The present study aims to identify and characterize genes that cause differen genes between non-responders and responders to electroacupuncture (EA) on mechanical allodynia following peripheral nerve injury. Under sodium pentobarbital anesthesia, animals were subjected to unilateral transection of the superior caudal trunk at the level between S1 and S2 spinal nerves. EA stimulation (2Hz, 0.3 ms, 0.2-0.3 mA) was delivered to Zusanli (ST36) for 30 min 2 weeks after the surgery. The degree of mechanical allodynia was assessed quantitatively by touching the tail with von Frey hair (2.0 g) at 10 min intervals. The rats, which showed an EA-induced decrease of response frequencies under 10 %, were classified as non-responders and those displaying an EA-induced decrease of response frequencies 20 % or more were classified as responders. Results from oligonucleotide microarray, to which cDNAs from the spinal dorsal horn (DH) were applied, showed that hemoglobin beta chain complex and chondroitin sulfate proteoglycan-5 decreased and limbic system-associated membrane protein increased in the non-responder group, whereas calcium-independent alpha-Iatrotoxin receptor homolog-3 increased in the responder group. These results suggest that The functional abnormality of molecules regulating cell adhesion, intracellular signal transduction and cell differentiation in the spinal DH may be involved in the anti-allodynic effect of EA.