عنوان مقاله [English]
Stress is one of the most important internal destabilizing factors and has significant negative effects on cognitive functions. Stress induction using the chronic unpredictable stress (CUS) model has been extensively studied in several animal models to investigate the effect of stress exposure, including exposure to stressors randomly, intermittently and unpredictably. CUS has probably been shown to induce memory dysfunction of the chronic stress response. The aim of this study was to investigate the incidence of learning and spatial memory impairment in the Morris water maze (MWM) test after induction of CUS for 6 consecutive days. Adult male rats were randomly divided into control groups (without CUS) and stress (induction of CUS for 6 consecutive days). Animal stress, learning, and spatial memory were assessed by the elevated plus maze (EPM) and the MWM, respectively. CUS reduced performance in spatial learning and memory. The time and distance spent to reach the hidden platform in the stress group compared to the control group in a total of four training days showed an increasing trend. So that in the fourth days, a significant increase (p < 0.05) was observed in both parameters. Also, induction of stress led to a significant reduction in the percentage of time in the target quadrant compared with the control group (p < 0.01). In the EPM, the stress group showed a significant decrease in the percentage of time spent in the open arm compared to the control group (p < 0.05). The present study, by exposing male mice to unpredictable stress for 6 days, stated that, due to the ineffectiveness of the stress induction strategies used, achieving a hidden platform location in the MWM over time and distance more has been done.