effect of synchronized running activity with chronic stress on passive avoidance learning and body weight in rats

Different stressors induce learning and memory impairment and physical activity influence learning and memory enhancement. In this research, we investigated the effect of synchronized running activity with stress on acquisition and retention time of passive avoidance test. Male Wistar rats were randomly divided into five groups as follows: Control [Co], Sham [Sh], Exercise [Ex], Stress [St], synchronized exercise with stress [St and Ex] groups. Chronic restraint stress was applied by 6 h/day for 21 days and treadmill running 1 h/day for 21 days. For evaluation of learning and memory, initial and step-through latency were determined at the end of study by using passive avoidance learning test. Our results showed that: [1] Exercise under no stress provides beneficial effects on memory acquisition and retention time compared to Control group; especially retention time had significantly [P < 0.05] increased in exercised group. [2] Chronic stress with and without synchronized exercise significantly [P < 0.01, P < 0.05, respectively] impaired acquisition and retention time. [3] Body weight differences were significantly [P < 0.01, P < 0.001 and P < 0.001] lower than Control group in exercise, stress and synchronized exercise with stress groups, respectively. [4] Adverse effects of restraint stress [psychical stress] were probably greater than physical activity effects on learning, memory and weight loss. The data confirmed that synchronized exercise with stress had not significantly protective role in improvement of passive avoidance acquisition and retention time; hence it did not significantly improve learning and memory deficit in stressed rats; whereas exercise alone could improve memory deficit in rats

effect of synchronized forced running with chronic stress on short, mid and long- term memory in rats

Impairment of learning and memory processes has been demonstrated by many studies using different stressors. Other reports suggested that exercise has a powerful behavioral intervention to improve cognitive function and brain health. In this research, we investigated protective effects of treadmill running on chronic stress-induced memory deficit in rats. Fifty male Wistar rats were randomly divided into five groups [n=10] as follows: Control [Co], Sham [Sh], Stress [St], Exercise [Ex] and Stress and Exercise [St and Ex] groups. Chronic restraint stress was applied by 6h/day/21days and also treadmill running at a speed 20-21m/min for 1h/day/21days. Memory function was evaluated by the passive avoidance test in different intervals [1, 7 and 21 days] after foot shock. Our results showed that: 1] Although exercise alone showed beneficial effects especially on short and mid-term memory [P<0.05] in comparison with control group, but synchronized exercise with stress had not significantly improved short, mid and long-term memory deficit in stressed rats. 2] Short and mid-term memory deficit was significantly [P<0.05] observed in synchronized exercise with stress and stress groups with respect to normal rats. 3] Memory deficit in synchronized exercise with stress group was nearly similar to stressed rats. 4] Helpful effects of exercise were less than harmful effects of stress when they were associated together. The data correspond to the possibility that although treadmill running alone has helpful effects on learning and memory consolidation, but when it is synchronized with stress there is no significant benefit and protective effects in improvement of memory deficit induced by chronic stress. However, it is has a better effect than no training on memory deficit in stressed rats