Effects of AMPA/kainate receptor blockade on responses to dopamine receptor agonists in the core and shell of the rat nucleus accumbens

The present experiments were conducted to investigate effects of alpha-amin o-3-hydroxy-5-methyl-4-isoxazoleprionic acid (AMPA)/kainate receptor blocka de (CNQX, NBQX) on locomotor responses to D2/3 (7-OH-DPAT) and D1 [(+)-SKF 38393] dopamine receptor agonists in the nucleus accumbens (NAS) core and s hell. CNQX (0.25-0.5 mu g) microinjected into the NAS core or shell did not affect baseline locomotor activity. 7-OH-DPAT (2.5-5 mu g) decreased locom otor activity. Coadministration of CNQX (0.5 mu g) increased the effects of 7-OH-DPAT (5 mu g) in the NAS core and shell. A similar increase was obser ved with NBQX (0.5 Gig) in the NAS shell. (+)-SKF 38393 (5 mu g) into the N AS core and shell increased locomotor activity after 30 min; this effect wa s not altered by CNQX (0.5 mu g). As the D2/3 dopamine agonist (-)-quinpiro le (2 mu g) increased effects of (+)-SKF 38393 (5 mu g) in NAS shell but no t core, lack of site-selective effects of (+)-SKF-38393 and of 7-OH-DPAT wi thin NAS is not attributable to drug diffusion. The previous observation th at glutamate effects on locomotor activity depend on the relative involveme nt of D1 or D2/3 dopamine receptors in the NAS was based on the dopamine-de pletion model. The present results demonstrate differential interactions of AMPA receptor blockade with dopamine agonists in "dopamine-intact" animals .