Navegando por Autor "Reis, Marina Pádua"

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Diazepam causes sedative rather than anxiolytic effects in C57BL/6J mice
(Springer Science and Business Media LLC, 2021-04-29) Reis, Marina Pádua; Ferreira, Diana Aline Nôga Morais; Tort, Adriano Bretanha Lopes; Blunder, Martina
Diazepam has been broadly accepted as an anxiolytic drug and is often used as a positive control in behavioral experiments with mice. However, as opposed to this general assumption, the effect of diazepam on mouse behavior can be considered rather controversial from an evidence point of view. Here we revisit this issue by studying the effect of diazepam on a benchmark task in the preclinical anxiety literature: the elevated plus maze. We evaluated the minute-by-minute time-course of the diazepam effect along the 10 min of the task at three different doses (0.5, 1 and 2 mg/kg i.p. 30 min before the task) in female and male C57BL/6J mice. Furthermore, we contrasted the effects of diazepam with those of a selective serotoninergic reuptake inhibitor (paroxetine, 10 mg/kg i.p. 1 h before the task). Diazepam had no anxiolytic effect at any of the tested doses, and, at the highest dose, it impaired locomotor activity, likely due to sedation. Noteworthy, our results held true when examining male and female mice separately, when only examining the first 5 min of the task, and when animals were subjected to one hour of restrain-induced stress prior to diazepam treatment. In contrast, paroxetine significantly reduced anxiety-like behavior without inducing sedative effects. Our results therefore suggest that preclinical studies for screening new anxiolytic drugs should be cautious with diazepam use as a potential positive control
Estudo do envolvimento do córtex perirrinal na reconsolidação da memória de reconhecimento de objetos
(2019-03-14) Reis, Marina Pádua; Cammarota, Martin Pablo; ; ; Laplagne, Diego Andres; ; Luchiari, Ana Carolina; ; Katche, Cynthia Lorena; ; Barbosa, Flávio Freitas;
Memórias reativadas podem se tornar lábeis e, para persistir, necessitam passar por um processo de reestabilização dependente de síntese proteica chamado reconsolidação. A ocorrência da reconsolidação é restrita a determinadas condições, que não são totalmente conhecidas e variam entre os tipos de memória. O córtex perirrinal (cPER), uma estrutura do lobo temporal que recebe diversas aferências sensoriais e possui conexões recíprocas com o hipocampo, tem sido relacionado à reconsolidação da memória de reconhecimento de objetos (MRO). No entanto, sua função nesse processo é ainda controversa. Usando uma tarefa de reconhecimento de objetos, neste trabalho nós investigamos o envolvimento do córtex perirrinal na reconsolidação da MRO. Infusões do inibidor de síntese proteica anisomicina diretamente no cPER causaram déficit na MRO quando administradas após sua reativação na presença de um único objeto familiar, mas não na presença de dois objetos familiares ou um objeto familiar acompanhado de um novo. Estes resultados foram replicados também através do bloqueio de receptores glutamatérgicos N-metil D-Aspartato (rNMDA) atréves de infusões intra-perirrinais do antagonista glutamatérgico AP5. Análises de imunofluorescencia revelaram um aumento proeminente na expressão perirrinal de ZIF268 somente após a reativação da MRO pela apresentação de um único objeto familiar. Nós também encontramos que o nocaute da expressão de ZIF268 por oligonucleotídeos anti - senso, no cPER, prejudicam a reconsolidação da MRO. Juntos, esses resultados revelam uma condição limitante para a reconsolidação da MRO que envolve a percepção parcial ou incompleta de dicas de reconhecimento durante a reativação, a síntese de proteínas, a atividade de rNMDA e a expressão de Zif-268 no cPER.
Hippocampal Cb2 receptors: an untold story
(2021-10-29) Visvanathar, Robin; Papanikolaou, Maria; Nôga, Diana Aline; Reis, Marina Pádua; Tort, Adriano Bretanha Lopes; Blunder, Martina
The field of cannabinoid research has been receiving ever-growing interest. Ongoing debates worldwide about the legislation of medical cannabis further motivates research into cannabinoid function within the central nervous system (CNS). To date, two wellcharacterized cannabinoid receptors exist. While most research has investigated Cb1 receptors (Cb1Rs), Cb2 receptors (Cb2Rs) in the brain have started to attract considerable interest in recent years. With indisputable evidence showing the wide-distribution of Cb2Rs in the brain of different species, they are no longer considered just peripheral receptors. However, in contrast to Cb1Rs, the functionality of central Cb2Rs remains largely unexplored. Here we review recent studies on hippocampal Cb2Rs. While conflicting results about their function have been reported, we have made significant progress in understanding the involvement of Cb2Rs in modulating cellular properties and network excitability. Moreover, Cb2Rs have been shown to be expressed in different subregions of the hippocampus, challenging our prior understanding of the endocannabinoid system. Although more insight into their functional roles is necessary, we propose that targeting hippocampal Cb2Rs may offer novel therapies for diseases related to memory and adult neurogenesis deficits
Recognition memory reconsolidation requires hippocampal Zif268
(2019-11-12) Gonzalez, Maria Carolina; Rossato, Janine I.; Radiske, Andressa; Reis, Marina Pádua; Cammarota, Martín Pablo
Object recognition memory (ORM) serves to distinguish familiar items from novel ones. Reconsolidation is the process by which active memories are updated. The hippocampus is engaged in ORM reconsolidation through a mechanism involving induction of long-term potentiation (LTP). The transcription factor Zif268 is essential for hippocampal LTP maintenance and has been frequently associated with memory processes. However, its possible involvement in ORM reconsolidation has not been determined conclusively. Using Zif268 antisense oligonucleotides in combination with behavioural, biochemical and electrophysiological tools in rats, we found that hippocampal Zif268 is necessary to update ORM through reconsolidation but not to retrieve it or keep it stored. Our results also suggest that knocking down hippocampal Zif268 during ORM reconsolidation deletes the active recognition memory trace.

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Navegando por Autor "Reis, Marina Pádua"