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Navegando ISS - Artigos por Autor "Abrão, Renata Oliveira [UNIFESP]"
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- ItemSomente MetadadadosAcute restraint differently alters defensive responses and fos immunoreactivity in the rat brain(Elsevier B.V., 2012-06-15) Andrade, José Simões de [UNIFESP]; Abrão, Renata Oliveira [UNIFESP]; Céspedes, Isabel Cristina [UNIFESP]; Garcia, Marcia Carvalho [UNIFESP]; Nascimento, Juliana Olivetti Guzman [UNIFESP]; Spadari-Bratfisch, Regina Celia [UNIFESP]; Melo-Thomas, Liana [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Viana, Milena de Barros [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Results from a previous study show that rats exposed to acute restraint display anxiogenic-like behavior, evidenced by facilitation of avoidance responses in the elevated T-maze (ETM) model of anxiety. in contrast, escape responses were unaltered by stress exposure. Since ETM avoidance and escape tasks seem to activate distinct sets of brain structures, it is possible that the differences observed with acute restraint are due to particularities in the neurobiological mechanisms which modulate these responses. in the present study, analysis of fos protein immunoreactivity (fos-ir) was used to map areas activated by exposure of male Wistar rats to restraint stress (30 min) previously (30 min) to the ETM. Corticosterone levels were also measured in stressed and non-stressed animals. Confirming previous observations restraint facilitated avoidance performance, an anxiogenic result, while leaving escape unaltered. Performance of the avoidance task increased fos-ir in the frontal cortex, intermediate lateral septum, basolateral amygdala, basomedial amygdala, lateral amygdala, anterior hypothalamus and dorsal raphe nucleus. in contrast, performance of escape increased fos-ir in the ventromedial hypothalamus, dorsolateral periaqueductal gray and locus ceruleus. Both behavioral tasks also increased fos-ir in the dorsomedial hypothalamus. Restraint significantly raised corticosterone levels. Additionally after restraint, fos-ir was predominantly seen in the basolateral amygdala and dorsal raphe of animals submitted to the avoidance task. This data confirms that different sets of brain structures are activated by ETM avoidance and escape tasks and suggests that acute restraint differently alters ETM behavior and the pattern of fos activation in the brain. (C) 2012 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosChronic unpredictable mild stress alters an anxiety-related defensive response, Fos immunoreactivity and hippocampal adult neurogenesis(Elsevier B.V., 2013-08-01) Andrade, José Simões de [UNIFESP]; Céspedes, Isabel Cristina [UNIFESP]; Abrão, Renata Oliveira [UNIFESP]; Santos, Thays Brenner dos [UNIFESP]; Diniz, Leila [UNIFESP]; Britto, Luiz Roberto Giorgetti de; Spadari-Bratfisch, Regina Celia [UNIFESP]; Ortolani, Daniela [UNIFESP]; Melo-Thomas, Liana [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Viana, Milena de Barros [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Previous results show that elevated T-maze (ETM) avoidance responses are facilitated by acute restraint. Escape, on the other hand, was unaltered. To examine if the magnitude of the stressor is an important factor influencing these results, we investigated the effects of unpredictable chronic mild stress (UCMS) on ETM avoidance and escape measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to map areas activated by stress exposure in response to ETM avoidance and escape performance. Additionally, the effects of the UCMS protocol on the number of cells expressing the marker of migrating neuroblasts doublecortin (DCX) in the hippocampus were investigated. Corticosterone serum levels were also measured. Results showed that UCMS facilitates ETM avoidance, not altering escape. in unstressed animals, avoidance performance increases Fos-ir in the cingulate cortex, hippocampus (dentate gyrus) and basomedial amygdala, and escape increases Fos-ir in the dorsolateral periaqueductal gray and locus ceruleus. in stressed animals submitted to ETM avoidance, increases in Fos-ir were observed in the cingulate cortex, ventrolateral septum, hippocampus, hypothalamus, amygdala, dorsal and median raphe nuclei. in stressed animals submitted to ETM escape, increases in Fos-ir were observed in the cingulate cortex, periaqueductal gray and locus ceruleus. Also, UCMS exposure decreased the number of DCX-positive cells in the dorsal and ventral hippocampus and increased corticosterone serum levels. These data suggest that the anxiogenic effects of UCMS are related to the activation of specific neurobiological circuits that modulate anxiety and confirm that this stress protocol activates the hypothalamus-pituitary-adrenal axis and decreases hippocampal adult neurogenesis. (C) 2013 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosCRF family peptides are differently altered by acute restraint stress and chronic unpredictable stress(Elsevier B.V., 2014-09-01) Andrade, José Simões de [UNIFESP]; Viana, Milena de Barros [UNIFESP]; Abrão, Renata Oliveira [UNIFESP]; Bittencourt, Jackson C.; Céspedes, Isabel Cristina [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Corticotropin-releasing factor (CRF) acts to promote stress-like physiological and behavioral responses and is mainly expressed in the paraventricular hypothalamic nucleus (PVN). Urocortin 1 (Ucn1) is also a ligand to CRF type 1 and 2 receptors that has been associated with the stress response. Ucnl neurons are primarily found in the Edinger-Westphal (EW) nucleus. It has been previously proposed that CRF and Ucnl differently modulate stress responses to distinct types of stressors. the present study used male Wistar rats to compare the effects of acute restraint stress and unpredictable chronic stress (UCS) through Fos-immunoreactivity (Fos-ir) on CRF-containing neurons of PVN and Ucn1-containing EW centrally projecting neurons. Results showed that PVN neurons responded to both acute restraint and UCS. Also for the PVN, unspecific variables, dependent on the time animals remained in the laboratory, do not seem to alter Fos-ir, since no significant differences between acute and chronic control groups were found. On the other hand, EW neurons were only activated in response to acute restraint stress. Also, for this nucleus a significant difference was found between acute and chronic control groups, suggesting that unspecific variables, dependent on the time animals remain in the laboratory, interfere with the nucleus activation. These results suggest that CRF/Ucn1 neuronal circuits encompass two interconnected systems, which are coordinated to respond to acute stressors, but are differentially activated during chronic unpredictable stress. (C) 2014 Elsevier B.V. All rights reserved.