Navegando por Palavras-chave "GABA(A)"

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    GABA and opioid binding distribution in the brain of the seizure-resistant Proechimys guyannensis: An autoradiography study
    (Wiley-Blackwell, 2006-10-01) Rocha, Luisa; Arida, Ricardo Mario; Carvalho, Reinaldo de Amorim; Scorza, Fulvio Alexandre; Neri-Bazan, Leticia; Cavalheiro, Esper Abrao; Ctr Res & Adv Studies; Universidade Federal de São Paulo (UNIFESP)
    Proechimys guyannensis rodents present resistance to epilepsy. Autoradiography was used to map GABA(A) (H-3-Muscimol), benzodiazepine (H-3-Flunitrazepam), mu (H-3-DAMGO), and delta (H-3-DPDPE) opioid receptor binding in adult Proechimys guyannensis brain under normal conditions. Results were compared with values obtained from adult Wistar rats. Proechimys presented reduced 3H-Muscimol binding in several cortices, thalamus, medial amygdala nucleus, and dorsal dentate gyrus. H-3-Flunitrazepam binding was reduced in periaqueductal gray, frontal and entorhinal cortices, and enhanced in piriform cortex and ventral CA2 field of Ammons horn. Concerning H-3-DAMGO binding, high values were found in several cortices, medial amygdala nucleus, dorsal dentate gyrus, and periaqueductal gray, whereas reduced binding was detected in anterior olfactory tubercle, cingulated cortex, thalamus, basolateral amygdala, substantia nigra, and dorsal and ventral CA fields. High H-3-DPDPE binding was noticed in CA1 field from dorsal hippocampus, while reduced values were found in cingulate cortex, olfactory tubercle, thalamus, and substantia nigra. These findings provide the first description of receptor binding distribution of the Proechimys brain and suggest natural endogenous anticonvulsant mechanisms of theses rodents under normal conditions.
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    Rats with different thresholds for DMCM-induced clonic convulsions differ in the sleep-time of diazepam and [H-3]-Ro 15-4513 binding
    (Elsevier B.V., 2012-02-01) Contó, Marcos Brandão [UNIFESP]; Hipólide, Débora Cristina [UNIFESP]; Barbosa de Carvalho, Jose Gilberto [UNIFESP]; Venditti, Marco Antonio Campana [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The current study investigated the possible inherent relationship between convulsions and sleep involving the GABA(A)/benzodiazepine site complex. the aim of this study was to determine if rats with high (HTR) and low (LTR) thresholds for clonic convulsions induced by DMCM, a benzodiazepine inverse agonist, differ in the following aspects: (1) sensitivity to the hypnotic effects of the GABA(A) positive allosteric modulators diazepam, pentobarbital and ethanol and (2) in the binding of [H-3]-flunitrazepam, a benzodiazepine agonist, measured by autoradiography, and [H-3]-Ro 15-4513, a benzodiazepine partial inverse agonist, to membranes from discrete brain regions. the LTR subgroup presented a shorter diazepam-induced sleeping time compared to that of the HTR subgroup. Biochemical assays revealed that the LTR subgroup did not differ in [H-3]-flunitrazepam binding compared to the HTR subgroup. With respect to the binding of [H-3]-Ro 15-4513, the LTR subgroup had higher binding in the brainstem and lower binding in the striatum compared to the HTR subgroup. These results suggest that differences in the benzodiazepine site on the GABA(A) receptor may underlie the susceptibility to DMCM-induced convulsions and sensitivity to the hypnotic effect of diazepam. (C) 2011 Elsevier B.V. All rights reserved.