ANTICONVULSANT EFFECT OF (1S-3R)-1-AMINOCYCLOPENTANE-1,3-DICARBOXYLIC ACID (ACPD) - A SELECTIVE METABOTROPIC GLUTAMATE-RECEPTOR AGONIST, ON AMYGDALOID-KINDLED RATS

The present study examined the effect of microinjection of a selective metabotropic glutamate receptors (mGluRs) agonist, (1S,3R)-1-aminocycropentane-1,3-dicarboxylic acid (ACPD), into the amygdala in rats. In non-kindled rats, intra-amygdaloid injection of 200 nmol of ACPD produced spiking activity associated with limbic behavioral seizures, including immobility, searching, and wet-dog shakes. The same dose of ACPD injected into the amygdala caused no EEG or behavioral changes in kindled rats. Subsequently, the effect of intra-amygdaloid injection of ACPD on kindled seizures was examined. The 40 nmol dose markedly suppressed kindled seizures 3 days after the injection. A similar and significant anticonvulsant effect was observed 24 hours after 200 nmol of ACPD. These results suggest that kindling manipulation reduces excitability of the amygdala induced by ACPD, and that mGluRs in the kindled amygdala exert an inhibitory action against kindled seizures.