Post-session intra-perifornical region quinpirole infusions retard the consolidation of an appetitive differential conditioning task

We have shown previously that post-session infusions of the D2/D3 dopamine receptor antagonist sulpiride within the perifornical region of the lateral hypothalamus (PFH) greatly facilitated the acquisition of an appetitive di fferential conditioning task. Here, we have examined the effects of the D2/ D3 dopamine receptor agonist quinpirole on acquisition of this task. Condit ioning sessions consisted of an initially neutral stimulus (CS+) preceding availability of a 10% sucrose reward (US), and a control stimulus (CS-), ne ver associated with the US, were presented, followed by bilateral intra-PFH infusions of quinpirole (0, 0.1, 10 nmol). The acquisition of a conditione d approach response during the CS+ period was impaired by quinpirole admini stration in a dose-dependent manner. No other behavioural measure,vas affec ted. All groups subsequently acquired the conditioned approach response, fo llowing cessation of the post-session infusion procedure. The present data extends previous findings, suggesting that the level of activation of dopam ine receptors in the vicinity of the PFH significantly influences the conso lidation of appetitive Pavlovian associations. (C) 1999 Lippincott Williams & Wilkins.