Navegando por Palavras-chave "Restraint"
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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.
- ItemAcesso aberto (Open Access)c-Fos expression induced by electroacupuncture at the Zusanli point in rats submitted to repeated immobilization(Associação Brasileira de Divulgação Científica, 2003-12-01) Medeiros, M.a.; Canteras, N.s.; Suchecki, Deborah [UNIFESP]; Mello, Luiz Eugenio Araujo de Moraes [UNIFESP]; Universidade Federal Rural do Rio de Janeiro Departamento de Ciências Fisiológicas; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)In laboratory animals, acupuncture needs to be performed on either anesthetized or, if unanesthetized, restrained subjects. Both procedures up-regulate c-Fos expression in several areas of the central nervous system, representing therefore a major pitfall for the assessment of c-Fos expression induced by electroacupuncture. Thus, in order to reduce the effect of acute restraint we used a protocol of repeated restraint for the assessment of the brain areas activated by electroacupuncture in adult male Wistar rats weighing 180-230 g. Repeated immobilization protocols (6 days, 1 h/day and 13 days, 2 h/day) were used to reduce the effect of acute immobilization stress on the c-Fos expression induced by electroacupuncture at the Zusanli point (EA36S). Animals submitted to immobilization alone or to electroacupuncture (100 Hz, 2-4 V, faradic wave) in a non-point region were compared to animals submitted to electroacupuncture at EA36S (4 animals/subgroup). c-Fos expression was measured in 41 brain areas by simple counting of cells and the results are reported as number of c-Fos-immunoreactive cells/10,000 µm². The protocols of repeated immobilization significantly reduced the immobilization-induced c-Fos expression in most of the brain areas analyzed (P < 0.05). Animals of the EA36S groups had significantly higher levels of c-Fos expression in the dorsal raphe nucleus, locus coeruleus, posterior hypothalamus and central medial nucleus of the thalamus. Furthermore, the repeated immobilization protocols intensified the differences between the effects of 36S and non-point stimulation in the dorsal raphe nucleus (P < 0.05). These data suggest that high levels of stress can interact with and mask the evaluation of specific effects of acupuncture in unanesthetized animals.