Comparison of Handling-Injection Stress with Noise Stress on Learning and Memory in the Early Life of Male Rats

Various stressful stimuli have different effects on memory and learning. With technology development, the human exposes to different stressful factors. The aim of this study was to investigate the combined effects of handling-injection stress with noise stress in the passive avoidance task in rats. Twenty-four male Wistar rats (22 days aged) with weight of 55gr were used. Male Wistar rats were divided into 4 groups, of 6 animals for 4 weeks: subcutaneous injection of sodium chloride 0.9% and handling stress (I+H), subcutaneous injection of sodium chloride 0.9% and handling with noise exposure (I+N), noise exposure (N) and control (C). After 4 weeks, we studied passive avoidance conditioning test in a shuttle box. The step-through latency after training animals significantly increased in (I+H) group as compared with (I+N) and (N) groups (p=0.001). But using noise stress with handling-injection stress significantly attenuated learning and memory in the (I+N) group than other 3 groups (p=0.01). The data suggested that using moderate stress with sound stress decreases learning and memory in the early life of male Wistar rats.