NMDA glutamate receptor stimulation is required for the expression of D2 dopamine mediated responses in apomorphine primed 6-hydroxydopamine lesioned rats.

Three priming injections with the D1/D2 dopamine agonist apomorphine permits a challenge with the D2 agonist quinpirole to elicit robust contralateral rotation and ipsilateral striatal Fos expression in 6-hydroxydopamine lesioned rats. Pretreatment with NMDA glutamate antagonists MK-801 or CPP dose-dependently attenuates these quinpirole-mediated responses. These findings suggest that concomitant NMDA receptor stimulation is required for the expression of D2-mediated responses in apomorphine primed dopamine-depleted rats.