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1.
Acta Universitatis Medicinalis Anhui ; (6): 1426-1430, 2015.
Artigo em Chinês | WPRIM | ID: wpr-478582

RESUMO

Objective To investigate the way of fear conditioning memory model evoked and erased by foot-shock in tree shrew. Methods First, detect the tree shrew activities regularly in light/dark box. Second, test a suitable voltage degree of foot shock on tree shrew. Third, investigate the memory formation and erasing of fear conditioning on tree shrew of trial group. Results The duration of tree shrew (n=4) stay in the dark-box was significantly lon-ger than that of in the light box (P<0. 01) in normal condition. In the same environment of two light boxes, given different voltage degrees, the durations of tree shrew (n=6) stay in the stimulating chamber gradually reduced and the durations of tree shrew stay had significant difference between stimulatus chamber and no stimulatus chamber when the stimulus voltage up to 12 V ( P<0. 05 ) , 16 V ( P<0. 01 ) and 20 V ( P<0. 01 ) . The animal of trial group ( n=4 ) could build up the fear conditioning memory of the dark box with the stimulus of 16 V foot-shock in the dark box ( P<0. 001 ) . After formation of the fear conditioning memory, the same stimulus in light box ap-peared for 4 days. The durations of tree shrew stay in trial group (n=4) decreased in light box, and there was no significant difference between the trial group and the control group. Conclusion Tree shrew prefers to stay in the dark box. The suitable voltage for foot-shock on tree shrew is 16 V. The fear conditioning memory can be evoked and erased by foot-shock.

2.
Mem. Inst. Oswaldo Cruz ; 86(supl.2): 169-171, 1991. tab
Artigo em Inglês | LILACS | ID: lil-623963

RESUMO

In rats pre-but not post-training ip administration of either flumazenil, a central benzodiazepine (BSD) receptor antagonist, or of n-butyl-B-carboline-carboxylate (BCCB), an inverse agonist, enhanced retention of inhibitory avoidance learning. Flumazenil vlocked the enhancing effect of BCCB, and the inhibitory effect of the BZD agonists clonazepam and diazepam also given pre-training. Post-training administration of these drugs had no effects. The peripheral BZD receptor agonist/chloride channel blocker Ro5-4864 had no effect on the inhibitory avoidance task when given ip prior to training, buth it caused enhancement when given immediately post-training either ip or icv. This effect was blocked by PK11195, a competitive antagonist of Ro5-4864. These results suggest that ther is an endogenous mechanism mediated by BZD agonists, which is sensitive to inverse agonists and that normally down-regulates the formation of memories through a mechanism involving GABA-A receptors and the corresponding chloride channels. The most likely agonists for the endogenous mechanism suggested are the diazepam-like BZDs found in brain whose origin is possibly alimentary. Levels of these BZDs in the cortex were found to sharply decrease after inhibitory acoidance training or mere exposure to the training apparatus.


Assuntos
Animais , Ratos , Benzodiazepinas/metabolismo , Benzodiazepinas/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/fisiologia , Diazepam/farmacologia , Proteínas de Membrana/efeitos dos fármacos , Aprendizagem da Esquiva/efeitos dos fármacos , Ratos Wistar , Canais de Cloreto
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