Abstract: To observe the effect of the herbal medicine CUZHIFANG on synaptophysin immunoreactivity in hippocampus of aged learning and momory impaired rats. Methods: Sixty male healthy rats (10 young and 50 old)were examined with Morris water maze. The old rats were divided into senile memory deficits rats (SMD) and senile memory normal rats (SMN).The SMD were further divided into CUZHIFANG group and SMD control group (SMDc). The synaptophysin (SYN) immunolabeling density was estimated in freezed sections of hippocampal formation of rats by the aid of image analysis system. Results: A significant increase (P＜0.01) in the value of the calibrated optic density (COD) of synaptophysin immunoreactivity particles was found in the hippocampus CA3 in the CUZHIFANG group, compared with the SMDc group. Conclusion： CUZHIFANG improves learning and memory of aged rats in morphology. The probable mechanism of CUZHIFANG is by increasing hippocampal synaptic density in CA3.

Key words: CUZHIFANG, Learning and memory deficit, Hippocampus, Synaptophysin