Attenuation of neostriatal preproenkephalin and preprotachykinin mRNA abundance by chronic treatment with the kainate/quisqualate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione in the rat brain.

The present investigation assessed the effect of chronic blockade of kainate/quisqualate binding sites with 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on preproenkephalin (PPE) and preprotachykinin (PPT) mRNA abundance in the neostriatum of the rat brain. Daily injection of CNQX for seven consecutive days decreased PPE mRNA abundance approximately 25% below vehicle-injected controls in dorsolateral, dorsomedial, anterior caudate-putamen (dlCPu, dmCPu and aCPu, respectively) and nucleus accumbens (NAc). Similarly, PPT mRNA abundance was significantly decreased in dlCPu, dmCPu and aCPu but not in the accumbens. The data demonstrate that non-NMDA receptor activity modulates basal levels of expression of PPE and PPT mRNAs in the neostriatum of the rat brain.