Abstract: Objective To investigate the effect of Shenlongtang decoction (SLT) on the learning and memory ability and serum level of
neuropeptide Y (NPY) and expression of NPY in hippocampus of rats with cerebral ischemia/reperfusion. Methods 50 rats were randomly divided into 5 groups: control group with sham operation; model group with cerebral ischemia/reperfusion; pisacetam group as positive control;and SLT groups (low and high dosages). The rats' model was established with two-vessel occlusion. After modeling, the rats were administrating with SLT or pisacetam for 28 d. Learning and memory ability was tested with Morris water maze, the level of NPY was detected with radioimmunoassay, and the number of positive cells of NPY in hippocampus was detected. Results Compared with the control group, the latency time increased significantly and frequence of searching submerged platform decreased significantly in the model group (P<0.01); and compared with the model group, the latency time decreased significantly and frequence of searching submerged platform increased significantly in SLT high dosage group (P<0.05). Compared with the control group, the serum levels of NPY increased significantly in the model group, and the number of positive cell of NPY in hippocampus area significantly increased (P<0.01); and compared with the model group, the serum levels of NPY decreased significantly, and the number of positive cell of NPY in hippocampus area significantly decreased in the SLT high dosage group and pisacetam group (P<0.05). Conclusion SLT could improve the learning and memory function.The mechanism may be related to regulate the serum level and expression of NPY in hippocampus area of rats with cerebral ischemia/reperfusion.

Key words: Shenlongtang decoction, ischemia/reperfusion, learning, memory, neuropeptide Y