Abstract: Objective To investigate the effect of chronic administration of benzo (a) pyrene on memory and the expression of glutamate receptor(2-amino-3-hydroxy-5-methyl-4-isoxazol propionate subunit 1,AMPA1) mRNA in hippocampus of rats.Methods Thirty-six healthy male rats were randomly divided into high,moderate and low dose toxin exposure groups and vehicle group(9 in each group).Afterw ards,the rats were tested for learning and memory (Morris water maze),and the high exposure and vehicle group were studied with gene microarray screening and real-time PCR for AMPA1 mRNA in hippocampus.Results Compared with the control group (6.50±2.57s),latency in finding the platform of the rats in high exposure group (17.90±7.71s) and moderate exposure group (16.20±4.74s) increased significantly (P<0.05) on the fifth day of place navigation.The cDNA microarray analysis showed that AMPA1 mRNA level in high exposure group was 2.052 times higher than that of the vehicle group.Real-time PCR showed that AMPA1 mRNA was up-regulated by 4.257 times.Conclusion Benzo(a) pyrene had an inhibitive effect on spatial learning and memory capability,and significantly increase gene expression of AMPA1 subunit in hippocampus of rats.