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1.
Therap Adv Gastroenterol ; 16: 17562848231214086, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38078296

RESUMO

Background: Burnout remains a significant health concern within the healthcare sector. Numerous studies have explored burnout among gastroenterologists. However, as far as we are aware, there is currently no documented research specifically focused on burnout for specialists in the field of inflammatory bowel disease (IBD). Objective: The aim of our study was to assess the extent of burnout, its determinants, and to analyze potential risk factors among European healthcare professionals who provide care to patients with IBD. Methods: We carried out a cross-sectional pilot study involving healthcare professionals responsible for the treatment of patients with IBD. A total of 102 participants (56.9% male, average age 48 ± 10.6) completed the anonymous multiple question open web survey. The survey consisted of four distinct psychological constructs (burnout, depression, somatization, and well-being), along with inquiries associated with sociodemographic, health-related, and work-related factors. Results: In our study, we observed that 47.1% of professionals specializing in IBD experienced burnout. When considering all three factors of burnout simultaneously, 5.9% of participants fell within the moderate range. Among these, depersonalization (DP) was the most prevalent factor, with 48% at a medium level and 47.1% at a high level. Depression, somatization, and well-being correlated with emotional exhaustion (EE) and DP, while only depression correlated with personal accomplishment (PA). Furthermore, age, physical activity, total time spent in healthcare, and time spent as an IBD specialist were correlated with EE. Multiple linear regression analysis revealed that depression was the most dominant predictor of both PA and DP. In terms of work-related factors, we observed that having endoscopic access had a detrimental impact on burnout, while the presence of a dedicated IBD outpatient unit and opportunities to participate in multidisciplinary meetings had a positive effect on mitigating burnout. Conclusions: Our pilot study underscores the importance of burnout among IBD professionals in Europe, with a specific emphasis on DP. Subsequent studies may help to uncover the way underlying factors contribute to burnout, potentially laying the foundation for international support and prevention initiative programs.


Burnout among European IBD specialists Professionals working with IBD patients are at high risk of burnout. The prevalence of depersonalization is the highest and there are several other risk factors. However, we also found protective factors that may help to reduce and prevent burnout.

2.
Cogn Res Princ Implic ; 8(1): 15, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36786909

RESUMO

The current study addressed the relationship between subjective memory complaints and negative affect, well-being, and demographic variables by investigating the Hungarian version of Multifactorial Memory Questionnaire. The original factor structure showed a poor fit on our data; therefore, principal component analysis was conducted on data from 577 participants, ranging in age from 18 to 92 years. Our analysis provided a six-component solution: Satisfaction, Retrospective memory mistakes, Prospective memory mistakes, External Strategies, Internal Strategies, and Frustration. To improve the reliability and internal consistency indicators we created four subscales by combining Frustration with Satisfaction, and Retrospective and Prospective memory mistakes subscales. Thus, we were able to preserve the factor structure similar to the original. Subjective memory complaints were correlated positively with anxiety and depression and were associated negatively with well-being. We found a slight positive correlation between age and memory ability, and age was associated negatively with the frequency of external strategy use. Individuals with higher education were satisfied with their memory, used more frequent external strategies. Furthermore, men were more satisfied with their memory and reported better memory ability, while women tended to use more external and internal strategies. Women also showed a higher level of anxiety and depression than men. In conclusion, self-reported memory changes are of particular importance because of their association with perceived mental health status and implications for later disease development.


Assuntos
Metacognição , Masculino , Humanos , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Reprodutibilidade dos Testes , Estudos Retrospectivos , Hungria , Transtornos da Memória/etiologia , Transtornos da Memória/psicologia , Afeto , Inquéritos e Questionários
3.
Heliyon ; 9(1): e12910, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36685410

RESUMO

Cognitive Failures Questionnaire (CFQ) is a widely utilized tool to measure the frequency of everyday cognitive lapses. Here we present a validation study of the Hungarian translation of CFQ. A subsample (n = 157) filled out the questionnaire twice within a 7-21 days interval to determine test-retest reliability. Exploratory structural equation modeling (ESEM) method was run on a larger sample (n = 382) for testing a different number of potential factors. Although the multiple-factor solutions showed good fit, the one-factor solution described the data more adequately. The composite reliability of the final model (CR = .822) as well as test-retest reliability (intraclass correlation coefficient = .900) and the internal consistency (Cronbach's alpha = .920) of the CFQ were high. Higher CFQ scores (i.e., more cognitive slips) correlated positively with anxiety and depression while a negative relationship was present with well-being. Furthermore, women were characterized with higher CFQ scores compared to men. Our results are in line with previous studies, and the excellent psychometric properties make the Hungarian version of CFQ an appropriate measure of cognitive failures.

4.
Sci Rep ; 12(1): 13312, 2022 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922644

RESUMO

The goal of the present study is to examine the cognitive/affective physiological correlates of passenger travel experience in autonomously driven transportation systems. We investigated the social acceptance and cognitive aspects of self-driving technology by measuring physiological responses in real-world experimental settings using eye-tracking and EEG measures simultaneously on 38 volunteers. A typical test run included human-driven (Human) and Autonomous conditions in the same vehicle, in a safe environment. In the spectrum analysis of the eye-tracking data we found significant differences in the complex patterns of eye movements: the structure of movements of different magnitudes were less variable in the Autonomous drive condition. EEG data revealed less positive affectivity in the Autonomous condition compared to the human-driven condition while arousal did not differ between the two conditions. These preliminary findings reinforced our initial hypothesis that passenger experience in human and machine navigated conditions entail different physiological and psychological correlates, and those differences are accessible using state of the art in-world measurements. These useful dimensions of passenger experience may serve as a source of information both for the improvement and design of self-navigating technology and for market-related concerns.


Assuntos
Condução de Veículo , Status Social , Automação , Condução de Veículo/psicologia , Movimentos Oculares , Humanos , Tecnologia
5.
Hum Mov Sci ; 84: 102969, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35704968

RESUMO

Ideomotor theories suggest that different action-effects are not equally important in goal-directed actions, and that task-relevant information are weighted stronger during the representation of actions. This stronger weighting of task-relevant action-effects might also enable to utilize them as retrieval cues of the corresponding motor patterns. The aim of the present study was to investigate how the consistent presence or absence of a sound action-effect influenced the retrieval of the motor components of a simple, everyday action (pinching) as reflected by the pattern of force application and surface electromyogram (sEMG) recorded from the abductor pollicis brevis (APB) and first dorsal interosseous (FDI). Participants applied pairs of pinch impulses to a force sensitive resistor (FSR). The presence or absence of a sound action-effect and the between-action interval (BAI, 2 or 4 s) were manipulated blockwise, whereas the target force level (low or high) was randomly cued from trial to trial. When actions resulted in a sound, force and sEMG activity were reduced. This effect was more pronounced for low target force level trials, which is compatible with a stronger weighting of the sound action-effect when the intensity of the tactile and proprioceptive action-effects is low. Surprisingly, the FDI activity was more variable within actions pairs in the 2 s BAI conditions, which suggests that action pairs separated by the longer time interval might have been represented differently from those separated by the shorter interval.


Assuntos
Gravitação , Músculo Esquelético , Eletromiografia/métodos , Humanos
6.
Biol Psychol ; 159: 108024, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33460782

RESUMO

The N1 event-related potential (ERP) enhancement to auditory transients preceded briefly by another transient has been interpreted as a reflection of latent inhibition, or alternatively, as a superimposing mismatch negativity (MMN) to rare transient event combinations. In a previous study (Volosin, Gaál, & Horváth, 2017a), when rare glides preceded frequent gaps by 150 ms in continuous tones, gap-related N1 was enhanced in younger adults while P2 was attenuated both in younger and older adults, which could be parsimoniously explained by MMN overlap which was delayed with aging. The present study replicated and extended these results with a condition in which the roles of the two event types were reversed. Transients separated by 150 ms elicited delayed MMN in older adults, supporting the MMN interpretation over the latent inhibition account. Furthermore, the divergence of N1 and MMN elicitation patterns demonstrated the independence of N1 and MMN.


Assuntos
Eletroencefalografia , Potenciais Evocados Auditivos , Estimulação Acústica , Idoso , Percepção Auditiva , Potenciais Evocados , Humanos , Tempo de Reação
7.
Brain Res ; 1727: 146565, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31765629

RESUMO

Keeping task-relevant sensory events in the focus of attention while ignoring irrelevant ones is crucial for optimizing task behavior. This attention-distraction balance might change with the perceptual demands of the ongoing task: while easy tasks might be performed with low attentional effort, difficult ones require enhanced attention. The goal of the present study was to investigate how task difficulty affected allocation of attention and distractibility in an auditory distraction paradigm. Participants performed a tone duration discrimination task in which tones were rarely, occasionally presented at a rare pitch (distracters), and task difficulty was manipulated by the duration difference between short and long tones. Short tones were consistently 200 ms long, while long tone duration was 400 ms in the easy, and 260 ms in the difficult condition. Behavioral results and deviant-minus-standard event-related potential (ERP) waveforms suggested similar magnitudes of distraction in both conditions. ERPs without such a subtraction showed that tone onsets were preceded by a negative-going trend, suggesting that participants prepared for tone onsets. In the difficult condition, N1 amplitudes to tone onsets were enhanced, indicating that participants invested more attentional resources. Increased difficulty also slowed down tone offset processing as reflected by significantly delayed offset-related P1 and N1/N2 waveforms. These results suggest that although task difficulty compels participants to attend the tones more strongly, this does not have significant impact on distraction-related processing.


Assuntos
Atenção/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Discriminação Psicológica/fisiologia , Estimulação Acústica , Adulto , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Desempenho Psicomotor , Tempo de Reação , Adulto Jovem
8.
Front Cell Neurosci ; 13: 485, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31736712

RESUMO

Neurotrophins activate Trk receptor signaling to support neuronal survival and many aspects of neuronal function. Early studies demonstrated that TrkA formed a complex with the p75 neurotrophin receptor (p75 NTR ), which increased the affinity and selectivity of NGF binding, however, whether interaction of p75 NTR with other Trk receptors performs a similar function to enhance ligand binding has not been demonstrated. We investigated the interaction of TrkB with full length p75 NTR in hippocampal neurons in response to BDNF and found that the association of these receptors occurs after ligand binding and requires phosphorylation of TrkB, indicating that formation of this receptor complex was not necessary for ligand binding. Moreover, the interaction of these receptors required internalization and localization to early endosomes. We found that association of TrkB with p75 NTR was necessary for optimal downstream signaling of the PI3K-Akt pathway, but not the Erk pathway, in hippocampal neurons. The absence of p75 NTR impaired the ability of BDNF to rescue hippocampal neurons in a trophic deprivation model, suggesting that p75 NTR facilitates the ability of TrkB to activate specific pathways to promote neuronal survival.

9.
eNeuro ; 5(1)2018.
Artigo em Inglês | MEDLINE | ID: mdl-29349290

RESUMO

Neurotrophins play critical roles in the survival, maintenance and death of neurons. In particular, proneurotrophins have been shown to mediate cell death following brain injury induced by status epilepticus (SE) in rats. Previous studies have shown that pilocarpine-induced seizures lead to increased levels of proNGF, which binds to the p75NTR-sortilin receptor complex to elicit apoptosis. A screen to identify compounds that block proNGF binding and uptake into cells expressing p75 and sortilin identified lithium citrate as a potential inhibitor of proNGF and p75NTR-mediated cell death. In this study, we demonstrate that low, submicromolar doses of lithium citrate effectively inhibited proNGF-induced cell death in cultured neurons and protected hippocampal neurons following pilocarpine-induced SE in vivo. We analyzed specific mechanisms by which lithium citrate afforded neuroprotection and determined that lithium citrate prevented the association and internalization of the p75NTR-sortilin receptor complex. Our results demonstrate a novel mechanism by which low-dose treatments of lithium citrate are effective in attenuating p75NTR-mediated cell death in vitro and in vivo.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Morte Celular/efeitos dos fármacos , Citratos/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Receptores de Fator de Crescimento Neural/metabolismo , Animais , Morte Celular/fisiologia , Células Cultivadas , Relação Dose-Resposta a Droga , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Masculino , Neurônios/metabolismo , Neurônios/patologia , Pilocarpina , Ratos , Células Sf9 , Estado Epiléptico/tratamento farmacológico , Estado Epiléptico/metabolismo , Estado Epiléptico/patologia
10.
Sci Rep ; 7(1): 10143, 2017 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-28860638

RESUMO

When background auditory events lead to enhanced auditory event-related potentials (ERPs) for closely following sounds, this is generally interpreted as a transient increase in the responsiveness of the auditory system. We measured ERPs elicited by irrelevant probes (gaps in a continuous tone) at several time-points following rare auditory events (pitch glides) in younger and older adults, who watched movies during stimulation. Fitting previous results, in younger adults, gaps elicited increasing N1 auditory ERPs with decreasing glide-gap separation. N1 increase was paralleled by an ERP decrease in the P2 interval. In older adults, only a glide-gap separation dependent P2 decrease, but no N1-effect was observable. This ERP pattern was likely caused by a fronto-central negative waveform, which was delayed in the older adult group, thus overlapping N1 and P2 in the younger, but overlapping only P2 in the older adult group. Because the waveform exhibited a polarity reversal at the mastoids, it was identified as a mismatch negativity (MMN). This interpretation also fits previous studies showing that gap-related MMN is delayed in older adults, reflecting an age-related deterioration of fine temporal auditory resolution. These results provide a plausible alternative explanation for the ERP enhancement for sounds following background auditory events.


Assuntos
Envelhecimento/fisiologia , Potenciais Evocados Auditivos , Adolescente , Adulto , Idoso , Percepção Auditiva , Feminino , Humanos , Pessoa de Meia-Idade , Tempo de Reação
11.
Neurobiol Aging ; 57: 232-246, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28666708

RESUMO

It has been hypothesized that age-related hearing loss is caused not only by peripheral but also central changes in the auditory system. Many studies used event-related potentials (ERPs) elicited by sound onsets to characterize the age-related differences in central auditory processing. Age-related ERP enhancements in such studies have often been interpreted in terms of elevated sensitivity to auditory stimulation. Such ERPs, however, comprise various components reflecting different aspects of auditory and task-related processing. The composition of the waveforms may considerably differ for ERPs elicited by other auditory events. In the present study, ERPs elicited by tone offsets were used to characterize processing differences between younger and older adults in a short-go, tone-duration discrimination paradigm. Whereas the onset-related auditory ERP was enhanced in the older adult group, no age-related differences were found in the offset-related auditory ERPs observable at temporal electrodes. In older adults, however, offset-related processing was dominated by an N2 that could reflect enhanced cognitive control activities. Because N2 was present regardless discrimination difficulty, younger adults may have framed the task as offset detection, whereas older adults represented the task as "genuine" discrimination.


Assuntos
Estimulação Acústica , Envelhecimento/fisiologia , Envelhecimento/psicologia , Encéfalo/fisiologia , Cognição/fisiologia , Potenciais Evocados Auditivos/fisiologia , Potenciais Evocados/fisiologia , Discriminação da Altura Tonal/fisiologia , Som , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação , Adulto Jovem
12.
Biol Psychol ; 126: 71-81, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28411034

RESUMO

The present study investigated how fast younger and older adults recovered from a distracted attentional state induced by rare, unpredictable sound events. The attentional state was characterized by the auditory N1 event-related potential (ERP), which is enhanced for sound events in the focus of attention. Younger (19-26 years) and older (62-74 years) adults listened to continuous tones containing rare pitch changes (glides) and short gaps. Glides and gaps could be separated in 150ms, 250ms, 650ms or longer and the task was gap detection while ignoring glides. With longer glide-gap separations similar N1 enhancements were observable in both groups suggesting that the duration of the distracted sensory state was not affected by aging. Older adults responded, however, slower at short glide-gap separations which indicated that distraction at subsequent levels of processing may have nonetheless more impact in older than in younger adults.


Assuntos
Estimulação Acústica/psicologia , Fatores Etários , Atenção/fisiologia , Potenciais Evocados/fisiologia , Tempo de Reação/fisiologia , Estimulação Acústica/métodos , Adulto , Idoso , Percepção Auditiva , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Som , Adulto Jovem
13.
Brain Res ; 1639: 120-31, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26947619

RESUMO

The human cognitive system has various functions to enhance performance in tasks requiring responses to stimuli. When potentially occurring stimuli are known, we can establish selective attention sets and ignore task-irrelevant events while attending task-relevant ones. When the stimulation is temporally structured, we can rely on constant temporal relationships between stimulus events to prepare for the task-relevant moments. Most distraction paradigms feature task-irrelevant events which are followed by task-relevant ones within a constant interval, and distraction is induced by randomly replacing some of the standard task-irrelevant events. The constant time interval transforms irrelevant events to task-supportive temporal cues, which are integrated into the task-behavior by the participants. The present study investigated whether distracters could be utilized as temporal cues to support task-related processing in a continuous auditory stimulation paradigm. A continuous tone featuring short and long gaps, and pitch glides was presented. Participants performed a gap duration discrimination task, while ignoring glides. Glides could be presented frequently or rarely. In the informative condition, 80% of the glides predicted the presentation time of the forthcoming gap (400ms), while in the uninformative condition, the occurrence of gaps and glides was independent. Rare glides elicited an enhanced N1, mismatch negativity, and P3 event-related potentials in both informative and uninformative conditions. In informative conditions glides were followed by a contingent negative variation; and rare informative glides elicited an N2b, suggesting that despite triggering distraction-related processes, distracters could be integrated into the task-behavior, and could be utilized as task-supportive cues.


Assuntos
Antecipação Psicológica/fisiologia , Atenção/fisiologia , Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Percepção do Tempo/fisiologia , Estimulação Acústica , Adulto , Sinais (Psicologia) , Discriminação Psicológica/fisiologia , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Adulto Jovem
14.
Int J Psychophysiol ; 92(3): 93-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24657900

RESUMO

Infrequent, salient stimuli often capture attention despite their task-irrelevancy, and disrupt on-going goal-directed behavior. A number of studies show that presenting cues signaling forthcoming deviants reduces distraction, which may be a "by-product" of cue-processing interference or the result of direct preparatory processes for the forthcoming distracter. In the present study, instead of "bursts" of cue information, information on the temporal structure of the stimulus sequence was provided. Young adults performed a spatial discrimination task where complex tones moving left or right were presented. In the predictable condition, every 7th tone was a pitch-deviant, while in the random condition the position of deviants was random with a probability of 1/7. Whereas the early event-related potential correlates of deviance-processing (N1 and MMN) were unaffected by predictability, P3a amplitude was significantly reduced in the predictable condition, indicating that prevention of distraction was based on the knowledge about the temporal structure of the stimulus sequence.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/prevenção & controle , Discriminação Psicológica/fisiologia , Potenciais Evocados Auditivos/fisiologia , Retroalimentação Psicológica/fisiologia , Estimulação Acústica , Adulto , Análise de Variância , Mapeamento Encefálico , Sinais (Psicologia) , Eletroencefalografia , Feminino , Humanos , Masculino , Tempo de Reação , Adulto Jovem
15.
Psychiatr Hung ; 28(4): 370-92, 2013.
Artigo em Húngaro | MEDLINE | ID: mdl-24443573

RESUMO

Mild cognitive impairment (MCI) can be considered as an intermediate stage between normal cognitive aging and dementia. Its screening is extremely important because within a year in 15-20% of cases dementia can evolve. In Hungary, the most widely used screening tool for both dementia and MCI is the Mini Mental State Examination (MMSE), which is often criticized for its poor screening sensitivity of mild dementia and MCI. To eliminate this problem, the Montreal Cognitive Assessment (MoCA) was developed, especially for screening MCI. Our study presents the first results with the Hungarian translation of MoCA. We used Beck Depression Inventory (BDI) for controlling depression. In MoCA the cutoff score between healthy and MCI persons was 24 out of 30. MoCA was more sensitive in detecting MCI than MMSE and its inner consistency was also slightly higher. Specificity of the tests to detect MCI was similar. The results on BDI were not related to either MoCA or MMSE. Our results suggest that MoCA can be a useful tool to detect cognitive decline.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/psicologia , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/psicologia , Demência Vascular/diagnóstico , Demência Vascular/psicologia , Escalas de Graduação Psiquiátrica , Idoso , Idoso de 80 Anos ou mais , Disfunção Cognitiva/epidemiologia , Depressão/complicações , Depressão/epidemiologia , Escolaridade , Feminino , Humanos , Hungria/epidemiologia , Idioma , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/normas , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prevalência , Escalas de Graduação Psiquiátrica/normas , Psicometria , Sensibilidade e Especificidade
16.
Dev Neurobiol ; 72(6): 766-76, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21954122

RESUMO

Neurotrophins can influence multiple cellular functions depending on the cellular context and the specific receptors they interact with. These neurotrophic factors have been extensively studied for their ability to support neuronal survival via Trk receptors and to induce apoptosis via the p75(NTR). However, the p75(NTR) is also detected on cell populations that do not undergo apoptosis in response to neurotrophins. In particular, the authors have detected p75(NTR) expression on astrocytes during development and after seizure-induced injury. In this study, the authors investigated the role of Nerve growth factor (NGF) in regulating astrocyte proliferation and in influencing specific aspects of the cell cycle. The authors have demonstrated that NGF prevents the induction of cyclins and their association with specific cyclin-dependent kinases, and thereby prevents progression through the G1 phase of the cell cycle. Since the authors have previously shown that p75(NTR) but not TrkA, is expressed in astrocytes, these data suggest that activation of p75(NTR) promotes withdrawal of astrocytes from the cell cycle, which may have important consequences during development and after injury.


Assuntos
Astrócitos/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Fator de Crescimento Neural/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Astrócitos/metabolismo , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/fisiologia , Pontos de Checagem do Ciclo Celular/fisiologia , Células Cultivadas , Quinases Ciclina-Dependentes/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Ratos , Ratos Sprague-Dawley , Receptor de Fator de Crescimento Neural/metabolismo
17.
J Neurosci ; 30(46): 15608-15, 2010 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-21084616

RESUMO

Proneurotrophins and mature neurotrophins activate different signaling pathways with distinct effects on their target cells: proneurotrophins can induce apoptotic signaling via p75(NTR), whereas mature neurotrophins activate Trk receptors to influence survival and differentiation. Here, we demonstrate that the PTEN (phosphatase and tensin homolog deleted on chromosome 10) phosphatase represents a novel switch between the survival and apoptotic signaling pathways in rat CNS neurons. Simultaneous activation of p75(NTR) by proNGF and TrkB signaling by BDNF elicited apoptosis despite TrkB phosphorylation. Apoptosis induced by p75(NTR) required suppression of TrkB-induced phosphoinositide-3 kinase signaling, mediated by induction of PTEN, for apoptosis to proceed. Inhibition of PTEN restored the ability of BDNF to phosphorylate Akt and protect cultured basal forebrain neurons from proNGF-induced death. In vivo, inhibition or knockdown of PTEN after pilocarpine-induced seizures protected CNS neurons from p75(NTR)-mediated death, demonstrating that PTEN is a crucial factor mediating the balance between p75(NTR)-induced apoptotic signaling and Trk-mediated survival signaling in brain neurons.


Assuntos
Encéfalo/fisiologia , Fatores de Crescimento Neural/fisiologia , PTEN Fosfo-Hidrolase/biossíntese , Precursores de Proteínas/fisiologia , Receptor trkB/antagonistas & inibidores , Receptor trkB/fisiologia , Receptores de Fator de Crescimento Neural/fisiologia , Transdução de Sinais/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Morte Celular/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Feminino , Masculino , Proteínas do Tecido Nervoso , Neurônios/metabolismo , Neurônios/fisiologia , PTEN Fosfo-Hidrolase/antagonistas & inibidores , PTEN Fosfo-Hidrolase/genética , Gravidez , Ratos , Ratos Sprague-Dawley , Receptores de Fatores de Crescimento
18.
J Neurosci ; 28(39): 9870-9, 2008 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-18815271

RESUMO

Seizure-induced damage elicits a loss of hippocampal neurons mediated to a great extent by the p75 neurotrophin receptor (NTR). Proneurotrophins, which are potent apoptosis-inducing ligands for p75(NTR), were increased in the hippocampus, particularly in astrocytes, by pilocarpine-induced seizures; and infusion of anti-pro-NGF dramatically attenuated neuronal loss after seizures. The p75(NTR) is expressed in many different cell types in the nervous system, and can mediate a variety of different cellular functions by recruiting specific intracellular binding proteins to activate distinct signaling pathways. In this study, we demonstrate that neurotrophin receptor-interacting factor (NRIF) mediates apoptotic signaling via p75(NTR) in hippocampal neurons in vitro and in vivo. After seizure-induced injury, NRIF(-/-) mice showed an increase in p75(NTR) expression in the hippocampus; however, these neurons failed to undergo apoptosis in contrast to wild-type mice. Treatment of cultured hippocampal neurons with proneurotrophins induced association of NRIF with p75(NTR) and subsequent translocation of NRIF to the nucleus, which was dependent on cleavage of the receptor. Neurons lacking NRIF were resistant to p75(NTR)-mediated apoptosis in vitro and in vivo. In addition, we demonstrate some mechanistic differences in p75(NTR) signaling in hippocampal neurons compared with other cell types. Overall, these studies demonstrate the requirement for NRIF to signal p75(NTR)-mediated apoptosis of hippocampal neurons and that blocking pro-NGF can inhibit neuronal loss after seizures.


Assuntos
Apoptose/fisiologia , Hipocampo/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fator de Crescimento Neural/líquido cefalorraquidiano , Fatores de Crescimento Neural/metabolismo , Neurônios/metabolismo , Precursores de Proteínas/líquido cefalorraquidiano , Receptor de Fator de Crescimento Neural/metabolismo , Convulsões/patologia , Animais , Apoptose/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Proteínas de Ligação a DNA , Modelos Animais de Doenças , Ensaio de Desvio de Mobilidade Eletroforética/métodos , Embrião de Mamíferos , Feminino , Fluoresceínas , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Masculino , Camundongos , Camundongos Knockout , Neurônios/efeitos dos fármacos , Compostos Orgânicos/metabolismo , Pilocarpina , Gravidez , Ratos , Convulsões/induzido quimicamente , Fatores de Tempo
19.
J Neurosci ; 26(29): 7756-66, 2006 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-16855103

RESUMO

Proneurotrophins bind with high affinity to p75 neurotrophin receptor (p75NTR) and lack the capacity to bind Trk receptors, suggesting that proneurotrophins can elicit apoptosis via p75NTR even in cells expressing survival-promoting Trk receptors. In the CNS, basal forebrain (BF) neurons are particularly vulnerable to degeneration in Alzheimer's disease, and are among the few populations of brain neurons that express p75NTR throughout life. These neurons also express Trk receptors and may be concomitantly exposed to both proneurotrophins and mature neurotrophins during development, disease, or after injury. We investigated the interaction of mature and proneurotrophin signaling in these CNS neurons. Kainic acid-induced seizures elicited production of pro-NGF by BF astrocytes before caspase activation in p75NTR-positive BF neurons, demonstrating local production of proneurotrophins under pathological conditions and suggesting apoptotic signaling in vivo. Mechanisms of proneurotrophin-induced death were analyzed in cultured BF neurons, and required both p75NTR and its coreceptor sortilin. Surprisingly, exposure to both mature neurotrophins and proneurotrophins demonstrated that Trk phosphorylation did not prevent pro-NGF-induced apoptosis via p75NTR. However, activation of PI3K (phosphatidylinositol 3-kinase)/Akt and MEK (mitogen-activated protein kinase kinase)/Erk pathways prevented pro-NGF-induced apoptosis, revealing a novel critical checkpoint in survival versus apoptotic signaling downstream of Trk activation, and suggesting that pro-NGF blocks survival signaling by preventing Akt and Erk activation. This study shows that proneurotrophins are produced in the brain under pathological conditions, and can elicit apoptosis of BF neurons even when Trk receptors are activated.


Assuntos
Apoptose/fisiologia , Fatores de Crescimento Neural/fisiologia , Neurônios/fisiologia , Prosencéfalo/fisiologia , Precursores de Proteínas/fisiologia , Transdução de Sinais/fisiologia , Proteínas Adaptadoras de Transporte Vesicular , Animais , Sobrevivência Celular/fisiologia , Células Cultivadas , Glicoproteínas de Membrana/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Fosforilação , Prosencéfalo/citologia , Precursores de Proteínas/biossíntese , Receptores Proteína Tirosina Quinases/metabolismo , Receptor de Fator de Crescimento Neural/fisiologia , Spodoptera
20.
Behav Brain Res ; 172(2): 324-32, 2006 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-16814878

RESUMO

The current research studied the behavior adopted in the elevated plus maze (EPM) of rats previously subjected to a social defeat using the resident-intruder paradigm. One day after defeat, intruder animals exhibited an anxiogenic-like behavior in the EPM. In addition, we also evaluated the role of the corticosteroid receptor system (minerlocorticoid - MR - and glucocorticoid - GR - receptors) from the lateral septum (LS) on the anxiety generated by social defeat. The LS is an area of the aversive circuitry that is preferentially activated in passive defensive postures, and participates - together with other brain areas - in the modulation of aversive states. Intruder animals were infused into the LS with the MR or GR antagonist (ZK 91587 and RU 38486, respectively) and then submitted to social stress. All rats were tested in the EPM 1 day later. Only the administration of the GR antagonist, but not the MR antagonist, into the LS normalized the anxiogenic response induced by defeat. Furthermore, we examined whether a single injection of corticosterone (CS) could induce the same influence on the behavior in the EPM as that observed after social defeat. Moreover, we explored the effect of local infusions of MR or GR antagonists into the LS on the behavior exhibited by CS-treated rats in a subsequent EPM exposure. CS administration also exerted an increased anxiogenic-like behavior, which was normalized only by the local infusion of the GR antagonist. Based on these findings, we suggest that CS secreted by emotionally relevant stimuli acting via GR in LS plays an important role in the modulation of the emotional sequelae induced by social defeat.


Assuntos
Ansiedade/metabolismo , Corticosterona/fisiologia , Dominação-Subordinação , Receptores de Glucocorticoides/metabolismo , Núcleos Septais/metabolismo , Análise de Variância , Animais , Aprendizagem da Esquiva/fisiologia , Emoções/fisiologia , Comportamento Exploratório/fisiologia , Feminino , Masculino , Ratos , Ratos Wistar , Receptores de Mineralocorticoides/metabolismo , Meio Social
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