Navegando por Palavras-chave "Scopolamine hydrobromide"

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    Alterações plásticas da epileptogênese com ênfase na reorganização colinérgica
    (Universidade Federal de São Paulo (UNIFESP), 2006-01-01) Pereira, Heloisa Aparecida Alves [UNIFESP]; Mello, Luiz Eugenio Araujo de Moraes [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Purpose: We investigated whether the administration of scopolamine, has the ability to interfere in the epileptogenic process and whether this effect could be explained by plastic changes in the cholinergic system. Methods: Two hours after pilocarpine-induced status epilepticus (SE, 320-350 mg/kg, i.p.), male Wistar rats received scopolamine (Pilo+Scopolamine group) 1-2 mg/kg i.p. or saline (Pilo group), every 6 hours for 3 days. After that, osmotic mimipumps were implanted for continuos delivery of scopolamine or saline for an additional 14 days. Animals were videomonitored for 12h/week during the following 3-months period for the occurrence of spontaneous recurrent seizures (SRS) and, thereafter, were perfused, processed and stained for acetylcholnesterase (AChE), neo-Timm and Nissl. Results: Administration of scopolamine decreased the number of SRS and increased latency for seizure onset. There was a decrease in the density of cholinergic positive fibers for AChE in all analised strutures of the Pilo+Scopolamine group as compared with Control and Pilo groups. Treatment with scopolamine however did not interfere with mossy fiber sprouting (MFS). Regression analysis did not indicate an association between SRS frequency and MFS or density of cholinergic fibers. Conclusions: The administration of scopolamine shortly after the inicial precipitant event and for a small period of time, lead to anatomical and functional consequences. Scopolamine interfered with epileptogenesis. However, the structural changes encountered with AChE histochemistry did not explain the epileptogenic and antiepileptogenic processes.
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    Envolvimento dos receptores muscarínicos na memória do contexto e da associação contexto-choque na tarefa do condicionamento do medo ao contexto
    (Universidade Federal de São Paulo (UNIFESP), 2009-08-26) Mazzeo, Ricardo Teixeira [UNIFESP]; Oliveira, Maria Gabriela Menezes de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The cholinergic system participates in the processes of acquisition and consolidation of contextual fear conditioning (CFC), the administration of muscarinic cholinergic antagonist affect both stages of CFC. However it is not clear whether muscarinic receptors are critical for the formation of a memory representation of the context or for the association of such representation with the foot-shock. Through the paradigm of the context pre-exposure facilitation effect, in which the learning about the context is separated from the learning about the context-shock association, the present study examined the effects of dicyclomine and scopolamine on the acquisition and consolidation of context representation and context-shock association. Male Wistar rats were used to verify the dicyclomine effects in the acquisition of CFC, for that it recived an intra-peritoneal injection before pre-exposure or before training. To verify the effects of scopolamine in acquisition and consolidation of CFC, the animals received an intra-hippocampal injection of saline or scopolamine before or after pre-exposure or training. The animals were pre-exposed to context A or B and trained and tested in the context A. The control group (saline-saline), that were pre-exposed to the same context of the training (context A), displayed more freezing time than those pre-exposed to a different context (context B). The treatment with both drugs before the training session impaired the conditioned freezing response of animals pre-exposed to the context A, but the treatment before the pre-exposure session had no effect on freezing response. The treatment with scopolamine after the pre-exposure session impaired performance of animals, but treatment after the training session had no effect on the response of animals. These results suggest that scopolamine and dicyclomine affect the acquisition of CFC, by impairing the learning about context-shock association or the evocation of context representation. Moreover, these drugs do not alter the acquisition of context representation. Treatment with scopolamine interferes with the consolidation of the context representation, without interfering with the consolidation of context-shock association.
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    Influência da aprendizagem e da manipulação do sistema colinérgico muscarínico na sensibilização ao efeito estimulante do etanol
    (Universidade Federal de São Paulo (UNIFESP), 2011-02-21) Takahashi, Shirley [UNIFESP]; Souza-Formigoni, Maria Lucia Oliveira de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Several authors suggest that behavioral sensitization, characterized as psychomotor activity increase in response to psychoactive drugs repeated administration, seems to play a fundamental role in the development of abuse and dependence, increasing the reinforcement property of these substances. Animals that develop sensitization to ethanol differ regarding the binding to some neurotransmitter receptors and also differ regarding the response to the administration of agonists and antagonists of these receptors. Behavioral sensitization is a complex phenomenon that involves different factors, being affected by environment and learning. To evaluate the influence of learning capacity in the sensitization process, in the present study we compared the performance of two groups of mice that presented different levels of sensitization (high and low) in two different learning tasks (appetitive and aversive). We also evaluated the influence of an amnestic drug (scopolamine) in the development and expression of sensitization. It was observed that mice with different levels of sensitization did not differ regarding their learning capacity after chronic treatment with ethanol, in both tasks. Scopolamine, when administered in the dorsal hippocampus simultaneously with ethanol treatment, did not alter the sensitization development. However, when administered subcutaneously it induced higher levels of locomotor activity in those animals that had already developed high sensitization than in low sensitized mice or in the control group. This phenomenon was not observed when scopolamine was administered directly in the nucleus accumbens. When administered in combination with ethanol, it blocked the sensitization. These data suggest that the cholinergic system acts as a neuromodulator in the sensitization process. However, the cholinergic system seems to act in different ways depending on the level of sensitization developed by the animal.