Objective: To determine the differential synapse plasticity-associated gene expression in PHT-resistant and PHT-responder epilepsy rat brain. Methods: Phenytoin-resistant and phenytoin-responder epilepsy rat model was build and the genes expression associated with synapse plasticity by cDNA microarray were studied. The four thousand and ninety-six target genes were arrayed onto glass slide. Both the mRNA from phenytoin-resistant and phenytoin-responder brains of kindling rats were reversal transcribed to cDNAs as hybridization probes which were labeled with either Cy3-dUTP or Cy5-dUTP at the same time. After hybridization with BioDoor4096 cDNA microarray

the results were analyzed by ImaGene3.0 software. Results: In the PHT- resistant and non-resistant epileptic rats

eighteen differential expressed genes which are associated with snapse plasticity were identified. Conclusion: The enhancement of synapse plasticity may be one of the important causes of drug-resistant epilepsy.