Effects of gamma knife irradiation on the expression of NMDA receptor subunits in rat forebrain

Objective: To examine the effects of gamma knife surgery (GKS) on the expression of N-methel-d-asparate receptor (NMDAR) subunits in rat forebrain. Materials and methods: Using stereotactic technique, we performed gamma knife irradiation on the left forebrain of 13 male Wistar rats with a maximum dose of 60 Gy. These animals were raised for 24 h, 30 and 60 days before they were killed. Then immunohistochemistry was applied to detect the relative levels of NMDAR subunits (NR1, NR2A, and NR2B) in the target region. Results: The expression of NR1 and NR2A but not NR2B increased significantly in the cortex 30 and 60 days after irradiation. However, no significant differences in the expression of these three subunits were detected in the caudate putamen at all time points. Conclusion: gamma knife irradiation induced the upregulation of NMDAR subunits, NR1, and NR2A, which might represent a possible mechanism underlying the therapeutic effects of gamma knife irradiation on many neurological diseases, including drug resistance epilepsy.