γ-D-Glutamylglycine (γ-DGG) is an antagonist of the excitatory amino acids NMDA , quisqualate, kainate, and glutamate.¹It decreases the amplitude of excitatory post-synaptic potentials (EPSPs) in electrically stimulated rat hippocampal slices when used at a concentration of 200 mM. Subdural administration of γ-DGG inhibits NMDA-, kainate-, or quisqualate-induced paw biting, indicating antinociceptive activity, in mice (EC₅₀s = 63, 9.5, and 31 µM, respectively).²γ-DGG reduces sound-induced wild running and inhibits the clonic and tonic phases of sound-induced seizures in DBA/2 mice (ED₅₀s = 0.058, 0.046, and 0.054 µmol, i.c.v., respectively).³

1.Crunelli, S., Forda, S., and Kelly, J.S.Blockade of amino acid-induced depolarizations and inhibition of excitatory post-synaptic potentials in rat dentate gyrusJ. Physiol.341627-640(1983) 2.Raigorodsky, G., and Urca, G.Spinal antinociceptive effects of excitatory amino acid antagonists: Quisqualate modulates the action of N-methyl-D-aspartateEur. J. Pharmacol.182(1)37-47(1990) 3.Croucher, M.J., Collins, J.F., and Meldrum, B.S.Anticonvulsant action of excitatory amino acid antagonistsScience216(4548)899-901(1982)