PPG - Biologia Química

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https://hdl.handle.net/11600/61107

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Navegando PPG - Biologia Química por Palavras-chave "5HT1A"

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    Modulação do extrato padronizado de Ginkgo biloba na expressao dos receptores NMDA-NR2B e 5HT1A e de astrócitos em diferentes regiões da formação hipocampal doral de ratos submetidos à aquisição da supressão condicionada da resposta lamber
    (Universidade Federal de São Paulo, 2014-09-25) Tilger, Myrcea Andressa de Souza [UNIFESP]; Cerutti, Suzete Maria [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The brain’s ability to adapt and change its structure, connectivity and functional properties over time characterizes neural plasticity, which can be investigated using different approaches. Memory formation has been recognized as a stimulant of brain plasticity, which is often characterized by neuronal and glial adaptations. Our group has been evaluated neural plasticity by means of the analysis of behavioural and morphological correlates. The present study investigated the astroglial reaction employing glial fibrillary acidic protein immunohistochemistry (GFAP-IR) in the hippocampal formation. (CA1, CA3 and GD) with one dose before fear conditioning of EGb (250 mg.Kg-1, 500 mg.Kg-1 and 1000 mg.Kg-1),vehicle (Tween® and Saline), agonists (10.0mg.Kg-1 Buspirone or 10mg.Kg-1N-methyl D-aspartate), antagonists (0.3 mg.Kg-1 (S)-WAY 100135 or 3.0 mg.Kg-1Ro25-6981) of the 5-HT1ARs or NMDARs/GluN2B and antagonists+EGb ((S)-WAY+EGb or Ro+EGb) (n=3/group). Further, negative control groups (saline 0.9% i.p. and Tween 80 12% v.o.), no-footshock group (CS) and conditioned group (CS-US association) were used. Twenty-four hours after the behavioral experiments were performed, the rats (n=3/group) were deeply anesthetized and perfused with 4% paraformaldehyde. After decapitation, the brains were removed, post fixed, cryoprotected in 10% sucrose, frozen and stored at -80ºC until use. Adjacent serial 20-µm-thick coronal brain sections were obtained with a cryostat and mounted on gelatin-coated slices. These sections integrated two levels including formation hippocampal rostral and caudal (coordinates -2.04 to-4.20 mm from bregma). At each region, 4 fields were analyzed bilaterally. Images were acquired using AxioVision software (Carl Zeiss, Axion imager A2). ImageJ software was employed for quantification of the immunoreactive labeling in CA1, CA3 and GD. An increased number of GFAP-IR astrocytes were found in the CA1, CA3 and GD (P<0.05) of the EGb groups. GFAP-IR was increased in the CA3 and GD in Buspirone group (P<0.05). However, no significant changes were observed to NMDA groups (P>0.05). Additionally, the overexpression of GFAP was reversed by treatment with (S)-WAY 100135 or Ro25-6981 prior EGb. Our results provide further evidence that astroglial reaction in the hippocampal formation may be involved in neuroplastic response in those regions. The fear memory/treatment-dependent changes suggest that EGb might be effective for memory enhancement through its effect on the astrocytes cells which seems to be modulate by NMDA-type of glutamate as well as by serotoninergic-type5HT1A receptors.