Effects of repeated (40 s¡Á5) +Gz exposures on learning and memory of rats during postª²ischemic recovery

    CAO Xinª²Sheng, WU Yanª²Hong, SUN Xiª²Qing, LIU Tingª²Song, GENG Jie, WU Xingª²Yu

    Department of Aerospace Biodynamics, School of Aerospace Medicine, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To explore the effects of different repeated (40 s¡Á5) +Gz exposures on learning and memory in rats during postª²ischemic recovery. METHODS: Twentyª²four male SD rats were randomly divided into 3 groups: control group(C), +6 Gz/40 s¡Á5 group (+6 Gz), and +10 Gz/40 s¡Á5 group (+10 Gz). Changes of learning and memory performance in rats were measured during 1 week after +Gz exposure. RESULTS: In the open field test, compared to control group, summation of crossing and rearing(SCR) in +6 Gz group declined significantly at 0 d(P<0.01); SCR in +10 Gz group declined significantly at 0 d(P<0.01), and time stay in center grille(TSC) increased significantly at 0 d (P<0.01); compared to +6 Gz group, TSC in +10 Gz group increased significantly at 0 and 4 d(P<0.05). In Yª²maze test, compared to control group, there were no apparent changes of either right reaction number(RR) or time of reaction(TR) in +6 Gz group at all time points; RR in +10 Gz group decreased significantly at 2 d(P<0.01 vs control group), and TR increased significantly at 0 and 2 d(P<0.05, P<0.01 vs control group); compared to +6 Gz group, RR at 0 and 2 d, TR at 0, 2 and 4 d in +10 Gz group changed significantly (P<0.05, P<0.01). In passive avoidance test, there were no apparent changes of all items in +6 Gz or +10 Gz group as compared to control group. CONCLUSION: Repeated (40s¡Á5) +10 Gz exposures may temporarily impair the learning ability in rats. ......