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1.
PLoS One ; 15(7): e0223395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645024

RESUMO

Development of the cerebral cortex may be influenced by the composition of the maternal gut microbiota. To test this possibility, we administered probiotic Lactococcus lactis in drinking water to mouse dams from day 10.5 of gestation until pups reached postnatal day 1 (P1). Pups were assessed in a battery of behavioral tests starting at 10 weeks old. We found that females, but not males, exposed to probiotic during prenatal development spent more time in the center of the open field and displayed decreased freezing time in cue associated learning, compared to controls. Furthermore, we found that probiotic exposure changed the density of cortical neurons and increased the density of blood vessels in the cortical plate of P1 pups. Sex-specific differences were observed in the number of mitotic neural progenitor cells, which were increased in probiotic exposed female pups. In addition, we found that probiotic treatment in the latter half of pregnancy significantly increased plasma oxytocin levels in mouse dams, but not in the offspring. These results suggest that exposure of naïve, unstressed dams to probiotic may exert sex-specific long-term effects on cortical development and anxiety related behavior in the offspring.


Assuntos
Ansiedade/prevenção & controle , Córtex Cerebral/efeitos dos fármacos , Lactococcus lactis , Efeitos Tardios da Exposição Pré-Natal/psicologia , Probióticos/farmacologia , Animais , Animais Recém-Nascidos , Contagem de Células , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/citologia , Córtex Cerebral/crescimento & desenvolvimento , Medo , Feminino , Aprendizagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/citologia , Ocitocina/metabolismo , Gravidez , Caracteres Sexuais
2.
Mol Cell ; 79(3): 443-458.e7, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32649883

RESUMO

Despite the prominent role of TDP-43 in neurodegeneration, its physiological and pathological functions are not fully understood. Here, we report an unexpected role of TDP-43 in the formation of dynamic, reversible, liquid droplet-like nuclear bodies (NBs) in response to stress. Formation of NBs alleviates TDP-43-mediated cytotoxicity in mammalian cells and fly neurons. Super-resolution microscopy reveals distinct functions of the two RRMs in TDP-43 NB formation. TDP-43 NBs are partially colocalized with nuclear paraspeckles, whose scaffolding lncRNA NEAT1 is dramatically upregulated in stressed neurons. Moreover, increase of NEAT1 promotes TDP-43 liquid-liquid phase separation (LLPS) in vitro. Finally, we discover that the ALS-associated mutation D169G impairs the NEAT1-mediated TDP-43 LLPS and NB assembly, causing excessive cytoplasmic translocation of TDP-43 to form stress granules, which become phosphorylated TDP-43 cytoplasmic foci upon prolonged stress. Together, our findings suggest a stress-mitigating role and mechanism of TDP-43 NBs, whose dysfunction may be involved in ALS pathogenesis.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteínas de Ligação a DNA/genética , Corpos de Inclusão Intranuclear/metabolismo , Neurônios/metabolismo , RNA Longo não Codificante/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Animais Geneticamente Modificados , Arsenitos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/ultraestrutura , Grânulos Citoplasmáticos/efeitos dos fármacos , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/ultraestrutura , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Drosophila melanogaster , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Corpos de Inclusão Intranuclear/efeitos dos fármacos , Corpos de Inclusão Intranuclear/ultraestrutura , Camundongos , Mutação , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Cultura Primária de Células , Transporte Proteico/efeitos dos fármacos , RNA Longo não Codificante/metabolismo , Transdução de Sinais , Estresse Fisiológico
3.
PLoS Biol ; 18(6): e3000744, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32559190

RESUMO

Dopamine guides behavior and learning through pleasure, according to classic understanding. Dopaminergic neurons are traditionally thought to signal positive or negative prediction errors (PEs) when reward expectations are, respectively, exceeded or not matched. These signed PEs are quite different from the unsigned PEs, which report surprise during sensory processing. But mounting theoretical accounts from the predictive processing framework postulate that dopamine, as a neuromodulator, could potentially regulate the postsynaptic gain of sensory neurons, thereby scaling unsigned PEs according to their expected precision or confidence. Despite ample modeling work, the physiological effects of dopamine on the processing of surprising sensory information are yet to be addressed experimentally. In this study, we tested how dopamine modulates midbrain processing of unexpected tones. We recorded extracellular responses from the rat inferior colliculus to oddball and cascade sequences, before, during, and after the microiontophoretic application of dopamine or eticlopride (a D2-like receptor antagonist). Results demonstrate that dopamine reduces the net neuronal responsiveness exclusively to unexpected sensory input without significantly altering the processing of expected input. We conclude that dopaminergic projections from the thalamic subparafascicular nucleus to the inferior colliculus could encode the expected precision of unsigned PEs, attenuating via D2-like receptors the postsynaptic gain of sensory inputs forwarded by the auditory midbrain neurons. This direct dopaminergic modulation of sensory PE signaling has profound implications for both the predictive coding framework and the understanding of dopamine function.


Assuntos
Córtex Cerebral/fisiologia , Dopamina/farmacologia , Som , Estimulação Acústica , Adaptação Fisiológica , Animais , Córtex Cerebral/efeitos dos fármacos , Feminino , Ratos Long-Evans , Salicilamidas/farmacologia , Tálamo/fisiologia
4.
Toxicology ; 440: 152500, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32428529

RESUMO

Autism spectrum disorders (ASD) include neurodevelopmental disorders in which behavioral deficits can result from neuronal imbalance of excitation to inhibition (E/I) in the brain. Here we used RT-qPCR to screen for the expression of 99 genes associated with excitatory (glutamatergic) and inhibitory (GABAergic) neurotransmission in the cerebral cortex, hippocampus and cerebellum of rats in an established VPA model of ASD. The largest changes in the expression of glutamatergic genes were found in the cerebral cortex, where 12 genes including these encoding some of the subunits of the ionotropic glutamate receptors, were upregulated, while 2 genes were downregulated. The expression of genes encoding the presynaptic glutamatergic proteins vGluT1 and mGluR7 and PKA, involved in downstream glutamatergic signaling, was elevated more than 100-fold. Changes in GABAergic gene expression were found in the cortex, cerebellum and hippocampus; 3 genes were upregulated, and 3 were downregulated. In conclusion, these results revealed that, in the ASD model, several glutamatergic genes in the rat cerebral cortex were upregulated, which contrasts with small and balanced changes in the expression of GABAergic genes. The VPA rat model, useful in studying the molecular basis of ASD, may be suitable for testing experimental therapies in these disabilities.


Assuntos
Transtorno Autístico/induzido quimicamente , Transtorno Autístico/genética , Ácido Glutâmico/genética , Ácido Valproico , Ácido gama-Aminobutírico/genética , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Feminino , GABAérgicos , Perfilação da Expressão Gênica , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ratos , Ratos Wistar , Receptores de Glutamato Metabotrópico/biossíntese , Receptores de Glutamato Metabotrópico/genética , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Proteína Vesicular 1 de Transporte de Glutamato/biossíntese , Proteína Vesicular 1 de Transporte de Glutamato/genética
5.
Proc Natl Acad Sci U S A ; 117(20): 11118-11125, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32358198

RESUMO

Cortical network functioning critically depends on finely tuned interactions to afford neuronal activity propagation over long distances while avoiding runaway excitation. This importance is highlighted by the pathological consequences and impaired performance resulting from aberrant network excitability in psychiatric and neurological diseases, such as epilepsy. Theory and experiment suggest that the control of activity propagation by network interactions can be adequately described by a branching process. This hypothesis is partially supported by strong evidence for balanced spatiotemporal dynamics observed in the cerebral cortex; however, evidence of a causal relationship between network interactions and cortex activity, as predicted by a branching process, is missing in humans. Here this cause-effect relationship is tested by monitoring cortex activity under systematic pharmacological reduction of cortical network interactions with antiepileptic drugs. This study reports that cortical activity cascades, presented by the propagating patterns of epileptic spikes, as well as temporal correlations decline precisely as predicted for a branching process. The results provide a missing link to the branching process theory of cortical network function with implications for understanding the foundations of cortical excitability and its monitoring in conditions like epilepsy.


Assuntos
Anticonvulsivantes/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/metabolismo , Eletrocorticografia , Epilepsia , Humanos , Redes Neurais de Computação , Neurônios/fisiologia
6.
Biomed Khim ; 66(2): 130-137, 2020 Feb.
Artigo em Russo | MEDLINE | ID: mdl-32420893

RESUMO

Protein kinase CK2 is an important enzyme in the nervous system. The nuclear forms of CK2 regulate chromatin structure and gene expression, the key processes for long-term memory formation. Memory modulators, the Structural Analogues of Etimizole (SAE), were able to increase or decrease the activity of chromatin-associated CK in the cortex and hippocampus of rat brain in vitro. In vivo memory enhancers from SAE-group (3 mg/kg) stimulated CK2 activity and the transcriptional ability of chromatin in the cortex and hippocampus, starting from 30 min with a peak for 60 min and a duration up to 180 min. At these periods the memory inhibitor from the SAE-group reduced CK2 activity and chromatin transcription. It is assumed that the modulating effect of SAE on CK2 activity and transcription underlies the effects of these compounds on long-term memory.


Assuntos
Caseína Quinase II/metabolismo , Córtex Cerebral/efeitos dos fármacos , Cromatina , Etimizol/análogos & derivados , Etimizol/farmacologia , Hipocampo/efeitos dos fármacos , Animais , Fosforilação , Ratos , Transcrição Genética
7.
PLoS One ; 15(5): e0232233, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365077

RESUMO

The physiological actions of orally ingested peptides on the brain remain poorly understood. This study examined the effects of 39 orally administered synthetic Tyr-containing dipeptides on the enhancement of brain norepinephrine metabolism in mice by comparing the concentration of 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG). Although Tyr-Tyr administration increased blood and cerebral cortex (Cx) Tyr concentrations the most, Tyr-Trp increased Cx MHPG concentration the most. The oral administration of Tyr-Trp ameliorated a short-term memory deficit of a mouse model of cognitive dysfunction induced by amyloid beta peptide 25-35. Gene expression profiling of mouse brain using a microarray indicated that Tyr-Trp administration led to a wide variety of changes in mRNA levels, including the upregulation of genes encoding molecules involved in catecholamine metabolism. A comparative metabolome analysis of the Cx of mice given Tyr-Trp or Tyr-Tyr demonstrated that Tyr-Trp administration yielded higher concentrations of Trp and kynurenine pathway metabolites than Tyr-Tyr administration, as well as higher L-dopa levels, which is the initial product of catecholamine metabolism. Catecholamines were not significantly increased in the Cx of the Tyr-Tyr group compared with the Tyr-Trp group, despite a marked increase in Tyr. Presumably, Tyr-Trp administration enhances catecholamine synthesis and metabolism via the upregulation of genes involved in Tyr and Trp metabolism as well as metabolites of Tyr and Trp. These findings strongly suggest that orally ingested Tyr-Trp modulates the brain metabolome involved in catecholamine metabolism and contributes to higher brain function.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Dipeptídeos/administração & dosagem , Memória de Curto Prazo/efeitos dos fármacos , Metoxi-Hidroxifenilglicol/análise , Administração Oral , Doença de Alzheimer/induzido quimicamente , Doença de Alzheimer/genética , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/efeitos adversos , Animais , Catecolaminas/biossíntese , Córtex Cerebral/química , Córtex Cerebral/efeitos dos fármacos , Dipeptídeos/farmacologia , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Humanos , Masculino , Metaboloma/efeitos dos fármacos , Camundongos , Fragmentos de Peptídeos/efeitos adversos
8.
J Vasc Res ; 57(4): 178-184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32434183

RESUMO

BACKGROUND: Lysophosphatidic acid (LPA) is a small phospholipid-signaling molecule, which can alter responses to stress in the central nervous system. OBJECTIVE: We hypothesized that exogenous LPA would increase the size of infarct and reduce microregional O2 supply/consumption balance after cerebral ischemia-reperfusion. METHODS: This was tested in isoflurane-anesthetized rats with middle cerebral artery blockade for 1 h and reperfusion for 2 h with or without LPA (1 mg/kg, at 30, 60, and 90 min after reperfusion). Regional cerebral blood flow was determined using a C14-iodoantipyrine autoradiographic technique. Regional small-vessel (20-60 µm in diameter) arterial and venous oxygen saturations were determined microspectrophotometrically. RESULTS: There were no significant hemodynamic or arterial blood gas differences between groups. The control ischemic-reperfused cortex had a similar O2 consumption to the contralateral cortex. However, microregional O2 supply/consumption balance was significantly reduced in the ischemic-reperfused cortex with many areas of low O2 saturation (43 of 80 veins with O2 saturation below 50%). LPA did not significantly alter cerebral blood flow, but it did significantly increase O2 extraction and consumption of the ischemic-reperfused region. It also significantly increased the number of small veins with low O2 saturations in the reperfused region (76 of 80 veins with O2 saturation below 50%). This was associated with a significantly increased cortical infarct size after LPA administration (11.4 ± 0.5% control vs. 16.4 ± 0.6% LPA). CONCLUSION: This suggests that LPA reduces cell survival and that it is associated with an increase in the number of small microregions with reduced local oxygen balance after cerebral ischemia-reperfusion.


Assuntos
Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/efeitos dos fármacos , Circulação Cerebrovascular/efeitos dos fármacos , Infarto da Artéria Cerebral Média/patologia , Lisofosfolipídeos/toxicidade , Microcirculação/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Oxigênio/sangue , Traumatismo por Reperfusão/patologia , Animais , Morte Celular/efeitos dos fármacos , Córtex Cerebral/patologia , Veias Cerebrais/efeitos dos fármacos , Veias Cerebrais/patologia , Veias Cerebrais/fisiopatologia , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/sangue , Infarto da Artéria Cerebral Média/fisiopatologia , Masculino , Ratos Endogâmicos F344 , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/fisiopatologia
9.
Toxicology ; 438: 152442, 2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32278051

RESUMO

Bisphenol A (BPA) is a well-known endocrine disruptor used to manufacture polycarbonate plastics and epoxy resins. BPA exposure especially occupational perinatal exposure to has been linked to numerous adverse effects for the offspring. Available data have shown that perinatal exposure to BPA contributes to neurodegenerative pathological changes; however, the potential mechanisms remain unclear. This study attempted to investigate the long-term consequences of perinatal exposure to BPA on the offspring mouse brain. The pregnant mice were given either a vehicle control or BPA (2, 10, 100 µg/kg/d) from day 6 of gestation until weaning (P6-PND21, foetal and neonatal exposure). At 3, 6 and 9 months of age, the neurotoxic effects in the offspring in each group were investigated. We found that the spine density but not the dendritic branches in the hippocampus were noticeably reduced at 6 and 9 months of age. Meanwhile, p-Tau, the characteristic protein for tauopathy, was dramatically increased in both the hippocampus and cortex at 3-9 months of age. Mechanically, the balance of kinase and protein phosphatase, which plays critical roles in p-Tau regulation, was disturbed. It indicated that GSK3ß and CDK5, two critical kinases, were activated in most of the BPA perinatal exposure group, while protein phosphatase 2A (PP2A), one of the important phosphatases, regulated p-Tau expression through its demethylation, methylation and phosphorylation. Taken together, the present study may be translatable to the human occupational BPA exposure due to a similar exposure level. BPA perinatal exposure causes long-term adverse effects on the mouse brain and may be a risk factor for tauopathies, and the CDK5/GSK3ß/PP2A axis might be a promising therapeutic target for BPA-induced neurodegenerative pathological changes.


Assuntos
Compostos Benzidrílicos/toxicidade , Córtex Cerebral/efeitos dos fármacos , Quinase 5 Dependente de Ciclina/metabolismo , Disruptores Endócrinos/toxicidade , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/efeitos dos fármacos , Síndromes Neurotóxicas/etiologia , Fenóis/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Proteína Fosfatase 2/metabolismo , Proteínas tau/metabolismo , Animais , Córtex Cerebral/enzimologia , Córtex Cerebral/patologia , Espinhas Dendríticas/efeitos dos fármacos , Espinhas Dendríticas/enzimologia , Espinhas Dendríticas/patologia , Feminino , Idade Gestacional , Hipocampo/enzimologia , Hipocampo/patologia , Masculino , Exposição Materna , Camundongos Endogâmicos C57BL , Síndromes Neurotóxicas/enzimologia , Síndromes Neurotóxicas/patologia , Fosforilação , Gravidez
10.
PLoS One ; 15(4): e0231721, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32294144

RESUMO

Opioid addiction is recognized as a chronic relapsing brain disease resulting from repeated exposure to opioid drugs. Cellular and molecular mechanisms underlying the ability of organism to return back to the physiological norm after cessation of drug supply are not fully understood. The aim of this work was to extend our previous studies of morphine-induced alteration of rat forebrain cortex protein composition to the hippocampus. Rats were exposed to morphine for 10 days and sacrificed 24 h (groups +M10 and -M10) or 20 days after the last dose of morphine (groups +M10/-M20 and -M10/-M20). The six altered proteins (≥2-fold) were identified in group (+M10) when compared with group (-M10) by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). The number of differentially expressed proteins was increased to thirteen after 20 days of the drug withdrawal. Noticeably, the altered level of α-synuclein, ß-synuclein, α-enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was also determined in both (±M10) and (±M10/-M20) samples of hippocampus. Immunoblot analysis of 2D gels by specific antibodies oriented against α/ß-synucleins and GAPDH confirmed the data obtained by 2D-DIGE analysis. Label-free quantification identified nineteen differentially expressed proteins in group (+M10) when compared with group (-M10). After 20 days of morphine withdrawal (±M10/-M20), the number of altered proteins was increased to twenty. We conclude that the morphine-induced alteration of protein composition in rat hippocampus after cessation of drug supply proceeds in a different manner when compared with the forebrain cortex. In forebrain cortex, the total number of altered proteins was decreased after 20 days without morphine, whilst in hippocampus, it was increased.


Assuntos
Analgésicos Opioides/efeitos adversos , Hipocampo/efeitos dos fármacos , Morfina/efeitos adversos , Transtornos Relacionados ao Uso de Opioides/patologia , Síndrome de Abstinência a Substâncias/patologia , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/patologia , Humanos , Masculino , Proteômica , Ratos , Ratos Wistar , Fatores de Tempo
11.
J Neurosci ; 40(21): 4251-4263, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32332118

RESUMO

Soluble amyloid ß (Aß)-induced synaptic dysfunction is an early event in the pathogenesis of Alzheimer's disease (AD) that precedes the deposition of insoluble Aß and correlates with the development of cognitive deficits better than the number of plaques. The mammalian plasminogen activation (PA) system catalyzes the generation of plasmin via two activators: tissue-type (tPA) and urokinase-type (uPA). A dysfunctional tPA-plasmin system causes defective proteolytic degradation of Aß plaques in advanced stages of AD. In contrast, it is unknown whether uPA and its receptor (uPAR) contribute to the pathogenesis of this disease. Neuronal cadherin (NCAD) plays a pivotal role in the formation of synapses and dendritic branches, and Aß decreases its expression in cerebral cortical neurons. Here we show that neuronal uPA protects the synapse from the harmful effects of soluble Aß. However, Aß-induced inactivation of the eukaryotic initiation factor 2α halts the transcription of uPA mRNA, leaving unopposed the deleterious effects of Aß on the synapse. In line with these observations, the synaptic abundance of uPA, but not uPAR, is decreased in the frontal cortex of AD patients and 5xFAD mice, and in cerebral cortical neurons incubated with soluble Aß. We found that uPA treatment increases the synaptic expression of NCAD by a uPAR-mediated plasmin-independent mechanism, and that uPA-induced formation of NCAD dimers protects the synapse from the harmful effects of soluble Aß oligomers. These data indicate that Aß-induced decrease in the synaptic abundance of uPA contributes to the development of synaptic damage in the early stages of AD.SIGNIFICANCE STATEMENT Soluble amyloid ß (Aß)-induced synaptic dysfunction is an early event in the pathogenesis of cognitive deficits in Alzheimer's disease (AD). We found that neuronal urokinase-type (uPA) protects the synapse from the deleterious effects of soluble Aß. However, Aß-induced inactivation of the eukaryotic initiation factor 2α decreases the synaptic abundance of uPA, leaving unopposed the harmful effects of Aß on the synapse. In line with these observations, the synaptic expression of uPA is decreased in the frontal cortex of AD brains and 5xFAD mice, and uPA treatment abrogates the deleterious effects of Aß on the synapse. These results unveil a novel mechanism of Aß-induced synaptic dysfunction in AD patients, and indicate that recombinant uPA is a potential therapeutic strategy to protect the synapse before the development of irreversible brain damage.


Assuntos
Peptídeos beta-Amiloides/farmacologia , Córtex Cerebral/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Ativador de Plasminogênio Tipo Uroquinase/genética , Ativador de Plasminogênio Tipo Uroquinase/farmacologia , Animais , Células Cultivadas , Córtex Cerebral/metabolismo , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/metabolismo
12.
Br J Anaesth ; 124(5): 594-602, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32171548

RESUMO

BACKGROUND: Exposure to surgery with general anaesthesia (surgery/GA) is associated with cortical atrophy, but the aetiology remains unknown. Amyloid-ß (Aß) deposition is one of the hallmark pathological characteristics of Alzheimer's disease (AD). We examined brain Aß burden in study participants exposed to surgery/GA. METHODS: We performed a cross-sectional analysis of residents of Olmsted County, MN, USA, in the Mayo Clinic Study of Aging who were aged 70-97 yr and underwent measurement of (i) brain Aß with Pittsburgh compound B positron emission tomography (PiB PET), (ii) brain glucose metabolism with 18-fluorodeoxyglucose (FDG) PET, and (iii) temporal cortical thickness with MRI. Separate analyses were performed with exposure to surgery/GA, defined as occurring after age 40 yr, and with exposure to surgery/GA, defined as occurring within 20 yr before neuroimaging. Imaging measurements were compared between participants who were exposed to surgery/GA vs not exposed. RESULTS: Of the 2563 participants, 585 had PET scans. Regardless of the definition used to quantify exposure, no significant associations were detected between exposure and either global PiB PET or FDG PET. In contrast, exposure to surgery/GA was associated with an increased likelihood of abnormal cortical thinning: odds ratio (OR)=1.98 (95% confidence interval [CI]: 1.19-3.31); P=0.010 in those exposed after age 40 yr, and OR=1.64 (95% CI: 1.05-2.55); P=0.029 in those exposed in the prior 20 yr. CONCLUSIONS: Exposure to surgery/GA is not associated with increases in cortical amyloid deposition. This finding suggests that the modest cortical thinning associated with surgery/GA is not related to AD pathology, but rather is caused by other processes.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Anestesia Geral/efeitos adversos , Encéfalo/metabolismo , Procedimentos Cirúrgicos Operatórios/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/efeitos dos fármacos , Envelhecimento/metabolismo , Anestésicos Gerais/farmacologia , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Estudos Transversais , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Tomografia por Emissão de Pósitrons/métodos , Período Pós-Operatório , Estudos Retrospectivos
13.
Cell ; 180(4): 666-676.e13, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-32084339

RESUMO

The mystery of general anesthesia is that it specifically suppresses consciousness by disrupting feedback signaling in the brain, even when feedforward signaling and basic neuronal function are left relatively unchanged. The mechanism for such selectiveness is unknown. Here we show that three different anesthetics have the same disruptive influence on signaling along apical dendrites in cortical layer 5 pyramidal neurons in mice. We found that optogenetic depolarization of the distal apical dendrites caused robust spiking at the cell body under awake conditions that was blocked by anesthesia. Moreover, we found that blocking metabotropic glutamate and cholinergic receptors had the same effect on apical dendrite decoupling as anesthesia or inactivation of the higher-order thalamus. If feedback signaling occurs predominantly through apical dendrites, the cellular mechanism we found would explain not only how anesthesia selectively blocks this signaling but also why conscious perception depends on both cortico-cortical and thalamo-cortical connectivity.


Assuntos
Anestésicos Gerais/farmacologia , Córtex Cerebral/efeitos dos fármacos , Células Piramidais/efeitos dos fármacos , Animais , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Antagonistas Colinérgicos/farmacologia , Estado de Consciência , Dendritos/efeitos dos fármacos , Dendritos/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Retroalimentação Fisiológica , Feminino , Masculino , Camundongos , Células Piramidais/fisiologia , Transmissão Sináptica , Tálamo/citologia , Tálamo/efeitos dos fármacos , Tálamo/fisiologia
14.
Neuron ; 106(1): 66-75.e12, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32053769

RESUMO

Functional MRI and electrophysiology studies suggest that consciousness depends on large-scale thalamocortical and corticocortical interactions. However, it is unclear how neurons in different cortical layers and circuits contribute. We simultaneously recorded from central lateral thalamus (CL) and across layers of the frontoparietal cortex in awake, sleeping, and anesthetized macaques. We found that neurons in thalamus and deep cortical layers are most sensitive to changes in consciousness level, consistent across different anesthetic agents and sleep. Deep-layer activity is sustained by interactions with CL. Consciousness also depends on deep-layer neurons providing feedback to superficial layers (not to deep layers), suggesting that long-range feedback and intracolumnar signaling are important. To show causality, we stimulated CL in anesthetized macaques and effectively restored arousal and wake-like neural processing. This effect was location and frequency specific. Our findings suggest layer-specific thalamocortical correlates of consciousness and inform how targeted deep brain stimulation can alleviate disorders of consciousness.


Assuntos
Estado de Consciência/fisiologia , Lobo Frontal/fisiologia , Núcleos Intralaminares do Tálamo/fisiologia , Lobo Parietal/fisiologia , Sono/fisiologia , Vigília/fisiologia , Anestesia Geral , Anestésicos Inalatórios/farmacologia , Anestésicos Intravenosos/farmacologia , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiologia , Estado de Consciência/efeitos dos fármacos , Estimulação Elétrica , Eletroencefalografia , Retroalimentação , Lobo Frontal/efeitos dos fármacos , Núcleos Intralaminares do Tálamo/efeitos dos fármacos , Isoflurano/farmacologia , Macaca , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiologia , Lobo Parietal/efeitos dos fármacos , Propofol/farmacologia
15.
Environ Toxicol ; 35(6): 683-696, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32061141

RESUMO

Methylmercury (MeHg) is a potent neurotoxin,which leads to a wide range of intracellular effects. The molecular mechanismsassociated to MeHg-induced neurotoxicity have not been fully understood.Oxidative stress, as well as synaptic glutamate (Glu) dyshomeostasis have beenidentified as two critical mechanisms during MeHg-mediated cytotoxicity. Here,we developed a rat model of MeHg poisoning to evaluate its neurotoxic effectsby focusing on cellular oxidative stress and synaptic Glu disruption. Inaddition, we investigated the neuroprotective role of alpha-lipoic acid (α-LA), a natural antioxidant, todeeply explore the underlying interaction between them. Fifty-six rats wererandomly divided into four groups: saline control, MeHg treatment (4 or 12µmol/kg MeHg), and α-LApre-treatment (35 µmol/kg α-LA+12µmol/kg MeHg). Rats exposed to 12 µmol/kg MeHg induced neuronal oxidativestress, with ROS accumulation and cellular antioxidant system impairment. Nrf2 andxCT pathways were activated with MeHg treatment. The enzymatic or non-enzymaticof cellular GSH synthesis were also disrupted by MeHg. On the other hand, the abnormalactivities of GS and PAG disturbed the "Glu-Gln cycle", leading to NMDARsover-activation, Ca2+ overload, and the calpain activation, which acceleratedNMDARs degradation. Meanwhile, the high expressions of phospho-p44/42 MAPK,phospho-p38 MAPK, phospho-CREB, and the high levels of caspase 3 and Bax/Bcl-2 finallyindicated the neuronal apoptosis after MeHg exposure. Pre-treatment with α-LA significantly preventedMeHg-induced neurotoxicity. In conclusion, the oxidative stress and synapticGlu dyshomeostasis contributed to MeHg-induced neuronal apoptosis. Alpha-LAattenuated these toxic effects through mechanisms of anti-oxidation andindirect Glu dyshomeostasis prevention.


Assuntos
Apoptose/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Compostos de Metilmercúrio/toxicidade , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Antioxidantes/metabolismo , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Masculino , Neurônios/metabolismo , Neurônios/patologia , Síndromes Neurotóxicas/metabolismo , Síndromes Neurotóxicas/patologia , Oxirredução , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Ácido Tióctico/farmacologia
16.
Toxicology ; 435: 152408, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32057834

RESUMO

PURPOSE: To investigate the effects and mechanisms of NADPH on Kainic acid (KA)-induced excitotoxicity. METHODS: KA, a non-N-methyl-d-aspartate glutamate receptor agonist, was exposed to adult SD rats via intrastriatal injection and rat primary cortical neurons to establish excitotoxic models in vivo and in vitro, respectively. To determine the effects of NADPH on KA-induced excitotoxicity, neuronal survival, neurologically behavioral score and oxidative stress were evaluated. To explore the mechanisms of neuroprotective effects of NADPH, the autophagy-lysosome pathway related proteins were detected. RESULTS: In vivo, NADPH (1 mg/kg or 2 mg/kg) diminished KA (2.5 nmol)-induced enlargement of lesion size in striatum, improved KA-induced dyskinesia and reversed KA-induced activation of glial cells. Nevertheless, the neuroprotective effect of NADPH was not significant under the condition of autophagy activation. NADPH (2 mg/kg) inhibited KA (2.5 nmol)-induced down-regulation of TP-53 induced glycolysis and apoptosis regulator (TIGAR) and p62, and up-regulation of the protein levels of LC3-II/LC3-I, Beclin-1 and Atg5. In vitro, the excitotoxic neuronal injury was induced after KA (50 µM, 100 µM or 200 µM) treatment as demonstrated by decreased cell viability. Moreover, KA (100 µM) increased the intracellular levels of calcium and reactive oxygen species (ROS) and declined the levels of the reduced form of glutathione (GSH). Pretreatment of NADPH (10 µM) effectively reversed these changes. Meanwhile NADPH (10 µM) inhibited KA (100 µM)-induced down-regulation of TIGAR and p62, and up-regulation of the ratio of LC3-II/LC3-I, Beclin-1, Atg5, active-cathepsin B and active-cathepsin D. CONCLUSIONS: Our data provide a possible mechanism that NADPH ameliorates KA-induced excitotoxicity by blocking the autophagy-lysosome pathway and up-regulating TIGAR along with its antioxidant properties.


Assuntos
Autofagia/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Corpo Estriado/efeitos dos fármacos , Agonistas de Aminoácidos Excitatórios/toxicidade , Ácido Caínico/toxicidade , Lisossomos/efeitos dos fármacos , NADP/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 5 Relacionada à Autofagia/metabolismo , Proteína Beclina-1/metabolismo , Comportamento Animal/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Lisossomos/metabolismo , Lisossomos/patologia , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Atividade Motora/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Monoéster Fosfórico Hidrolases/metabolismo , Ratos Sprague-Dawley , Proteína Sequestossoma-1/metabolismo
17.
Medicine (Baltimore) ; 99(5): e18441, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32000357

RESUMO

Various methods of assessing the depth of anesthesia (DoA) and reducing intraoperative awareness during general anesthesia have been extensively studied in anesthesiology. However, most of the DoA monitors do not include brain activity signal modeling. Here, we propose a new algorithm termed the cortical activity index (CAI) based on the brain activity signals. In this study, we enrolled 32 patients who underwent laparoscopic cholecystectomy. Raw electroencephalography (EEG) signals were acquired at a sampling rate of 128 Hz using BIS-VISTA with standard bispectral index (BIS) sensors. All data were stored on a computer for further analysis. The similarities and difference among spectral entropy, the BIS, and CAI were analyzed. Pearson correlation coefficient between the BIS and CAI was 0.825. The result of fitting the semiparametric regression models is the method CAI estimate (-0.00995; P = .0341). It is the estimated difference in the mean of the dependent variable between method BIS and CAI. The CAI algorithm, a simple and intuitive algorithm based on brain activity signal modeling, suggests an intrinsic relationship between the DoA and the EEG waveform. We suggest that the CAI algorithm might be used to quantify the DoA.


Assuntos
Algoritmos , Anestesia , Anestésicos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Eletroencefalografia , Adulto , Colecistectomia Laparoscópica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
Nat Commun ; 11(1): 640, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005806

RESUMO

Reduced food intake is common to many pathological conditions, such as infection and toxin exposure. However, cortical circuits that mediate feeding responses to these threats are less investigated. The anterior insular cortex (aIC) is a core region that integrates interoceptive states and emotional awareness and consequently guides behavioral responses. Here, we demonstrate that the right-side aIC CamKII+ (aICCamKII) neurons in mice are activated by aversive visceral signals. Hyperactivation of the right-side aICCamKII neurons attenuates food consumption, while inhibition of these neurons increases feeding and reverses aversive stimuli-induced anorexia and weight loss. Similar manipulation at the left-side aIC does not cause significant behavioral changes. Furthermore, virus tracing reveals that aICCamKII neurons project directly to the vGluT2+ neurons in the lateral hypothalamus (LH), and the right-side aICCamKII-to-LH pathway mediates feeding suppression. Our studies uncover a circuit from the cortex to the hypothalamus that senses aversive visceral signals and controls feeding behavior.


Assuntos
Agentes Aversivos/toxicidade , Córtex Cerebral/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Córtex Cerebral/efeitos dos fármacos , Feminino , Região Hipotalâmica Lateral/metabolismo , Hipotálamo/citologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vias Neurais/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo
19.
Anesthesiology ; 132(5): 1017-1033, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32032094

RESUMO

BACKGROUND: Investigations of the electrophysiology of gaseous anesthetics xenon and nitrous oxide are limited revealing inconsistent frequency-dependent alterations in spectral power and functional connectivity. Here, the authors describe the effects of sedative, equivalent, stepwise levels of xenon and nitrous oxide administration on oscillatory source power using a crossover design to investigate shared and disparate mechanisms of gaseous xenon and nitrous oxide anesthesia. METHODS: Twenty-one healthy males underwent simultaneous magnetoencephalography and electroencephalography recordings. In separate sessions, sedative, equivalent subanesthetic doses of gaseous anesthetic agents nitrous oxide and xenon (0.25, 0.50, and 0.75 equivalent minimum alveolar concentration-awake [MACawake]) and 1.30 MACawake xenon (for loss of responsiveness) were administered. Source power in various frequency bands were computed and statistically assessed relative to a conscious/pre-gas baseline. RESULTS: Observed changes in spectral-band power (P < 0.005) were found to depend not only on the gas delivered, but also on the recording modality. While xenon was found to increase low-frequency band power only at loss of responsiveness in both source-reconstructed magnetoencephalographic (delta, 208.3%, 95% CI [135.7, 281.0%]; theta, 107.4%, 95% CI [63.5, 151.4%]) and electroencephalographic recordings (delta, 260.3%, 95% CI [225.7, 294.9%]; theta, 116.3%, 95% CI [72.6, 160.0%]), nitrous oxide only produced significant magnetoencephalographic high-frequency band increases (low gamma, 46.3%, 95% CI [34.6, 57.9%]; high gamma, 45.7%, 95% CI [34.5, 56.8%]). Nitrous oxide-not xenon-produced consistent topologic (frontal) magnetoencephalographic reductions in alpha power at 0.75 MACawake doses (44.4%; 95% CI [-50.1, -38.6%]), whereas electroencephalographically nitrous oxide produced maximal reductions in alpha power at submaximal levels (0.50 MACawake, -44.0%; 95% CI [-48.1,-40.0%]). CONCLUSIONS: Electromagnetic source-level imaging revealed widespread power changes in xenon and nitrous oxide anesthesia, but failed to reveal clear universal features of action for these two gaseous anesthetics. Magnetoencephalographic and electroencephalographic power changes showed notable differences which will need to be taken into account to ensure the accurate monitoring of brain state during anaesthesia.


Assuntos
Anestésicos Inalatórios/administração & dosagem , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/diagnóstico por imagem , Estado de Consciência/efeitos dos fármacos , Óxido Nitroso/administração & dosagem , Xenônio/administração & dosagem , Adulto , Córtex Cerebral/fisiologia , Estado de Consciência/fisiologia , Estudos Cross-Over , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/métodos , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética/métodos , Magnetoencefalografia/efeitos dos fármacos , Magnetoencefalografia/métodos , Masculino , Método Simples-Cego , Adulto Jovem
20.
Anesthesiology ; 132(5): 1080-1090, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32101967

RESUMO

BACKGROUND: Neurocognitive investigations suggest that conscious sensory perception depends on recurrent neuronal interactions among sensory, parietal, and frontal cortical regions, which are suppressed by general anesthetics. The purpose of this work was to investigate if local interactions in sensory cortex are also altered by anesthetics. The authors hypothesized that desflurane would reduce recurrent neuronal interactions in cortical layer-specific manner consistent with the anatomical disposition of feedforward and feedback pathways. METHODS: Single-unit neuronal activity was measured in freely moving adult male rats (268 units; 10 animals) using microelectrode arrays chronically implanted in primary and secondary visual cortex. Layer-specific directional interactions were estimated by mutual information and transfer entropy of multineuron spike patterns within and between cortical layers three and five. The effect of incrementally increasing and decreasing steady-state concentrations of desflurane (0 to 8% to 0%) was tested for statistically significant quadratic trend across the successive anesthetic states. RESULTS: Desflurane produced robust, state-dependent reduction (P = 0.001) of neuronal interactions between primary and secondary visual areas and between layers three and five, as indicated by mutual information (37 and 41% decrease at 8% desflurane from wakeful baseline at [mean ± SD] 0.52 ± 0.51 and 0.53 ± 0.51 a.u., respectively) and transfer entropy (77 and 78% decrease at 8% desflurane from wakeful baseline at 1.86 ± 1.56 a.u. and 1.87 ± 1.67 a.u., respectively). In addition, a preferential suppression of feedback between secondary and primary visual cortex was suggested by the reduction of directional index of transfer entropy overall (P = 0.001; 89% decrease at 8% desflurane from 0.11 ± 0.18 a.u. at baseline) and specifically, in layer five (P = 0.001; 108% decrease at 8% desflurane from 0.12 ± 0.19 a.u. at baseline). CONCLUSIONS: Desflurane anesthesia reduces neuronal interactions in visual cortex with a preferential effect on feedback. The findings suggest that neuronal disconnection occurs locally, among hierarchical sensory regions, which may contribute to global functional disconnection underlying anesthetic-induced unconsciousness.


Assuntos
Anestésicos Inalatórios/farmacologia , Comunicação Celular/efeitos dos fármacos , Comunicação Celular/fisiologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiologia , Desflurano/farmacologia , Animais , Córtex Cerebral/citologia , Masculino , Ratos , Ratos Sprague-Dawley , Córtex Visual/citologia , Córtex Visual/efeitos dos fármacos , Córtex Visual/fisiologia
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