A SINGLE SOCIAL STRESS-EXPERIENCE ALTERS GLUTAMATE RECEPTOR-BINDING IN RAT HIPPOCAMPAL CA3 AREA

The distribution of glutamate receptors in the rat hippocampus was inv estigated 24 h after the social stress of confrontation with a dominan t opponent. AMPA-type glutamate receptors were labeled with the antago nist [H-3]CNQX, and NMDA-type receptors were labeled with the competit ive antagonist [H-3]CGP39653. Increased [H-3]CGP39653 labeling was exc lusively found in the CA3 stratum radiatum and a decreased [H-3]CNQX l abeling was found in several hippocampal areas. Consequently, the rati o NMDA/AMPA binding was significantly increased in CA3 stratum oriens and CA3 stratum radiatum, These results suggest that a single unescapa ble social stress of defeat alters the impact of the excitatory neurot ransmitter glutamate, which is restricted to hippocampal CA3 neurons. Possible consequences of the present findings are discussed.