic agent that is mainly used to treat moderate to severe pain. There is evidence that tramadol may have antidepressant property. However, the mechanisms underlying the antidepressant effects of tramadol have not been elucidated yet. Considering that fact that N-methyl-d-aspartate (NMDA) receptor signaling may play an important role in the pathophysiology of depression, the aim of the present study was to investigate the role of NMDA receptor signaling in the possible antidepressant-like effects of tramadol in the mouse forced swimming test (mFST). We found that tramadol exerted antidepressant-like effects at high dose (40mg/kg, intraperitoneally [i.p.]) in the mFST. Co-administration of non-effective doses of NMDA receptor antagonists (ketamine [1mg/kg, i.p.], MK-801 [0.05mg/kg, i.p.], or magnesium sulfate [10mg/kg, i.p.]) with sub-effective dose of tramadol (20mg/kg, i.p.) exerted significant antidepressant-like effects in the mFST. The antidepressant-like effects of tramadol (40mg/kg) was also inhibited by pre-treatment with non-effective dose of the NMDA receptor agonist NMDA (75mg/kg, i.p.). Our data suggest a role for NMDA receptor signaling in the antidepressant-like effects of tramadol in the mFST.
Assuntos
Antidepressivos/farmacologia , Transtorno Depressivo/tratamento farmacológico , Receptores de N-Metil-D-Aspartato/metabolismo , Tramadol/farmacologia , Animais , Transtorno Depressivo/metabolismo , Modelos Animais de Doenças , Maleato de Dizocilpina/farmacologia , Relação Dose-Resposta a Droga , Fármacos Atuantes sobre Aminoácidos Excitatórios/farmacologia , Ketamina/farmacologia , Sulfato de Magnésio/farmacologia , Masculino , Camundongos , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/agonistas , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , NataçãoRESUMO
Neurotoxicity and the accumulation of extracellular amyloid-beta1-42 (Aß) peptides are associated with the development of Alzheimer's disease (AD) and correlate with neuronal activity and network dysfunctions, ultimately leading to cellular death. However, research on neurodegenerative diseases is hampered by the paucity of reliable readouts and experimental models to study such functional decline from an early onset and to test rescue strategies within networks at cellular resolution. To overcome this important obstacle, we demonstrate a simple yet powerful in vitro AD model based on a rat hippocampal cell culture system that exploits large-scale neuronal recordings from 4096-electrodes on CMOS-chips for electrophysiological quantifications. This model allows us to monitor network activity changes at the cellular level and to uniquely uncover the early activity-dependent deterioration induced by Aß-neurotoxicity. We also demonstrate the potential of this in vitro model to test a plausible hypothesis underlying the Aß-neurotoxicity and to assay potential therapeutic approaches. Specifically, by quantifying N-methyl D-aspartate (NMDA) concentration-dependent effects in comparison with low-concentration allogenic-Aß, we confirm the role of extrasynaptic-NMDA receptors activation that may contribute to Aß-neurotoxicity. Finally, we assess the potential rescue of neural stem cells (NSCs) and of two pharmacotherapies, memantine and saffron, for reversing Aß-neurotoxicity and rescuing network-wide firing.