Análise dos efeitos da morina sobre a memória de reconhecimento e esquiva inibitória em ratos

摘要

Various studies have demonstrated the beneficial potential of flavonoids on many biological aspects, which lead to the prescription of many of those substances as food supplements to prevent or to correct functional alterations, especially the ones concerning aging. Morin presents the potential to protect the cardiovascular system against oxidative stress and also presents very promising anti-tumor effects on the treatment of neoplasias. However, other studies demonstrate that morin is pro-oxidant because it induces the production of superoxide (O2 -) and hydrogen peroxide (H2O2) and because it causes damage to DNA in lymphocyte cultures and it inhibits the enzymeglutathione reductase. Once many studies indicate that free radicals, besides being involved in pathogeny of many illnesses, are involved in changes and illnesses associated to aging, including the decline of cognitive performance, particularly learning and memory, the present study aims at analyzing the acute effect of different doses of morin on recognition memory and inhibitory avoidance in mice submitted to behavioral tasks. The animals submitted to the task of recognizing a new object were administrated intraperioneal injections of vehicle or morin (Sigma) (5mmol/Kg e 50mmol/Kg ) 96 hours before the training session or immediately after task training. Mice that received morin before training, in both doses, presented complete block of STM and LTM. In mice that received the 5,0mmol/Kg dose immediately after training, amnesiac effect of STM and LTM was observed, while mice that received the 50,0mmol/Kg dose presented only LTM block. The total time of exploration of objects during task training session in which the animals received morin before training was statistically different between the groups that received vehicle solution and the groups that received morin. Such fact lead us to consider that morin may have some other unspecific effect on the exploratory locomotion activity, motivation or anxiety. Exposed to inhibitory avoidance task, animals were administrated intraperitoneal injections of morin in 50,0mmol/Kg doses 96 hours before the training session and 5,0mmol/Kg and 50,0mmol/Kg doses in two different moments: 30 before training and immediately after training. In none of the doses or moments memory deficits were found. As a whole, the results found in this study indicate that the effects of morin on memory depend on the content of the behavioral task, once it damaged a neutral task and it did not provoke alterations in an aversive task. However, we suggest the accomplishment of additional studies which evaluate the effect of this flavonoid on other neurobehavioral aspects, which could influence the performance of animals in memory tasks.