Base de dados : LILACS
Pesquisa : B01.050.500.644.400.060 [Categoria DeCS]
Referências encontradas : 3 [refinar]
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Texto completo SciELO Brasil
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Id: lil-309199
Autor: Kerchove, C. M; Markus, R. P; Freitas, J. C; Costa-Lotufo, L. V.
Título: Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia)
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;35(4):485-491, Apr. 2002. ilus.
Idioma: en.
Resumo: Trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. In the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. In rat jejunum the contractile response induced by trimethylsulfonium (pD2 = 2.46 + or - 0.12 and maximal response = 2.14 + or - 0.32 g) was not antagonized competitively by atropine. The maximal response (Emax) to trimethylsulfonium was diminished in the presence of increasing doses of atropine (P<0.05), suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. Trimethylsulfonium displaced [³H]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (Ki = 0.5 mM). Furthermore, it caused contraction of frog rectus abdominis muscles (pD2 = 2.70 + or - 0.06 and Emax = 4.16 + or - 0.9 g), which was competitively antagonized by d-tubocurarine (1, 3 or 10 æM) with a pA2 of 5.79, suggesting a positive interaction with nicotinic receptors. In fact, trimethylsulfonium displaced [³H]-nicotine from rat diaphragm muscle membranes with a Ki of 27.1 æM. These results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively
Descritores: Aplysia
Colinérgicos
Agonistas Nicotínicos
Receptores Muscarínicos
Receptores Nicotínicos
-Atropina
Relação Dose-Resposta a Droga
Contração Muscular
Ratos Wistar
Limites: Animais
Masculino
Ratos
Responsável: BR1.1 - BIREME


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Texto completo SciELO Brasil
Melo, V. M. M
Vasconcelos, I. M
Carvalho, A. F. F. U
Texto completo
Id: lil-210967
Autor: Melo, V. M. M; Fonseca, A. M; Vasconcelos, I. M; Carvalho, A. F. F. U.
Título: Toxic, antimicrobial and hemagglutinating activities of the purple fluid of the sea hare Aplysia dactylomela Rang, 1828
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;31(6):785-91, jun. 1998. ilus, tab.
Idioma: en.
Resumo: The antimicrobial, hemagglutinating and toxic activities of the purple fluid of the sea hare Aplysia dactylomela are described. Intact or dialyzed purple fluid inhibited the growth of species of Gram-positive and Gram-negative bacteria and the action was not bactericidal but bacteriostatic. The active factor or factors were heat labile and sensitive to extreme pH values. The fluid preferentially agglutinated rabbit erythrocytes and, to a lesser extent, human blood cells, and this activity was inhibited by the glycoprotein fetuin, a fact suggesting the presence of a lectin. The fluid was also toxic to brine shrimp nauplii (LD 50 141.25 µg protein/ml) and to mice injected intraperitoneally (LD 50 201.8 ñ 8.6 mg protein/kg), in a dose-dependent fashion. These toxic activities were abolished when the fluid was heated. Taken together, the data suggest that the activities of the purple fluid are due primarily to substance(s) of a protein nature which may be involved in the chemical defense mechanism of this sea hare
Descritores: Aplysia
Bactérias/efeitos dos fármacos
Líquidos Corporais
Hemaglutinação/efeitos dos fármacos
-Bactérias/crescimento & desenvolvimento
Eletroforese em Gel de Poliacrilamida
Inibidores do Crescimento
Testes de Sensibilidade Microbiana
Limites: Animais
Coelhos
Camundongos
Responsável: BR1.1 - BIREME


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Todorov, Joäo Claúdio
Id: lil-123714
Autor: Todorov, Joäo Claudio.
Título: Progressos no estudo das bases neurais da aprendizagem / Advances in the study of the neural basis of learning
Fonte: Psicol. teor. pesqui;7(3):303-10, set.-dez. 1991.
Idioma: pt.
Resumo: O estudo dos mecanismos neurais da aprendizagem revelou considerável progresso nos últimos vinte anos. A possibilidade de experimentaçäo com invertebrados tem levado a descobertas importantes sobre as mudanças funcionais e estruturais, a nível celular, que acompanham processos simples de aprendizagem como a habituaçäo e a sensitizaçäo
Descritores: Habituação Psicofisiológica
Aprendizagem
Neurônios
-Aplysia
Responsável: BR85.1 - Biblioteca Dante Moreira Leite



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