Publications by authors named "Nilton Barreto Dos Santos"

Studies investigated how stressful experiences modulate physiological and behavioral responses and the consequences of stress-induced corticosterone release in anxiety-like behavior. Adolescence is crucial to brain maturation, and several neurobiological changes in this period lead individuals to increased susceptibility or resilience to aversive situations. Despite the effects of stress in adults, information about adolescents' responses to acute stress is lacking.

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Background And Aim: Cortisol binds to mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) found in the hippocampus. The balanced expression of these receptors is essential to neuronal survival as MR and GR activations have antiapoptotic and proapoptotic effects, respectively. Given the aging changes in dogs' dentate gyrus (DG) and the possible involvement of cortisol receptors in this process, this study aimed to evaluate the expression of MR and GR and neuronal degeneration in this hippocampal region of aged dogs.

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Background: Knowledge on the neurobiological systems underlying psychiatric disorders has considerably evolved due to findings on basic research using animal models. Anxiety-like behaviors in rodents are widely explored in neuroethological apparatuses, such as the light-dark box (LDB) test through different protocols, which have been shown to influence the behavioral outcomes and probably the activation of the hypothalamic-pituitary-adrenal (HPA) axis.

New Method: Adult male Wistar rats were submitted to LDB in different room illumination conditions (25/0, 65/0 and/or 330/0 lux), initial positioning in the LDB compartments and previous stressful experience in the Elevated Plus Maze (EPM) or restraint stress (RS).

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Article Synopsis
  • COVID-19 has led to over a million deaths globally, with significant gaps in understanding its neurological effects, despite known lung disease mechanisms.
  • The study analyzed changes in brain cells (astrocytes) from Syrian hamsters infected with SARS-CoV-2, revealing disruptions in metabolic processes related to carbon metabolism and glycolysis, linked to neurological disorders.
  • Findings indicate that SARS-CoV-2 affects brain regions like the hippocampus and cortex, potentially leading to neurological symptoms such as memory loss and cognitive impairment in infected individuals.
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Previous studies have suggested that the basolateral amygdala (BLA) and the ventral hippocampus (VH) are critical sites for predator-related fear memory. Predator exposure is an intense emotional experience and should increase plasmatic corticosterone likely to modulate the emotion-related memories. However, it is unclear whether the BLA and VH harbor plastic events underlying predator-related fear memory storage and how molecular and endocrine mechanisms interact to modulate memory to the predatory threat.

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  • The embryonic stage is a critical period for congenital abnormalities, with the central nervous system being particularly vulnerable to genetic, environmental, and epigenetic factors.
  • A study investigated the impact of environmental tobacco smoke (ETS) on neuroinflammation in offspring from pregnant mice, exposing them to cigarette smoke and assessing the effects on their immune response.
  • Results showed that mouse pups exposed to ETS had increased proinflammatory cytokines and decreased cell viability, suggesting that ETS may worsen neuroinflammation-related conditions later in life.
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Alcohol use disorder is one of the most prevalent addictions, strongly influenced by environmental factors. Voluntary physical activity (VPA) has proven to be intrinsically reinforcing and we hypothesized that, as a non-drug reinforcer, VPA could mitigate ethanol-induced rewarding effects. The transcriptional factor cAMP response element binding protein (CREB), and deacetylases isozymes sirtuins 1 and 2 (SIRT-1 and SIRT-2) have a complex interplay and both play a role in the rewarding effects of ethanol.

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Zika virus (ZIKV) is a flavivirus linked to multiple birth defects including microcephaly, known as congenital ZIKV syndrome. The identification of host factors involved in ZIKV replication may guide efficacious therapeutic interventions. In genome-wide transcriptional studies, we found that ZIKV infection triggers aryl hydrocarbon receptor (AHR) activation.

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Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of an array of enzymes with important detoxifying and antioxidant functions. Current findings support the role of high levels of oxidative stress in the pathogenesis of neurological disorders. Given the central role played by Nrf2 in counteracting oxidative damage, a number of studies have targeted the modulation of this transcription factor in order to confer neuroprotection.

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Chronic psychogenic stress can increase neuronal calcium influx and generate the intracellular accumulation of oxidative (ROS) and nitrosative (RNS) reactive species, disrupting synaptic transmission in the brain. These molecules impair the Na,K-ATPase (NKA) activity, whose malfunction has been related to neuropsychiatric disorders, including anxiety, depression, schizophrenia, and neurodegenerative diseases. In this study, we assessed how 14 days of restraint stress in rats affect NKA activity via oxidative/nitrosative damage in the frontal cortex (FCx), a crucial region for emotional and cognitive control.

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Previous studies showed that acute restraint stress or transient elevation of glucocorticoid (GC) stress hormones produces emergent changes in both anxiety behavior and dendritic branches in the basolateral amygdala complex (BLA) of rats. In this work, we demonstrate that exposure to environmental enrichment (EE) prevented stress-induced increases in anxiety (emerging 10 days post-stress) in adult rats without blocking stress-induced dendritic branch remodeling in the BLA nor stress-induced enhancement of GC serum levels.

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Article Synopsis
  • Environmental enrichment (EE) enhances interactions with various stimuli for animals, leading to reduced stress-induced anxiety, which is linked to changes in brain structures like the hippocampus and basolateral amygdala (BLA).
  • A study found that EE can prevent anxiety-like symptoms in rats immediately after acute stress without altering corticosterone levels, indicating a distinct protective mechanism.
  • The research revealed that EE exposure reduces the hyperactivity of BLA neurons and the expression of EGR-1, suggesting that this could be a key factor in how EE helps mitigate stress-related anxiety.
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