Excitatory amino acid antagonists depress transmission in hippocampal projections to the lateral septum.

Antagonists of excitatory amino acid neurotransmission were tested as antagonists of septal excitatory postsynaptic potentials (EPSPs) generated by stimulation of the fimbria. Septal EPSPs were depressed in a concentration-dependent manner by kynurenic acid and P-bromobenzoyl piperazine-2,3-dicarboxylic acid but not by L-2-amino-4-phosphonobutyric acid or D-2-amino-5-phosphonopentanoic acid. These results indicate that the hippocampal projection to the lateral septum is similar to the Schaffer collateral system and is mediated by an excitatory amino acid or a similar derivative.