In order to link major brain receptor complex levels to in vivo electrically induced LTP, a bipolar stimulation electrode was chronically implanted into the perforant path, while two monopolar recording electrodes were implanted into the dentate gyrus of the dorsal hippocampus. The recording electrode was measuring extracellular excitatory postsynaptic potentials, while the other one measured population spikes. Immunoblotting of native receptor proteins was carried out in the DH based upon blue-native gel electrophoresis and immunoprecipitation followed by mass spectrometrical identification of the NR1-GluA1-GluA2 complex was used to provide evidence for complex formation. The induction of LTP in DH was proven and NMDA receptor complex levels containing NR1, GluA1, GluA2 and GluA3 were modulated by LTP induction. The LTP-associated changes of receptor complex levels may indicate concerted action, interaction and represent a pattern of major brain receptor complexes in the DH following electrical induction of LTP in the rat.