Concomitant increases in the extracellular concentrations of excitatory and inhibitory amino acids in the rat hippocampus during forebrain ischemia.

The extracellular concentrations of aspartate, glutamate, glutamine, taurine and gamma-aminobutyric acid in the hippocampus were determined during and after forebrain ischemia (4-vessel model) in the unanaesthetized rat. Ischemia led to a large increase in both inhibitory (taurine and gamma-aminobutyric acid) and excitatory amino acids (aspartate, glutamate). These results suggest that in this model, as previously proposed in other models of ischemia, the large increase of inhibitory amino acids could counterbalance the excitotoxicity due to aspartate and glutamate.