Abstract: Objective To study effects of heroin and ephedrine on the structure of cerebral temporal lobe cortex and capability of learning and memory in filial mice. Methods One hundred and eight filial mice were given intraperitoneal injection of heroin and ephedrine by gradually increase of doses, the filial mice behavior changes were observed by bait maze. In the same time, the changes of the cell structure of cerebral temporal lobe cortex were observed by light microscope and transmission electron microscopy. Expression of Bax protein and keratinocyte growth factor(KGF) were measured by immunohistochemical method, the ChAT activity was detected by colorimetry. Results Error frequency and total test time of bait maze in the heroin group and ephedrine group were significantly higher than those in the control group(EM>P/EM><0.05 or EM>P/EM><0.01) except those at 5 days in the ephedrine group (EM>P/EM>>0.05), and the above-mentioned two indexes of the heroin group were significantly higher than those of the ephedrine group(EM>P/EM><0.05 or EM>P/EM><0.01). After administration of heroin and ephedrine at 5,10,15,20 days, the dendrites and axon of pyramidal neurons in cerebral temporal lobe cortex were atrophied and the cell bodies became smaller. Nuclear membrane lost normal round contour and the structures of organelles showed abnormal or vacuolar. The matrix around capillary dissolved or were destructed and capillary lumen became narrow. The synaptic vesicles were reduced. The number of apoptotic or necrotic cells and Bax protein and KGF-immunopositive neurons was significantly higher and ChAT activity was lower than that of the control group after administration of heroin and ephedrine(EM>P/EM><0.05 or EM>P/EM><0.01). There were differences between the heroin group and ephedrine group in the number of apoptotic or necrotic cells and expression of Bax protein and KGF(EM>P/EM><0.05 or EM>P/EM><0.01). Error frequency of bait maze, the number of apoptotic or necrotic cells and Bax proteinand KGF-immunopositive neurons were increased by the increase in doses of heroin and ephedrine. Conclusion Heroin and ephedrine had great effect on learning and memory in filial mice and this effects could be related with the damage of the histological structure of cerebral temporal lobe cortex and low activity of ChAT.

Key words: Heroin, Ephedrine, Cerebral temporal lobe cortex, Learning and memory, ChAT, Immunohistochemistry, Filial mouse