Objective: To study the role of NMDA receptor in learning and memory deficit caused by microwave irradiation.
Methods: At the time of Oh, 3h, 12h, 24h, 3d after microwave irradiation of 65mW/cm2 exposure for 20min (SAR 12.0 W/kg), rats were decapitated under deep anesthesia, the hippocampus was quickly removed, then expressions of NR1, NR(2A), NR(2B), NR(2C), NR(2D) subunits of NMDA receptor were measured by RT-PCR.
Results: Compared with control, the mRNA expressions of NR1 decreased in 21.1% (P < 0.05),and in 14.2% (P < 0.05), and in 30.3% (P < 0.01) respectively at timepoints of 3h, 24h, 3d after microwave exposure. At timepoints of Oh, 3h, 12h after microwave exposure, the mRNA expressions of NR(2A) decreased in 37.0% (P < 0.01), and in 35.9% (P < 0.05), and in 35.3% (P < 0.05) respectively. The mRNA expressions of NR(2B) did not statistically change after microwave exposure. The mRNA expressions of NR(2C) decreased in 24.3% (P < 0.05), and in 27.1% (P < 0.05) respectively at timepoints of Oh, 24h after microwave exposure. At timepoints of Oh, 12h, 24 h, 3 d after microwave exposure, the mRNA expressions of NR(2D) increased in 67.9% (P < 0.05), and in 45.7% (P < 0.05), and in 49.7% (P < 0.01), and in 75.4% (P < 0.01) respectively.
Conclusion: The results indicated that the composition of subunits comprising NMDA receptor could be altered and autoregulation of NMDA receptor in the rat hippocampus exposed by microwave could decrease. These changes could be correlated with impaired LTP induced by microwave irradiation.