Periodical reactivation under the effect of caffeine attenuates fear memory expression in rats

In the last decade, several studies have shown that fear memories can be attenuated by interfering with reconsolidation. However, most of the pharmacological agents used in preclinical studies cannot be administered to humans. Caffeine is one of the world’s most popular psychoactive drugs and its effects on cognitive and mood states are well documented. Nevertheless, the influence of caffeine administration on fear memory processing is not as clear. We employed contextual fear conditioning in rats and acute caffeine administration under a standard memory reconsolidation protocol or periodical memory reactivation. Additionally, potential rewarding/aversion and anxiety effects induced by caffeine were evaluated by conditioning place preference or open field, respectively. Caffeine administration was able to attenuate weak fear memories in a standard memory reconsolidation protocol; however, periodical memory reactivation under caffeine effect was necessary to attenuate strong and remote memories. Moreover, caffeine promoted conditioned place preference and anxiolytic-like behavior, suggesting that caffeine weakens the initial learning during reactivation through counterconditioning mechanisms. Thus, our study shows that rewarding and anxiolytic effects of caffeine during fear reactivation can change the emotional valence of fear memory. It brings a new promising pharmacological approach based on drugs widely used such as caffeine to treat fear-related disorders

EFEITO RESIDUAL DA ADUBAÇÃO COM ROCHAS BRASILEIRAS COMO FONTES DE POTÁSSIO PARA A CULTURA DA SOJA

A pot experiment was carried out in greenhouse conditions, to evaluate long-term effects of Brazilian rocks as alternative potassium source to soybean BRS 232 in a Rhodic Hapludox and an Ustoxic Quartzipsamment, previously cultivated with sunflower. Treatments were displayed in a factorial scheme (soils x sources x rates), in a completely randomized blocks design with four replications. The rocks volcanic sandstone, alkaline breccia, carbonatite, biotite schist, alkaline ultramaphic, and potassium chloride, as the standard fertilizer source, were applied in rates of 0, 150 e 300 mg kg-1 of K2 O, previously the first crop sowing. At the full bloom stage, yield of shoot dry matter, concentration and accumulation of potassium in plant tissues, besides levels of available K (Mehlich-1) in soil were evaluated. Both yield and potassium accumulation were affected by potassium sources. Alkaline ultramaphic and biotite schist rocks got the highest long-term efficiencies as slow release potassium source and to dry matter yield of soybean. Carbonatite presented slower solubility than the better sources; however it can be used as slow release potassium source. Volcanic sandstone was not a viable potassium source. Mehlich-1 extractor was not suitable to measure available K in soils fertilized with alkaline breccia.O trabalho foi desenvolvido em vasos, em casa-de-vegetação, para avaliar o efeito residual da adubação potássica com rochas moídas sobre o desenvolvimento vegetativo e o acúmulo de potássio (K) por plantas de soja em Latossolo Vermelho distroférrico (LVdf) e Neossolo Quartzarênico (NQ), anteriormente cultivados com girassol. As rochas fontes de potássio, arenito vulcânico, brecha alcalina, carbonatito, biotita xisto e ultramáfica alcalina, além da fonte padrão de K, cloreto de potássio, foram aplicadas nas quantidades de 0, 150 e 300 mg kg-1 de K2 O por ocasião da semeadura do girassol. Avaliou-se a produção de matéria seca da parte aérea das plantas colhidas no florescimento pleno, além das concentrações e o acúmulo de K nos tecidos. Também avaliou-se, ao final do cultivo, o K disponível no solo pelo extrator Mehlich-1. Tanto a produção quanto o acúmulo de K foram influenciados pelas fontes de potássio utilizadas. As rochas ultramáfica alcalina e biotita xisto apresentaram as maiores eficiências agronômicas residuais para a produção de matéria seca e como fonte de liberação lenta de K. O carbonatito apresentou viabilidade de utilização como fonte de K, porém com solubilidade mais lenta que a ultramáfica alcalina e a biotita xisto. O arenito vulcânico não apresentou viabilidade agronômica como fonte de K. O extrator Mehlich-1 não se mostrou adequado para avaliar a disponibilidade de K em solos adubados com a brecha alcalina

Efeitos da administração do antagonista canabinóide AM251 na formação da memória

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Administração de bicuculina intra-hipocampal : interação entre a dose da droga e a intensidade do choque utilizado na tarefa de esquiva inibitória

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Efeito da proteína ligante de cálcio S100B sobre a evocação da memória em ratos

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Memory reconsolidation may be disrupted by a distractor stimulus presented during reactivation

Memories can be destabilized by the reexposure to the training context, and may reconsolidate into a modified engram. Reconsolidation relies on some particular molecular mechanisms involving LVGCCs and GluN2B-containing NMDARs. In this study we investigate the interference caused by the presence of a distractor - a brief, unanticipated stimulus that impair a fear memory expression - during the reactivation session, and tested the hypothesis that this disruptive effect relies on a reconsolidation process. Rats previously trained in the contextual fear conditioning (CFC) were reactivated in the presence or absence of a distractor stimulus. In the test, groups reactivated in the original context with distractor displayed a reduction of the freezing response lasting up to 20 days. To check for the involvement of destabilization / reconsolidation mechanisms, we studied the effect of systemic nimodipine (a L-VGCC blocker) or intra-CA1 ifenprodil (a selective GluN2B/NMDAR antagonist) infused right before the reactivation session. Both treatments were able to prevent the disruptive effect of distraction. Ifenprodil results also bolstered the case for hippocampus as the putative brain structure hosting this phenomenon. Our results provide some evidence in support of a behavioral, non-invasive procedure that was able to disrupt an aversive memory in a long-lasting way

Reduced expression of hippocampal GluN2A-NMDAR increases seizure susceptibility and causes deficits in contextual memory

N-methyl-D-aspartate receptors are heterotetramers composed of two GluN1 obligatory subunits and two regulatory subunits. In cognitive-related brain structures, GluN2A and GluN2B are the most abundant regulatory subunits, and their expression is subjected to tight regulation. During development, GluN2B expression is characteristic of immature synapses, whereas GluN2A is present in mature ones. This change in expression induces a shift in GluN2A/GluN2B ratio known as developmental switch. Moreover, modifications in this relationship have been associated with learning and memory, as well as different pathologies. In this work, we used a specific shRNA to induce a reduction in GluN2A expression after the developmental switch, both in vitro in primary cultured hippocampal neurons and in vivo in adult male Wistar rats. After in vitro characterization, we performed a cognitive profile and evaluated seizure susceptibility in vivo. Our in vitro results showed that the decrease in the expression of GluN2A changes GluN2A/GluN2B ratio without altering the expression of other regulatory subunits. Moreover, rats expressing the anti-GluN2A shRNA in vivo displayed an impaired contextual fear-conditioning memory. In addition, these animals showed increased seizure susceptibility, in terms of both time and intensity, which led us to conclude that deregulation in GluN2A expression at the hippocampus is associated with seizure susceptibility and learning–memory mechanisms.Fil: Acutain, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Griebler Luft, Jordana. Universidade Federal do Rio Grande do Sul; BrasilFil: Vázquez, Cecilia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Popik, Bruno. Universidade Federal do Rio Grande do Sul; BrasilFil: Cercato, Magalí Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Epstein, Alberto. Universite Lyon 2; FranciaFil: Salvetti, Anna. Inserm; FranciaFil: Jerusalinsky, Diana Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: de Oliveira Alvares, Lucas. Universidade Federal do Rio Grande do Sul; BrasilFil: Baez, Maria Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin

Lesões craniofaciais em mulheres vítimas de violência doméstica: estudo retrospectivo

Objetivo: descrever as lesões craniofaciais de acordo com o perfil sociodemográfico e clínico de mulheres vítimas de violência doméstica submetida ao exame do corpo de delito nos registros do instituto médico legal de Anápolis, Goiás de 2015-2018. Método: Trata-se de um estudo descritivo com base em fichas clínicas de mulheres vítimas de violência doméstica. Resultados: Foram identificados 326 inquéritos; predominaram vítimas entre a faixa etária de 21 a 30 anos (32,5%), cor parda (30,4%) e casadas/união estável (38,7%); os principais agressores foram o marido/esposa (58,9%); entre as lesões os tapas e socos (23,7%) foram mais frequentes, sendo a região orbitária (56,1%) a mais afetada, por instrumento contundente (83,4%) e com lesão equimótica (57,4%). Conclusão: Conclui-se que a maior parte das vítimas eram jovens, pardas, casadas, donas de casa e foram agredidas pelo parceiro íntimo. A principal lesão sofrida foi em região orbitária, causada por tapas/socos por instrumento contundente.Objective: Describe craniofacial injuries according to the sociodemographic and clinical profile of women victims of domestic violence submitted to the criminal body examination in the records of the Legal Medical Institute of Anápolis, Goiás, 2015-2018. Method: This is a descriptive study based on clinical records of women victims of domestic violence. Results: 326 inquiries were identified; victims between the age group of 21 to 30 years old (32.5%), brown (30.4%) and married/in a stable relationship (38.7%) predominated; the main aggressors were the husband/wife (58.9%); among injuries, slaps and punches (23.7%) were more frequent, with the orbital region (56.1%) being the most affected, due to a blunt instrument (83.4%) and with ecchymotic lesion (57.4%). Conclusion: It is concluded that the victims were young, brown, married, housewives and were attacked by their intimate partner. The main injury suffered was in the orbital region, caused by slapping/punching by a blunt instrument

Papel do hipocampo e do sistema cabinóide endógeno sobre a reconsolidação de memórias aversivas

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A influência da suplementação de coenzima Q10 sobre o esquema de tratamento medicamentoso de Hipertensão Arterial Sistêmica

Objetivo: Avaliar, através de revisão de literatura, qual o efeito do uso de CoQ10 sobre a dose dos medicamentos hipotensores, quando usados em conjunto. Método: Trata-se de um estudo de revisão da literatura. A busca de artigos foi realizada na base de dados Medline entre os meses de janeiro a março de 2023. Foram utilizados na pesquisa os descritores “hypertension” e “coenzyme Q10”. Resultados: Foram encontrados 17 estudos, mas atenderam aos critérios da pesquisa apenas 2 estudos; em uma publicação os autores descreveram o resultado da administração de CoQ10 a pacientes hipertensos e em outra compilou várias intervenções feitas com o uso de CoQ10 em diferentes cardiopatias. Conclusão: Os estudos que avaliaram a influência da CoQ10 na dose de anti-hipertensivos quando associada ao tratamento padrão mostraram necessidade de menor dose ou de menos medicamentos para controle pressórico