Riluzole inhibits the release of glutamate in the caudate nucleus of the cat in vivo.

When applied locally to the caudate nucleus of the halothane-anaesthetized cat, riluzole (10(-5) M) markedly reduced (-57%) the spontaneous release of glutamate. This effect seems to be specific, since the efflux of the other amino acids, including aspartate was not affected. Indicating further its selective inhibitory effect on the spontaneous release of glutamate, the prolonged (90 min) application of riluzole (10(-5) M) enhanced the size of the potassium-releasable pool of glutamate, but not that of aspartate. This effect of riluzole was not noticed with classical anti-glutamatergic drugs, tested in the same conditions.