Objective To explore the effects of different doses of topiramate (TPM) on the expression of nerve cell adhesion molecule (NCAM) and growth-associated protein 43 (GAP- 43) mRNA in hippocampus of rats with epilepsy. MethodsForty-eight rats were randomly divided into normal control group, kainic acid (KA) group, 10 mg/kg TPM group, 40 mg/kg TPM group, 100 mg/kg TPM group and 400 mg/kg TPM group (n=8). The models of rats with epilepsy treated by different doses of TPM were established. The behavior of rats was observed, and the expression of NCAM and GAP- 43 mRNA in hippocampus of rats was determined by Real-time PCR. Results The expression of NCAM and GAP- 43 mRNA in KA group was significantly higher than that in normal control group (P<0.01), while there was no significant difference between 10 and 40 mg/kg TPM groups and KA group, that in 100 and 400 mg/kg TPM groups was significantly lower than that in KA group (P<0.01), and that in 400 mg/kg TPM group was significantly lower than that in 100 mg/kg TPM group (P<0.01). Conclusion KA can up-regulate the expression of NCAM and GAP- 43 mRNA in hippocampus of rats with epilepsy. Higher dose of TPM can inhibit the expression of NCAM and GAP- 43 mRNA, and the inhibitory effect is related with the dose of TPM.