Effects of +6 Gz and noise combined stress on learning and memory in rats

    SUN Xiª²Qing, LIU Tingª²Song, CAO Xinª²Sheng£¬ WU Xingª²Yu

    Department of Aerospace Biodynamics, School of Aerospace Medicine, Fourth Military Medical University, Xi¡¯an 710033£¬ China

    ¡¾Abstract¡¿ AIM: To study the effects of combined stress of noise and moderate +Gz on learning and memory in rats. METHODS: Thirtyª²two male SD rats were randomly divided into four groups with 8 rats in each group: control group, +6 Gz/3 min group, 90 dB(A)/30 min noise group, +6 Gz/3 min and 90 dB(A)/30 min noise combined stress group and the changes of learning and memory after stress were measured by Yª²maze test and stepª²through test. RESULTS: As compared with that in control group, the percentage of right reaction decreased significantly (P©‚0.01) and the reaction time increased significantly (P©‚0.01) in +Gz group at 2 d, 4 d and 6 d after +Gz exposure. When compared with that in control and noise group, the percentage of right reaction decreased significantly (P©‚0.01) and the reaction time increased significantly (P©‚0.01) at all time points in combined stress group, but no significant changes were observed when compared with that in +Gz group. As compared with that in control group, the total time and number of error increased significantly (P©‚0.01) while latent time decreased significantly immediately and 6 days after stress (P©‚0.05) in combined stress group. CONCLUSION: It is suggested that combined stress of +6 Gz/30 min and 90 dB(A)/30 min noise may cause sustained impairment of learning and memory in rats. ......