RAQUEL CHACON RUIZ MARTINEZ
Projetos de Pesquisa
Unidades Organizacionais
Instituto de Psiquiatria, Hospital das Clínicas, Faculdade de Medicina
LIM/23 - Laboratório de Psicopatologia e Terapêutica Psiquiátrica, Hospital das Clínicas, Faculdade de Medicina
LIM/23 - Laboratório de Psicopatologia e Terapêutica Psiquiátrica, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
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- Does TRODAT-1 SPECT Uptake Correlate with Cerebrospinal Fluid alpha-Synuclein Levels in Mid-Stage Parkinson's Disease?(2023) COUTINHO, Artur M.; GHILARDI, Maria Gabriela; CAMPOS, Ana Carolina P.; ETCHEBEHERE, Elba; FONOFF, Fernanda C.; CURY, Rubens G.; PAGANO, Rosana L.; MARTINEZ, Raquel C. R.; FONOFF, Erich T.Background: Parkinson's disease (PD) is characterized by a progressive loss of nigrostriatal dopaminergic neurons with impaired motor and non-motor symptoms. It has been suggested that motor asymmetry could be caused due to an imbalance in dopamine levels, as visualized by dopamine transporter single emission computed tomography test (DAT-SPECT), which might be related to indirect measures of neurodegeneration, evaluated by the Montreal Cognitive Assessment (MOCA) and alpha-synuclein levels in the cerebrospinal fluid (CSF). Therefore, this study aimed to understand the correlation between disease laterality, DAT-SPECT, cognition, and alpha-synuclein levels in PD. Methods: A total of 28 patients in the moderate-advanced stage of PD were subjected to neurological evaluation, TRODAT-1-SPECT/CT imaging, MOCA, and quantification of the levels of alpha-synuclein. Results: We found that alpha-synuclein in the CSF was correlated with global cognition (positive correlation, r(2) = 0.3, p = 0.05) and DAT-SPECT concentration in the putamen (positive correlation, r(2) = 0.4, p = 0.005), and striatum (positive correlation, r(2) = 0.2, p = 0.03), thus working as a neurodegenerative biomarker. No other correlations were found between DAT-SPECT, CSF alpha-synuclein, and cognition, thus suggesting that they may be lost with disease progression. Conclusions: Our data highlight the importance of understanding the dysfunction of the dopaminergic system in the basal ganglia and its complex interactions in modulating cognition.
- Effect of Subthalamic Stimulation and Electrode Implantation in the Striatal Microenvironment in a Parkinson's Disease Rat Model(2022) CAMPOS, Ana Carolina Pinheiro; MARTINEZ, Raquel Chacon Ruiz; AUADA, Aline Vivian Vatti; LEBRUN, Ivo; FONOFF, Erich Talamoni; HAMANI, Clement; PAGANO, Rosana LimaDeep brain stimulation (DBS) of the subthalamic nucleus (STN) is considered the gold-standard treatment for PD; however, underlying therapeutic mechanisms need to be comprehensively elucidated, especially in relation to glial cells. We aimed to understand the effects of STN-microlesions and STN-DBS on striatal glial cells, inflammation, and extracellular glutamate/GABAergic concentration in a 6-hydroxydopamine (6-OHDA)-induced PD rat model. Rats with unilateral striatal 6-OHDA and electrodes implanted in the STN were divided into two groups: DBS OFF and DBS ON (5 days/2 h/day). Saline and 6-OHDA animals were used as control. Akinesia, striatal reactivity for astrocytes, microglia, and inflammasome, and expression of cytokines, cell signaling, and excitatory amino acid transporter (EAAT)-2 were examined. Moreover, striatal microdialysis was performed to evaluate glutamate and GABA concentrations. The PD rat model exhibited akinesia, increased inflammation, glutamate release, and decreased glutamatergic clearance in the striatum. STN-DBS (DBS ON) completely abolished akinesia. Both STN-microlesion and STN-DBS decreased striatal cytokine expression and the relative concentration of extracellular glutamate. However, STN-DBS inhibited morphological changes in astrocytes, decreased inflammasome reactivity, and increased EAAT2 expression in the striatum. Collectively, these findings suggest that the beneficial effects of DBS are mediated by a combination of stimulation and local microlesions, both involving the inhibition of glial cell activation, neuroinflammation, and glutamate excitotoxicity.
- Unravelling the Role of Habenula Subnuclei on Avoidance Response: Focus on Activation and Neuroinflammation(2023) ANTUNES, Geiza Fernanda; CAMPOS, Ana Carolina Pinheiro; MARTINS, Daniel de Oliveira; GOUVEIA, Flavia Venetucci; RANGEL JUNIOR, Miguel Jose; PAGANO, Rosana Lima; MARTINEZ, Raquel Chacon RuizUnderstanding the mechanisms responsible for anxiety disorders is a major challenge. Avoidance behavior is an essential feature of anxiety disorders. The two-way avoidance test is a preclinical model with two distinct subpopulations-the good and poor performers-based on the number of avoidance responses presented during testing. It is believed that the habenula subnuclei could be important for the elaboration of avoidance response with a distinct pattern of activation and neuroinflammation. The present study aimed to shed light on the habenula subnuclei signature in avoidance behavior, evaluating the pattern of neuronal activation using FOS expression and astrocyte density using GFAP immunoreactivity, and comparing control, good and poor performers. Our results showed that good performers had a decrease in FOS immunoreactivity (IR) in the superior part of the medial division of habenula (MHbS) and an increase in the marginal part of the lateral subdivision of lateral habenula (LHbLMg). Poor performers showed an increase in FOS in the basal part of the lateral subdivision of lateral habenula (LHbLB). Considering the astroglial immunoreactivity, the poor performers showed an increase in GFAP-IR in the inferior portion of the medial complex (MHbl), while the good performers showed a decrease in the oval part of the lateral part of the lateral complex (LHbLO) in comparison with the other groups. Taken together, our data suggest that specific subdivisions of the MHb and LHb have different activation patterns and astroglial immunoreactivity in good and poor performers. This study could contribute to understanding the neurobiological mechanisms responsible for anxiety disorders.
- Detection of a Temporal Error Triggers Reconsolidation of Amygdala-Dependent Memories(2013) DIAZ-MATAIX, Lorenzo; MARTINEZ, Raquel Chacon Ruiz; SCHAFE, Glenn E.; LEDOUX, Joseph E.; DOYERE, ValerieUpdating memories is critical for adaptive behaviors, but the rules and mechanisms governing that process are still not well defined. During a limited time window, the reactivation of consolidated aversive memories triggers memory lability and induces a plasticity-dependent reconsolidation process in the lateral nucleus of amygdala (LA) [1-5]. However, whether new information is necessary for initiating reconsolidation is not known. Here we show that changing the temporal relationship between the conditioned stimulus (CS) and unconditioned stimulus (US) during reactivation is sufficient to trigger synaptic plasticity and reconsolidation of an aversive memory in the LA. These findings demonstrate that time is a core part of the CS-US association and that new information must be presented during reactivation in order to trigger LA-dependent reconsolidation processes. In sum, this study provides new basic knowledge about the precise rules governing memory reconsolidation of aversive memories that might be used to treat traumatic memories.