The present study was designed to compare the protective consequences of activation of metabotropic glutamate receptors (mGluRs) on N-methyl-D-aspartate (NMDA)- and kainic acid (KA)-induced excitotoxicity in vivo. Pretreatment with the mGluR agonist 1SR,3RS-1-aminocyclo-pentane-1,3-dicarboxylic acid (tACPD) limited the anatomical and behavioral consequences of the intrastriatal administration of the NMDA agonist quinolinic acid (QA). In contrast, pretreatment with tACPD did not alter the effects of intrastriatal injection of KA.