Anticonvulsant action of stereoisomers of gamma-glutamylaminomethylsulphonic acid in mice.

The effects of stereoisomers of gamma-glutamylaminomethylsulphonic acid (GAMS) on convulsions produced by intracerebroventricular injections of excitatory amino acids were studied in mice. gamma-D-GAMS preferentially blocked myoclonic seizures induced by kainate and had less pronounced anticonvulsant effect against quisqualate, N-methyl-D-aspartate, quinolinate, D-homocysteine sulphinate and L-glutamate. gamma-L-GAMS displayed only a relatively weak protective effect against kainate- and, to some extent, quisqualate-induced seizures, with little or no effect on the convulsant properties of the other excitatory amino acids. These results indicate that the D configuration of the gamma-carbon atom of excitatory amino acid antagonists is preferred not only for NMDA receptor antagonism but for antagonism at non-NMDA receptors as well.