EFFECT OF BENZO[a]PYRENE ON LEARNING AND MEMORY BEHAVIORS AND THE EXPRESSION OF AMINOACID NEUROTRANSMITTERS IN RATS

[Objective]To probe the effect and possible mechanism of Benzo[a]pyrene(B[a]P)exposure on the capability of learning and memory in rats.[Methods]Forty weaned Wistar rats were randomly divided into 5 groups,including a control group,a solvent control group and three B[a]P-treated groups,which were peritoneal injected different doses of B[a]P every day for 13 weeks.The capability of learning and memory in rats were measured by means of Morris water maze test,and immunohistochemical method was used to observe the expressions of γ-aminobutyric acid(GABA),gliutamic acid(Glu)positive neurons in cerebral cortex and hippocampus.[Results]In training of Morris water maze,the mean escape latency of rats in high,medium dose group were longer than that in the control group,the frequency of crossing platform and the time of swimming in the target area of rats in high,medium dose group were less than that in the control group.The positive average optical densities of Glu,GABA in exposed group were significantly different from that in the control group.[Conclusion]Exposure B[a]P could reduce the capability of learning and memory in rats through reducing the content of Glu,GABA in hippocampus and cerebral cortex.