DOPAMINERGIC CONTROL OF KYNURENATE LEVELS AND N-METHYL-D-ASPARTATE TOXICITY IN THE DEVELOPING RAT STRIATUM

This study was designed to examine the effects of d-amphetamine (D-AMP H) and D1- and D2-selective dopaminergic drugs on the concentration of the broad-spectrum excitatory amino acid receptor antagonist kynureni c acid (KYNA) in the striatum of developing and adult rats. At all age s, KYNA levers were significantly reduced 1 h after the systemic admin istration of D-AMPH (5 mg/kg). SKF 38393 (5 mg/kg) and quinpirole (2 m g/kg) also caused a rapid decrease in striatal KYNA, but only in postn atal day (PND) 7 and 14 rats. All these effects were readily prevented by specific dopamine receptor antagonists. The possible functional si gnificance of the reduction in KYNA. levels was tested in PND 14 anima ls. When pretreated with D-AMPH (5 mg/kg), these rats showed markedly increased vulnerability to an intrastriatal injection of the excitotox in NMDA. These data suggest that KYNA plays a role as a mediator of do pamine-glutamate interactions in the rat striatum.